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pigweed / third_party / github / project-chip / connectedhomeip / 4b3da132ce2e83efc0292d165bef1d8b36bd16f6 / . / src / crypto / CHIPCryptoPAL.h
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/*
*
* Copyright (c) 2020-2023 Project CHIP Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @file
* Header that exposes the platform agnostic CHIP crypto primitives
*/
#pragma once
#if CHIP_HAVE_CONFIG_H
#include <crypto/CryptoBuildConfig.h>
#endif // CHIP_HAVE_CONFIG_H
#include <system/SystemConfig.h>
#include <lib/core/CHIPError.h>
#include <lib/core/CHIPVendorIdentifiers.hpp>
#include <lib/core/Optional.h>
#include <lib/support/BufferReader.h>
#include <lib/support/CodeUtils.h>
#include <lib/support/SafePointerCast.h>
#include <lib/support/Span.h>
#include <stddef.h>
#include <string.h>
namespace chip {
namespace Crypto {
inline constexpr size_t kMax_x509_Certificate_Length = 600;
inline constexpr size_t kP256_FE_Length = 32;
inline constexpr size_t kP256_ECDSA_Signature_Length_Raw = (2 * kP256_FE_Length);
inline constexpr size_t kP256_Point_Length = (2 * kP256_FE_Length + 1);
inline constexpr size_t kSHA256_Hash_Length = 32;
inline constexpr size_t kSHA1_Hash_Length = 20;
inline constexpr size_t kSubjectKeyIdentifierLength = kSHA1_Hash_Length;
inline constexpr size_t kAuthorityKeyIdentifierLength = kSHA1_Hash_Length;
inline constexpr size_t kMaxCertificateSerialNumberLength = 20;
inline constexpr size_t kMaxCertificateDistinguishedNameLength = 200;
inline constexpr size_t kMaxCRLDistributionPointURLLength = 100;
inline constexpr char kValidCDPURIHttpPrefix[] = "http://";
inline constexpr char kValidCDPURIHttpsPrefix[] = "https://";
inline constexpr size_t CHIP_CRYPTO_GROUP_SIZE_BYTES = kP256_FE_Length;
inline constexpr size_t CHIP_CRYPTO_PUBLIC_KEY_SIZE_BYTES = kP256_Point_Length;
inline constexpr size_t CHIP_CRYPTO_AEAD_MIC_LENGTH_BYTES = 16;
inline constexpr size_t CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES = 16;
inline constexpr size_t kMax_ECDH_Secret_Length = kP256_FE_Length;
inline constexpr size_t kMax_ECDSA_Signature_Length = kP256_ECDSA_Signature_Length_Raw;
inline constexpr size_t kMAX_FE_Length = kP256_FE_Length;
inline constexpr size_t kMAX_Point_Length = kP256_Point_Length;
inline constexpr size_t kMAX_Hash_Length = kSHA256_Hash_Length;
// Minimum required CSR length buffer length is relatively small since it's a single
// P256 key and no metadata/extensions are expected to be honored by the CA.
inline constexpr size_t kMIN_CSR_Buffer_Size = 255;
[[deprecated("This constant is no longer used by common code and should be replaced by kMIN_CSR_Buffer_Size. Checks that a CSR is "
"<= kMAX_CSR_Buffer_size must be updated. This remains to keep valid buffers working from previous public API "
"usage.")]] constexpr size_t kMAX_CSR_Buffer_Size = 255;
inline constexpr size_t CHIP_CRYPTO_HASH_LEN_BYTES = kSHA256_Hash_Length;
inline constexpr size_t kSpake2p_Min_PBKDF_Salt_Length = 16;
inline constexpr size_t kSpake2p_Max_PBKDF_Salt_Length = 32;
inline constexpr uint32_t kSpake2p_Min_PBKDF_Iterations = 1000;
inline constexpr uint32_t kSpake2p_Max_PBKDF_Iterations = 100000;
inline constexpr size_t kP256_PrivateKey_Length = CHIP_CRYPTO_GROUP_SIZE_BYTES;
inline constexpr size_t kP256_PublicKey_Length = CHIP_CRYPTO_PUBLIC_KEY_SIZE_BYTES;
inline constexpr size_t kAES_CCM128_Key_Length = 128u / 8u;
inline constexpr size_t kAES_CCM128_Block_Length = kAES_CCM128_Key_Length;
inline constexpr size_t kAES_CCM128_Nonce_Length = 13;
inline constexpr size_t kAES_CCM128_Tag_Length = 16;
inline constexpr size_t kHMAC_CCM128_Key_Length = 128u / 8u;
inline constexpr size_t CHIP_CRYPTO_AEAD_NONCE_LENGTH_BYTES = kAES_CCM128_Nonce_Length;
/* These sizes are hardcoded here to remove header dependency on underlying crypto library
* in a public interface file. The validity of these sizes is verified by static_assert in
* the implementation files.
*/
inline constexpr size_t kMAX_Spake2p_Context_Size = 1024;
inline constexpr size_t kMAX_P256Keypair_Context_Size = 512;
inline constexpr size_t kEmitDerIntegerWithoutTagOverhead = 1; // 1 sign stuffer
inline constexpr size_t kEmitDerIntegerOverhead = 3; // Tag + Length byte + 1 sign stuffer
inline constexpr size_t kMAX_Hash_SHA256_Context_Size = CHIP_CONFIG_SHA256_CONTEXT_SIZE;
inline constexpr size_t kSpake2p_WS_Length = kP256_FE_Length + 8;
inline constexpr size_t kSpake2p_VerifierSerialized_Length = kP256_FE_Length + kP256_Point_Length;
inline constexpr char kVIDPrefixForCNEncoding[] = "Mvid:";
inline constexpr char kPIDPrefixForCNEncoding[] = "Mpid:";
inline constexpr size_t kVIDandPIDHexLength = sizeof(uint16_t) * 2;
inline constexpr size_t kMax_CommonNameAttr_Length = 64;
/*
* Overhead to encode a raw ECDSA signature in X9.62 format in ASN.1 DER
*
* Ecdsa-Sig-Value ::= SEQUENCE {
* r INTEGER,
* s INTEGER
* }
*
* --> SEQUENCE, universal constructed tag (0x30), length over 2 bytes, up to 255 (to support future larger sizes up to 512 bits)
* -> SEQ_OVERHEAD = 3 bytes
* --> INTEGER, universal primitive tag (0x02), length over 1 byte, one extra byte worst case
* over max for 0x00 when MSB is set.
* -> INT_OVERHEAD = 3 bytes
*
* There is 1 sequence of 2 integers. Overhead is SEQ_OVERHEAD + (2 * INT_OVERHEAD) = 3 + (2 * 3) = 9.
*/
inline constexpr size_t kMax_ECDSA_X9Dot62_Asn1_Overhead = 9;
inline constexpr size_t kMax_ECDSA_Signature_Length_Der = kMax_ECDSA_Signature_Length + kMax_ECDSA_X9Dot62_Asn1_Overhead;
static_assert(kMax_ECDH_Secret_Length >= kP256_FE_Length, "ECDH shared secret is too short for crypto suite");
static_assert(kMax_ECDSA_Signature_Length >= kP256_ECDSA_Signature_Length_Raw,
"ECDSA signature buffer length is too short for crypto suite");
inline constexpr size_t kCompressedFabricIdentifierSize = 8;
/**
* Spake2+ parameters for P256
* Defined in https://www.ietf.org/id/draft-bar-cfrg-spake2plus-01.html#name-ciphersuites
*/
const uint8_t spake2p_M_p256[] = {
0x04, 0x88, 0x6e, 0x2f, 0x97, 0xac, 0xe4, 0x6e, 0x55, 0xba, 0x9d, 0xd7, 0x24, 0x25, 0x79, 0xf2, 0x99,
0x3b, 0x64, 0xe1, 0x6e, 0xf3, 0xdc, 0xab, 0x95, 0xaf, 0xd4, 0x97, 0x33, 0x3d, 0x8f, 0xa1, 0x2f, 0x5f,
0xf3, 0x55, 0x16, 0x3e, 0x43, 0xce, 0x22, 0x4e, 0x0b, 0x0e, 0x65, 0xff, 0x02, 0xac, 0x8e, 0x5c, 0x7b,
0xe0, 0x94, 0x19, 0xc7, 0x85, 0xe0, 0xca, 0x54, 0x7d, 0x55, 0xa1, 0x2e, 0x2d, 0x20,
};
const uint8_t spake2p_N_p256[] = {
0x04, 0xd8, 0xbb, 0xd6, 0xc6, 0x39, 0xc6, 0x29, 0x37, 0xb0, 0x4d, 0x99, 0x7f, 0x38, 0xc3, 0x77, 0x07,
0x19, 0xc6, 0x29, 0xd7, 0x01, 0x4d, 0x49, 0xa2, 0x4b, 0x4f, 0x98, 0xba, 0xa1, 0x29, 0x2b, 0x49, 0x07,
0xd6, 0x0a, 0xa6, 0xbf, 0xad, 0xe4, 0x50, 0x08, 0xa6, 0x36, 0x33, 0x7f, 0x51, 0x68, 0xc6, 0x4d, 0x9b,
0xd3, 0x60, 0x34, 0x80, 0x8c, 0xd5, 0x64, 0x49, 0x0b, 0x1e, 0x65, 0x6e, 0xdb, 0xe7,
};
/**
* Spake2+ state machine to ensure proper execution of the protocol.
*/
enum class CHIP_SPAKE2P_STATE : uint8_t
{
PREINIT = 0, // Before any initialization
INIT, // First initialization
STARTED, // Prover & Verifier starts
R1, // Round one complete
R2, // Round two complete
KC, // Key confirmation complete
};
/**
* Spake2+ role.
*/
enum class CHIP_SPAKE2P_ROLE : uint8_t
{
VERIFIER = 0, // Accessory
PROVER = 1, // Commissioner
};
enum class SupportedECPKeyTypes : uint8_t
{
ECP256R1 = 0,
};
enum class ECPKeyTarget : uint8_t
{
ECDH = 0,
ECDSA = 1,
};
/** @brief Safely clears the first `len` bytes of memory area `buf`.
* @param buf Pointer to a memory buffer holding secret data that must be cleared.
* @param len Specifies secret data size in bytes.
**/
void ClearSecretData(uint8_t * buf, size_t len);
/**
* Helper for clearing a C array which auto-deduces the size.
*/
template <size_t N>
void ClearSecretData(uint8_t (&buf)[N])
{
ClearSecretData(buf, N);
}
/**
* @brief Constant-time buffer comparison
*
* This function implements constant time memcmp. It's good practice
* to use constant time functions for cryptographic functions.
*
* @param a Pointer to first buffer
* @param b Pointer to Second buffer
* @param n Number of bytes to compare
* @return true if `n` first bytes of both buffers are equal, false otherwise
*/
bool IsBufferContentEqualConstantTime(const void * a, const void * b, size_t n);
template <typename Sig>
class ECPKey
{
public:
virtual ~ECPKey() {}
virtual SupportedECPKeyTypes Type() const = 0;
virtual size_t Length() const = 0;
virtual bool IsUncompressed() const = 0;
virtual operator const uint8_t *() const = 0;
virtual operator uint8_t *() = 0;
virtual const uint8_t * ConstBytes() const = 0;
virtual uint8_t * Bytes() = 0;
virtual bool Matches(const ECPKey<Sig> & other) const
{
return (this->Length() == other.Length()) &&
IsBufferContentEqualConstantTime(this->ConstBytes(), other.ConstBytes(), this->Length());
}
virtual CHIP_ERROR ECDSA_validate_msg_signature(const uint8_t * msg, const size_t msg_length, const Sig & signature) const = 0;
virtual CHIP_ERROR ECDSA_validate_hash_signature(const uint8_t * hash, const size_t hash_length,
const Sig & signature) const = 0;
};
/**
* @brief Helper class for holding sensitive data that should be erased from memory after use.
*
* The sensitive data buffer is a variable-length, fixed-capacity buffer class that securely erases
* the contents of a buffer when the buffer is destroyed.
*/
template <size_t kCapacity>
class SensitiveDataBuffer
{
public:
~SensitiveDataBuffer()
{
// Sanitize after use
ClearSecretData(mBytes);
}
SensitiveDataBuffer & operator=(const SensitiveDataBuffer & other)
{
// Guard self assignment
if (this == &other)
return *this;
ClearSecretData(mBytes);
SetLength(other.Length());
::memcpy(Bytes(), other.ConstBytes(), other.Length());
return *this;
}
/**
* @brief Set current length of the buffer
* @return Error if new length is exceeds capacity of the buffer
*/
CHIP_ERROR SetLength(size_t length)
{
VerifyOrReturnError(length <= kCapacity, CHIP_ERROR_INVALID_ARGUMENT);
mLength = length;
return CHIP_NO_ERROR;
}
/**
* @brief Returns current length of the buffer
*/
size_t Length() const { return mLength; }
/**
* @brief Returns non-const pointer to start of the underlying buffer
*/
uint8_t * Bytes() { return &mBytes[0]; }
/**
* @brief Returns const pointer to start of the underlying buffer
*/
const uint8_t * ConstBytes() const { return &mBytes[0]; }
/**
* @brief Constructs span from the underlying buffer
*/
ByteSpan Span() const { return ByteSpan(ConstBytes(), Length()); }
/**
* @brief Returns capacity of the buffer
*/
static constexpr size_t Capacity() { return kCapacity; }
private:
uint8_t mBytes[kCapacity];
size_t mLength = 0;
};
/**
* @brief Helper class for holding fixed-sized sensitive data that should be erased from memory after use.
*
* The sensitive data buffer is a fixed-length, fixed-capacity buffer class that securely erases
* the contents of a buffer when the buffer is destroyed.
*/
template <size_t kCapacity>
class SensitiveDataFixedBuffer
{
public:
SensitiveDataFixedBuffer() = default;
constexpr explicit SensitiveDataFixedBuffer(const uint8_t (&rawValue)[kCapacity])
{
memcpy(&mBytes[0], &rawValue[0], kCapacity);
}
constexpr explicit SensitiveDataFixedBuffer(const FixedByteSpan<kCapacity> & value)
{
memcpy(&mBytes[0], value.data(), kCapacity);
}
~SensitiveDataFixedBuffer()
{
// Sanitize after use
ClearSecretData(mBytes);
}
/**
* @brief Returns fixed length of the buffer
*/
constexpr size_t Length() const { return kCapacity; }
/**
* @brief Returns non-const pointer to start of the underlying buffer
*/
uint8_t * Bytes() { return &mBytes[0]; }
/**
* @brief Returns const pointer to start of the underlying buffer
*/
const uint8_t * ConstBytes() const { return &mBytes[0]; }
/**
* @brief Constructs fixed span from the underlying buffer
*/
FixedByteSpan<kCapacity> Span() const { return FixedByteSpan<kCapacity>(mBytes); }
/**
* @brief Returns capacity of the buffer
*/
static constexpr size_t Capacity() { return kCapacity; }
private:
uint8_t mBytes[kCapacity];
};
using P256ECDSASignature = SensitiveDataBuffer<kMax_ECDSA_Signature_Length>;
using P256ECDHDerivedSecret = SensitiveDataBuffer<kMax_ECDH_Secret_Length>;
using IdentityProtectionKey = SensitiveDataFixedBuffer<CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES>;
using IdentityProtectionKeySpan = FixedByteSpan<Crypto::CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES>;
using AttestationChallenge = SensitiveDataFixedBuffer<CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES>;
class P256PublicKey : public ECPKey<P256ECDSASignature>
{
public:
P256PublicKey() {}
template <size_t N>
constexpr P256PublicKey(const uint8_t (&raw_value)[N])
{
static_assert(N == kP256_PublicKey_Length, "Can only array-initialize from proper bounds");
memcpy(&bytes[0], &raw_value[0], N);
}
template <size_t N>
constexpr P256PublicKey(const FixedByteSpan<N> & value)
{
static_assert(N == kP256_PublicKey_Length, "Can only initialize from proper sized byte span");
memcpy(&bytes[0], value.data(), N);
}
template <size_t N>
P256PublicKey & operator=(const FixedByteSpan<N> & value)
{
static_assert(N == kP256_PublicKey_Length, "Can only initialize from proper sized byte span");
memcpy(&bytes[0], value.data(), N);
return *this;
}
SupportedECPKeyTypes Type() const override { return SupportedECPKeyTypes::ECP256R1; }
size_t Length() const override { return kP256_PublicKey_Length; }
operator uint8_t *() override { return bytes; }
operator const uint8_t *() const override { return bytes; }
const uint8_t * ConstBytes() const override { return &bytes[0]; }
uint8_t * Bytes() override { return &bytes[0]; }
bool IsUncompressed() const override
{
constexpr uint8_t kUncompressedPointMarker = 0x04;
// SEC1 definition of an uncompressed point is (0x04 || X || Y) where X and Y are
// raw zero-padded big-endian large integers of the group size.
return (Length() == ((kP256_FE_Length * 2) + 1)) && (ConstBytes()[0] == kUncompressedPointMarker);
}
CHIP_ERROR ECDSA_validate_msg_signature(const uint8_t * msg, size_t msg_length,
const P256ECDSASignature & signature) const override;
CHIP_ERROR ECDSA_validate_hash_signature(const uint8_t * hash, size_t hash_length,
const P256ECDSASignature & signature) const override;
private:
uint8_t bytes[kP256_PublicKey_Length];
};
template <typename PK, typename Secret, typename Sig>
class ECPKeypair
{
public:
virtual ~ECPKeypair() {}
/** @brief Generate a new Certificate Signing Request (CSR).
* @param csr Newly generated CSR in DER format
* @param csr_length The caller provides the length of input buffer (csr). The function returns the actual length of generated
*CSR.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR NewCertificateSigningRequest(uint8_t * csr, size_t & csr_length) const = 0;
/**
* @brief A function to sign a msg using ECDSA
* @param msg Message that needs to be signed
* @param msg_length Length of message
* @param out_signature Buffer that will hold the output signature. The signature consists of: 2 EC elements (r and s),
* in raw <r,s> point form (see SEC1).
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR ECDSA_sign_msg(const uint8_t * msg, size_t msg_length, Sig & out_signature) const = 0;
/** @brief A function to derive a shared secret using ECDH
* @param remote_public_key Public key of remote peer with which we are trying to establish secure channel. remote_public_key is
* ASN.1 DER encoded as padded big-endian field elements as described in SEC 1: Elliptic Curve Cryptography
* [https://www.secg.org/sec1-v2.pdf]
* @param out_secret Buffer to write out secret into. This is a byte array representing the x coordinate of the shared secret.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR ECDH_derive_secret(const PK & remote_public_key, Secret & out_secret) const = 0;
virtual const PK & Pubkey() const = 0;
};
struct alignas(size_t) P256KeypairContext
{
uint8_t mBytes[kMAX_P256Keypair_Context_Size];
};
using P256SerializedKeypair = SensitiveDataBuffer<kP256_PublicKey_Length + kP256_PrivateKey_Length>;
class P256KeypairBase : public ECPKeypair<P256PublicKey, P256ECDHDerivedSecret, P256ECDSASignature>
{
public:
/**
* @brief Initialize the keypair.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR Initialize(ECPKeyTarget key_target) = 0;
/**
* @brief Serialize the keypair.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR Serialize(P256SerializedKeypair & output) const = 0;
/**
* @brief Deserialize the keypair.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR Deserialize(P256SerializedKeypair & input) = 0;
};
class P256Keypair : public P256KeypairBase
{
public:
P256Keypair() {}
~P256Keypair() override;
/**
* @brief Initialize the keypair.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR Initialize(ECPKeyTarget key_target) override;
/**
* @brief Serialize the keypair.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR Serialize(P256SerializedKeypair & output) const override;
/**
* @brief Deserialize the keypair.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR Deserialize(P256SerializedKeypair & input) override;
/**
* @brief Generate a new Certificate Signing Request (CSR).
* @param csr Newly generated CSR in DER format
* @param csr_length The caller provides the length of input buffer (csr). The function returns the actual length of generated
*CSR.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR NewCertificateSigningRequest(uint8_t * csr, size_t & csr_length) const override;
/**
* @brief A function to sign a msg using ECDSA
* @param msg Message that needs to be signed
* @param msg_length Length of message
* @param out_signature Buffer that will hold the output signature. The signature consists of: 2 EC elements (r and s),
* in raw <r,s> point form (see SEC1).
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR ECDSA_sign_msg(const uint8_t * msg, size_t msg_length, P256ECDSASignature & out_signature) const override;
/**
* @brief A function to derive a shared secret using ECDH
*
* This implements the CHIP_Crypto_ECDH(PrivateKey myPrivateKey, PublicKey theirPublicKey) cryptographic primitive
* from the specification, using this class's private key from `mKeypair` as `myPrivateKey` and the remote
* public key from `remote_public_key` as `theirPublicKey`.
*
* @param remote_public_key Public key of remote peer with which we are trying to establish secure channel. remote_public_key is
* ASN.1 DER encoded as padded big-endian field elements as described in SEC 1: Elliptic Curve Cryptography
* [https://www.secg.org/sec1-v2.pdf]
* @param out_secret Buffer to write out secret into. This is a byte array representing the x coordinate of the shared secret.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR ECDH_derive_secret(const P256PublicKey & remote_public_key, P256ECDHDerivedSecret & out_secret) const override;
/** @brief Return public key for the keypair.
**/
const P256PublicKey & Pubkey() const override { return mPublicKey; }
/** Release resources associated with this key pair */
void Clear();
protected:
P256PublicKey mPublicKey;
mutable P256KeypairContext mKeypair;
bool mInitialized = false;
};
using Symmetric128BitsKeyByteArray = uint8_t[CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES];
/**
* @brief Platform-specific Symmetric key handle
*
* The class represents a key used by the Matter stack either in the form of raw key material or key
* reference, depending on the platform. To achieve that, it contains an opaque context that can be
* cast to a concrete representation used by the given platform. Note that currently Matter uses
* 128-bit symmetric keys only.
*
* @note Symmetric128BitsKeyHandle is an abstract class to force child classes for each key handle type.
* Symmetric128BitsKeyHandle class implements all the necessary components for handles.
* Child classes only need to implement a constructor and delete all the copy operators.
*/
class Symmetric128BitsKeyHandle
{
public:
Symmetric128BitsKeyHandle(const Symmetric128BitsKeyHandle &) = delete;
Symmetric128BitsKeyHandle(Symmetric128BitsKeyHandle &&) = delete;
void operator=(const Symmetric128BitsKeyHandle &) = delete;
void operator=(Symmetric128BitsKeyHandle &&) = delete;
/**
* @brief Get internal context cast to the desired key representation
*/
template <class T>
const T & As() const
{
return *SafePointerCast<const T *>(&mContext);
}
/**
* @brief Get internal context cast to the desired, mutable key representation
*/
template <class T>
T & AsMutable()
{
return *SafePointerCast<T *>(&mContext);
}
protected:
Symmetric128BitsKeyHandle() = default;
~Symmetric128BitsKeyHandle() { ClearSecretData(mContext.mOpaque); }
private:
static constexpr size_t kContextSize = CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES;
struct alignas(uintptr_t) OpaqueContext
{
uint8_t mOpaque[kContextSize] = {};
} mContext;
};
/**
* @brief Platform-specific AES key handle
*/
class Aes128KeyHandle final : public Symmetric128BitsKeyHandle
{
public:
Aes128KeyHandle() = default;
Aes128KeyHandle(const Aes128KeyHandle &) = delete;
Aes128KeyHandle(Aes128KeyHandle &&) = delete;
void operator=(const Aes128KeyHandle &) = delete;
void operator=(Aes128KeyHandle &&) = delete;
};
/**
* @brief Platform-specific HMAC key handle
*/
class Hmac128KeyHandle final : public Symmetric128BitsKeyHandle
{
public:
Hmac128KeyHandle() = default;
Hmac128KeyHandle(const Hmac128KeyHandle &) = delete;
Hmac128KeyHandle(Hmac128KeyHandle &&) = delete;
void operator=(const Hmac128KeyHandle &) = delete;
void operator=(Hmac128KeyHandle &&) = delete;
};
/**
* @brief Convert a raw ECDSA signature to ASN.1 signature (per X9.62) as used by TLS libraries.
*
* Errors are:
* - CHIP_ERROR_INVALID_ARGUMENT on any argument being invalid (e.g. nullptr), wrong sizes,
* wrong or unsupported format,
* - CHIP_ERROR_BUFFER_TOO_SMALL on running out of space at runtime.
* - CHIP_ERROR_INTERNAL on any unexpected processing error.
*
* @param[in] fe_length_bytes Field Element length in bytes (e.g. 32 for P256 curve)
* @param[in] raw_sig Raw signature of <r,s> concatenated
* @param[out] out_asn1_sig ASN.1 DER signature format output buffer. Size must have space for at least
* kMax_ECDSA_X9Dot62_Asn1_Overhead. On CHIP_NO_ERROR, the out_asn1_sig buffer will be re-assigned
* to have the correct size based on variable-length output.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
*/
CHIP_ERROR EcdsaRawSignatureToAsn1(size_t fe_length_bytes, const ByteSpan & raw_sig, MutableByteSpan & out_asn1_sig);
/**
* @brief Convert an ASN.1 DER signature (per X9.62) as used by TLS libraries to SEC1 raw format
*
* Errors are:
* - CHIP_ERROR_INVALID_ARGUMENT on any argument being invalid (e.g. nullptr), wrong sizes,
* wrong or unsupported format,
* - CHIP_ERROR_BUFFER_TOO_SMALL on running out of space at runtime.
* - CHIP_ERROR_INTERNAL on any unexpected processing error.
*
* @param[in] fe_length_bytes Field Element length in bytes (e.g. 32 for P256 curve)
* @param[in] asn1_sig ASN.1 DER signature input
* @param[out] out_raw_sig Raw signature of <r,s> concatenated format output buffer. Size must be at
* least >= `2 * fe_length_bytes`. On CHIP_NO_ERROR, the out_raw_sig buffer will be re-assigned
* to have the correct size (2 * fe_length_bytes).
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
*/
CHIP_ERROR EcdsaAsn1SignatureToRaw(size_t fe_length_bytes, const ByteSpan & asn1_sig, MutableByteSpan & out_raw_sig);
/**
* @brief Utility to read a length field after a tag in a DER-encoded stream.
* @param[in] reader Reader instance from which the input will be read
* @param[out] length Length of the following element read from the stream
* @return CHIP_ERROR_INVALID_ARGUMENT or CHIP_ERROR_BUFFER_TOO_SMALL on error, CHIP_NO_ERROR otherwise
*/
CHIP_ERROR ReadDerLength(chip::Encoding::LittleEndian::Reader & reader, size_t & length);
/**
* @brief Utility to emit a DER-encoded INTEGER given a raw unsigned large integer
* in big-endian order. The `out_der_integer` span is updated to reflect the final
* variable length, including tag and length, and must have at least `kEmitDerIntegerOverhead`
* extra space in addition to the `raw_integer.size()`.
* @param[in] raw_integer Bytes of a large unsigned integer in big-endian, possibly including leading zeroes
* @param[out] out_der_integer Buffer to receive the DER-encoded integer
* @return Returns CHIP_ERROR_INVALID_ARGUMENT or CHIP_ERROR_BUFFER_TOO_SMALL on error, CHIP_NO_ERROR otherwise.
*/
CHIP_ERROR ConvertIntegerRawToDer(const ByteSpan & raw_integer, MutableByteSpan & out_der_integer);
/**
* @brief Utility to emit a DER-encoded INTEGER given a raw unsigned large integer
* in big-endian order. The `out_der_integer` span is updated to reflect the final
* variable length, excluding tag and length, and must have at least `kEmitDerIntegerWithoutTagOverhead`
* extra space in addition to the `raw_integer.size()`.
* @param[in] raw_integer Bytes of a large unsigned integer in big-endian, possibly including leading zeroes
* @param[out] out_der_integer Buffer to receive the DER-encoded integer
* @return Returns CHIP_ERROR_INVALID_ARGUMENT or CHIP_ERROR_BUFFER_TOO_SMALL on error, CHIP_NO_ERROR otherwise.
*/
CHIP_ERROR ConvertIntegerRawToDerWithoutTag(const ByteSpan & raw_integer, MutableByteSpan & out_der_integer);
/**
* @brief A function that implements AES-CCM encryption
*
* This implements the CHIP_Crypto_AEAD_GenerateEncrypt() cryptographic primitive
* from the specification. For an empty plaintext, the user of the API can provide
* an empty string, or a nullptr, and provide plaintext_length as 0. The output buffer,
* ciphertext can also be an empty string, or a nullptr for this case.
*
* @param plaintext Plaintext to encrypt
* @param plaintext_length Length of plain_text
* @param aad Additional authentication data
* @param aad_length Length of additional authentication data
* @param key Encryption key
* @param nonce Encryption nonce
* @param nonce_length Length of encryption nonce
* @param ciphertext Buffer to write ciphertext into. Caller must ensure this is large enough to hold the ciphertext
* @param tag Buffer to write tag into. Caller must ensure this is large enough to hold the tag
* @param tag_length Expected length of tag
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
* */
CHIP_ERROR AES_CCM_encrypt(const uint8_t * plaintext, size_t plaintext_length, const uint8_t * aad, size_t aad_length,
const Aes128KeyHandle & key, const uint8_t * nonce, size_t nonce_length, uint8_t * ciphertext,
uint8_t * tag, size_t tag_length);
/**
* @brief A function that implements AES-CCM decryption
*
* This implements the CHIP_Crypto_AEAD_DecryptVerify() cryptographic primitive
* from the specification. For an empty ciphertext, the user of the API can provide
* an empty string, or a nullptr, and provide ciphertext_length as 0. The output buffer,
* plaintext can also be an empty string, or a nullptr for this case.
*
* @param ciphertext Ciphertext to decrypt
* @param ciphertext_length Length of ciphertext
* @param aad Additional authentical data.
* @param aad_length Length of additional authentication data
* @param tag Tag to use to decrypt
* @param tag_length Length of tag
* @param key Decryption key
* @param nonce Encryption nonce
* @param nonce_length Length of encryption nonce
* @param plaintext Buffer to write plaintext into
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR AES_CCM_decrypt(const uint8_t * ciphertext, size_t ciphertext_length, const uint8_t * aad, size_t aad_length,
const uint8_t * tag, size_t tag_length, const Aes128KeyHandle & key, const uint8_t * nonce,
size_t nonce_length, uint8_t * plaintext);
/**
* @brief A function that implements AES-CTR encryption/decryption
*
* This implements the AES-CTR-Encrypt/Decrypt() cryptographic primitives per sections
* 3.7.1 and 3.7.2 of the specification. For an empty input, the user of the API
* can provide an empty string, or a nullptr, and provide input as 0.
* The output buffer can also be an empty string, or a nullptr for this case.
*
* @param input Input text to encrypt/decrypt
* @param input_length Length of ciphertext
* @param key Decryption key
* @param nonce Encryption nonce
* @param nonce_length Length of encryption nonce
* @param output Buffer to write output into
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR AES_CTR_crypt(const uint8_t * input, size_t input_length, const Aes128KeyHandle & key, const uint8_t * nonce,
size_t nonce_length, uint8_t * output);
/**
* @brief Generate a PKCS#10 CSR, usable for Matter, from a P256Keypair.
*
* This uses first principles ASN.1 encoding to avoid relying on the CHIPCryptoPAL backend
* itself, other than to provide an implementation of a P256Keypair * that supports
* at least `::Pubkey()` and `::ECDSA_sign_msg`. This allows using it with
* OS/Platform-bridged private key handling, without requiring a specific
* implementation of other bits like ASN.1.
*
* The CSR will have subject OU set to `CSA`. This is needed since omiting
* subject altogether often trips CSR parsing code. The profile at the CA can
* be configured to ignore CSR requested subject.
*
* @param keypair The key pair for which a CSR should be generated. Must not be null.
* @param csr_span Span to hold the resulting CSR. Must have size at least kMIN_CSR_Buffer_Size.
* Otherwise returns CHIP_ERROR_BUFFER_TOO_SMALL. It will get resized to
* actual size needed on success.
* @return Returns a CHIP_ERROR from P256Keypair or ASN.1 backend on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR GenerateCertificateSigningRequest(const P256Keypair * keypair, MutableByteSpan & csr_span);
/**
* @brief Common code to validate ASN.1 format/size of a CSR, used by VerifyCertificateSigningRequest.
*
* Ensures it's not obviously malformed and doesn't have trailing garbage.
*
* @param csr CSR in DER format
* @param csr_length The length of the CSR buffer
* @return CHIP_ERROR_UNSUPPORTED_CERT_FORMAT on invalid format, CHIP_NO_ERROR otherwise.
*/
CHIP_ERROR VerifyCertificateSigningRequestFormat(const uint8_t * csr, size_t csr_length);
/**
* @brief Verify the Certificate Signing Request (CSR). If successfully verified, it outputs the public key from the CSR.
*
* The CSR is valid if the format is correct, the signature validates with the embedded public
* key, and there is no trailing garbage data.
*
* @param csr CSR in DER format
* @param csr_length The length of the CSR
* @param pubkey The public key from the verified CSR
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR VerifyCertificateSigningRequest(const uint8_t * csr, size_t csr_length, P256PublicKey & pubkey);
/**
* @brief A function that implements SHA-256 hash
*
* This implements the CHIP_Crypto_Hash() cryptographic primitive
* in the the specification.
*
* @param data The data to hash
* @param data_length Length of the data
* @param out_buffer Pointer to buffer to write output into
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR Hash_SHA256(const uint8_t * data, size_t data_length, uint8_t * out_buffer);
/**
* @brief A function that implements SHA-1 hash
* @param data The data to hash
* @param data_length Length of the data
* @param out_buffer Pointer to buffer to write output into
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR Hash_SHA1(const uint8_t * data, size_t data_length, uint8_t * out_buffer);
/**
* @brief A class that defines stream based implementation of SHA-256 hash
* It's expected that the object of this class can be safely copied.
* All implementations must check for std::is_trivially_copyable.
**/
struct alignas(CHIP_CONFIG_SHA256_CONTEXT_ALIGN) HashSHA256OpaqueContext
{
uint8_t mOpaque[kMAX_Hash_SHA256_Context_Size];
};
class Hash_SHA256_stream
{
public:
Hash_SHA256_stream();
~Hash_SHA256_stream();
/**
* @brief Re-initialize digest computation to an empty context.
*
* @return CHIP_ERROR_INTERNAL on failure to initialize the context,
* CHIP_NO_ERROR otherwise.
*/
CHIP_ERROR Begin();
/**
* @brief Add some data to the digest computation, updating internal state.
*
* @param[in] data The span of bytes to include in the digest update process.
*
* @return CHIP_ERROR_INTERNAL on failure to ingest the data, CHIP_NO_ERROR otherwise.
*/
CHIP_ERROR AddData(const ByteSpan data);
/**
* @brief Get the intermediate padded digest for the current state of the stream.
*
* More data can be added before finish is called.
*
* @param[in,out] out_buffer Output buffer to receive the digest. `out_buffer` must
* be at least `kSHA256_Hash_Length` bytes long. The `out_buffer` size
* will be set to `kSHA256_Hash_Length` on success.
*
* @return CHIP_ERROR_INTERNAL on failure to compute the digest, CHIP_ERROR_BUFFER_TOO_SMALL
* if out_buffer is too small, CHIP_NO_ERROR otherwise.
*/
CHIP_ERROR GetDigest(MutableByteSpan & out_buffer);
/**
* @brief Finalize the stream digest computation, getting the final digest.
*
* @param[in,out] out_buffer Output buffer to receive the digest. `out_buffer` must
* be at least `kSHA256_Hash_Length` bytes long. The `out_buffer` size
* will be set to `kSHA256_Hash_Length` on success.
*
* @return CHIP_ERROR_INTERNAL on failure to compute the digest, CHIP_ERROR_BUFFER_TOO_SMALL
* if out_buffer is too small, CHIP_NO_ERROR otherwise.
*/
CHIP_ERROR Finish(MutableByteSpan & out_buffer);
/**
* @brief Clear-out internal digest data to avoid lingering the state.
*/
void Clear();
private:
HashSHA256OpaqueContext mContext;
};
class HKDF_sha
{
public:
HKDF_sha() {}
virtual ~HKDF_sha() {}
/**
* @brief A function that implements SHA-256 based HKDF
*
* This implements the CHIP_Crypto_KDF() cryptographic primitive
* in the the specification.
*
* Error values are:
* - CHIP_ERROR_INVALID_ARGUMENT: for any bad arguments or nullptr input on
* any pointer.
* - CHIP_ERROR_INTERNAL: for any unexpected error arising in the underlying
* cryptographic layers.
*
* @param secret The secret to use as the key to the HKDF
* @param secret_length Length of the secret
* @param salt Optional salt to use as input to the HKDF
* @param salt_length Length of the salt
* @param info Optional info to use as input to the HKDF
* @param info_length Length of the info
* @param out_buffer Pointer to buffer to write output into.
* @param out_length Size of the underlying out_buffer. That length of output key material will be generated in out_buffer.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR HKDF_SHA256(const uint8_t * secret, size_t secret_length, const uint8_t * salt, size_t salt_length,
const uint8_t * info, size_t info_length, uint8_t * out_buffer, size_t out_length);
};
class HMAC_sha
{
public:
HMAC_sha() {}
virtual ~HMAC_sha() {}
/**
* @brief A function that implements SHA-256 based HMAC per FIPS1981.
*
* This implements the CHIP_Crypto_HMAC() cryptographic primitive
* in the the specification.
*
* The `out_length` must be at least kSHA256_Hash_Length, and only
* kSHA256_Hash_Length bytes are written to out_buffer.
*
* Error values are:
* - CHIP_ERROR_INVALID_ARGUMENT: for any bad arguments or nullptr input on
* any pointer.
* - CHIP_ERROR_INTERNAL: for any unexpected error arising in the underlying
* cryptographic layers.
*
* @param key The key to use for the HMAC operation
* @param key_length Length of the key
* @param message Message over which to compute the HMAC
* @param message_length Length of the message over which to compute the HMAC
* @param out_buffer Pointer to buffer into which to write the output.
* @param out_length Underlying size of the `out_buffer`.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR HMAC_SHA256(const uint8_t * key, size_t key_length, const uint8_t * message, size_t message_length,
uint8_t * out_buffer, size_t out_length);
/**
* @brief A function that implements SHA-256 based HMAC per FIPS1981.
*
* This implements the CHIP_Crypto_HMAC() cryptographic primitive
* in the the specification.
*
* The `out_length` must be at least kSHA256_Hash_Length, and only
* kSHA256_Hash_Length bytes are written to out_buffer.
*
* Error values are:
* - CHIP_ERROR_INVALID_ARGUMENT: for any bad arguments or nullptr input on
* any pointer.
* - CHIP_ERROR_INTERNAL: for any unexpected error arising in the underlying
* cryptographic layers.
*
* @param key The HMAC Key handle to use for the HMAC operation
* @param message Message over which to compute the HMAC
* @param message_length Length of the message over which to compute the HMAC
* @param out_buffer Pointer to buffer into which to write the output.
* @param out_length Underlying size of the `out_buffer`.
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR HMAC_SHA256(const Hmac128KeyHandle & key, const uint8_t * message, size_t message_length,
uint8_t * out_buffer, size_t out_length);
};
/**
* @brief A cryptographically secure random number generator based on NIST SP800-90A
* @param out_buffer Buffer into which to write random bytes
* @param out_length Number of random bytes to generate
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR DRBG_get_bytes(uint8_t * out_buffer, size_t out_length);
/** @brief Entropy callback function
* @param data Callback-specific data pointer
* @param output Output data to fill
* @param len Length of output buffer
* @param olen The actual amount of data that was written to output buffer
* @return 0 if success
*/
typedef int (*entropy_source)(void * data, uint8_t * output, size_t len, size_t * olen);
/** @brief A function to add entropy sources to crypto library
*
* This function can be called multiple times to add multiple entropy sources. However,
* once the entropy source is added, it cannot be removed. Please make sure that the
* entropy source is valid for the lifetime of the application. Also, make sure that the
* same entropy source is not added multiple times, e.g.: by calling this function
* in class constructor or initialization function.
*
* @param fn_source Function pointer to the entropy source
* @param p_source Data that should be provided when fn_source is called
* @param threshold Minimum required from source before entropy is released
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR add_entropy_source(entropy_source fn_source, void * p_source, size_t threshold);
class PBKDF2_sha256
{
public:
PBKDF2_sha256() {}
virtual ~PBKDF2_sha256() {}
/** @brief Function to derive key using password. SHA256 hashing algorithm is used for calculating hmac.
* @param password password used for key derivation
* @param plen length of buffer containing password
* @param salt salt to use as input to the KDF
* @param slen length of salt
* @param iteration_count number of iterations to run
* @param key_length length of output key
* @param output output buffer where the key will be written
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR pbkdf2_sha256(const uint8_t * password, size_t plen, const uint8_t * salt, size_t slen,
unsigned int iteration_count, uint32_t key_length, uint8_t * output);
};
/**
* The below class implements the draft 01 version of the Spake2+ protocol as
* defined in https://www.ietf.org/id/draft-bar-cfrg-spake2plus-01.html.
*
* The following describes the protocol flows:
*
* Commissioner Accessory
* ------------ ---------
*
* Init
* BeginProver
* ComputeRoundOne ------------->
* Init
* BeginVerifier
* /- ComputeRoundOne
* <------------- ComputeRoundTwo
* ComputeRoundTwo ------------->
* KeyConfirm KeyConfirm
* GetKeys GetKeys
*
**/
class Spake2p
{
public:
Spake2p(size_t fe_size, size_t point_size, size_t hash_size);
virtual ~Spake2p() {}
/**
* @brief Initialize Spake2+ with some context specific information.
*
* @param context The context is arbitrary but should include information about the
* protocol being run, contain the transcript for negotiation, include
* the PKBDF parameters, etc.
* @param context_len The length of the context.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR Init(const uint8_t * context, size_t context_len);
/**
* @brief Free Spake2+ underlying objects.
**/
virtual void Clear() = 0;
/**
* @brief Start the Spake2+ process as a verifier (i.e. an accessory being provisioned).
*
* @param my_identity The verifier identity. May be NULL if identities are not established.
* @param my_identity_len The verifier identity length.
* @param peer_identity The peer identity. May be NULL if identities are not established.
* @param peer_identity_len The peer identity length.
* @param w0in The input w0 (a parameter baked into the device or computed with ComputeW0).
* @param w0in_len The input w0 length.
* @param Lin The input L (a parameter baked into the device or computed with ComputeL).
* @param Lin_len The input L length.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR BeginVerifier(const uint8_t * my_identity, size_t my_identity_len, const uint8_t * peer_identity,
size_t peer_identity_len, const uint8_t * w0in, size_t w0in_len, const uint8_t * Lin,
size_t Lin_len);
/**
* @brief Start the Spake2+ process as a prover (i.e. a commissioner).
*
* @param my_identity The prover identity. May be NULL if identities are not established.
* @param my_identity_len The prover identity length.
* @param peer_identity The peer identity. May be NULL if identities are not established.
* @param peer_identity_len The peer identity length.
* @param w0in The input w0 (an output from the PBKDF).
* @param w0in_len The input w0 length.
* @param w1in The input w1 (an output from the PBKDF).
* @param w1in_len The input w1 length.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR BeginProver(const uint8_t * my_identity, size_t my_identity_len, const uint8_t * peer_identity,
size_t peer_identity_len, const uint8_t * w0in, size_t w0in_len, const uint8_t * w1in,
size_t w1in_len);
/**
* @brief Compute the first round of the protocol.
*
* @param pab X value from commissioner.
* @param pab_len X length.
* @param out The output first round Spake2+ contribution.
* @param out_len The output first round Spake2+ contribution length.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR ComputeRoundOne(const uint8_t * pab, size_t pab_len, uint8_t * out, size_t * out_len);
/**
* @brief Compute the second round of the protocol.
*
* @param in The peer first round Spake2+ contribution.
* @param in_len The peer first round Spake2+ contribution length.
* @param out The output second round Spake2+ contribution.
* @param out_len The output second round Spake2+ contribution length.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR ComputeRoundTwo(const uint8_t * in, size_t in_len, uint8_t * out, size_t * out_len);
/**
* @brief Confirm that each party computed the same keys.
*
* @param in The peer second round Spake2+ contribution.
* @param in_len The peer second round Spake2+ contribution length.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR KeyConfirm(const uint8_t * in, size_t in_len);
/**
* @brief Return the shared secret.
*
* @param out The output secret.
* @param out_len The output secret length.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
CHIP_ERROR GetKeys(uint8_t * out, size_t * out_len);
CHIP_ERROR InternalHash(const uint8_t * in, size_t in_len);
CHIP_ERROR WriteMN();
CHIP_ERROR GenerateKeys();
/**
* @brief Load a field element.
*
* @param in The input big endian field element.
* @param in_len The size of the input buffer in bytes.
* @param fe A pointer to an initialized implementation dependant field element.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR FELoad(const uint8_t * in, size_t in_len, void * fe) = 0;
/**
* @brief Write a field element in big-endian format.
*
* @param fe The field element to write.
* @param out The output buffer.
* @param out_len The length of the output buffer.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR FEWrite(const void * fe, uint8_t * out, size_t out_len) = 0;
/**
* @brief Generate a field element.
*
* @param fe A pointer to an initialized implementation dependant field element.
*
* @note The implementation must generate a random element from [0, q) where q is the curve order.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR FEGenerate(void * fe) = 0;
/**
* @brief Multiply two field elements, fer = fe1 * fe2.
*
* @param fer A pointer to an initialized implementation dependant field element.
* @param fe1 A pointer to an initialized implementation dependant field element.
* @param fe2 A pointer to an initialized implementation dependant field element.
*
* @note The result must be a field element (i.e. reduced by the curve order).
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR FEMul(void * fer, const void * fe1, const void * fe2) = 0;
/**
* @brief Load a point from 0x04 || X || Y format
*
* @param in Input buffer
* @param in_len Input buffer length
* @param R A pointer to an initialized implementation dependant point.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR PointLoad(const uint8_t * in, size_t in_len, void * R) = 0;
/**
* @brief Write a point in 0x04 || X || Y format
*
* @param R A pointer to an initialized implementation dependant point.
* @param out Output buffer
* @param out_len Length of the output buffer
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR PointWrite(const void * R, uint8_t * out, size_t out_len) = 0;
/**
* @brief Scalar multiplication, R = fe1 * P1.
*
* @param R Resultant point
* @param P1 Input point
* @param fe1 Input field element.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR PointMul(void * R, const void * P1, const void * fe1) = 0;
/**
* @brief Scalar multiplication with addition, R = fe1 * P1 + fe2 * P2.
*
* @param R Resultant point
* @param P1 Input point
* @param fe1 Input field element.
* @param P2 Input point
* @param fe2 Input field element.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR PointAddMul(void * R, const void * P1, const void * fe1, const void * P2, const void * fe2) = 0;
/**
* @brief Point inversion.
*
* @param R Input/Output point to point_invert
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR PointInvert(void * R) = 0;
/**
* @brief Multiply a point by the curve cofactor.
*
* @param R Input/Output point to point_invert
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR PointCofactorMul(void * R) = 0;
/*
* @synopsis Check if a point is on the curve.
*
* @param R Input point to check.
*
* @return CHIP_NO_ERROR if the point is valid, CHIP_ERROR otherwise.
*/
virtual CHIP_ERROR PointIsValid(void * R) = 0;
/*
* @synopsis Compute w0sin mod p
*
* @param w0out Output field element (modulo p)
* @param w0_len Output field element length
* @param w1sin Input field element
* @param w1sin_len Input field element length
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR ComputeW0(uint8_t * w0out, size_t * w0_len, const uint8_t * w0sin, size_t w0sin_len) = 0;
/*
* @synopsis Compute w1in*G
*
* @param Lout Output point in 0x04 || X || Y format.
* @param L_len Output point length
* @param w1in Input field element
* @param w1in_len Input field element size
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR ComputeL(uint8_t * Lout, size_t * L_len, const uint8_t * w1in, size_t w1in_len) = 0;
void * M;
void * N;
const void * G;
void * X;
void * Y;
void * L;
void * Z;
void * V;
void * w0;
void * w1;
void * xy;
void * order;
void * tempbn;
protected:
/**
* @brief Initialize underlying implementation curve, points, field elements, etc.
*
* @details The implementation needs to:
* 1. Initialize each of the points below and set the relevant pointers on the class:
* a. M
* b. N
* c. G
* d. X
* e. Y
* f. L
* g. Z
* h. V
*
* As an example:
* this.M = implementation_alloc_point();
* 2. Initialize each of the field elements below and set the relevant pointers on the class:
* a. w0
* b. w1
* c. xy
* d. tempbn
* 3. The hashing context should be initialized
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR InitImpl() = 0;
/**
* @brief Hash in_len bytes of in into the internal hash context.
*
* @param in The input buffer.
* @param in_len Size of the input buffer in bytes.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR Hash(const uint8_t * in, size_t in_len) = 0;
/**
* @brief Return the hash.
*
* @param out_span Output buffer. The size available must be >= the hash size. It gets resized
* to hash size on success.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR HashFinalize(MutableByteSpan & out_span) = 0;
/**
* @brief Generate a message authentication code.
*
* @param key The MAC key buffer.
* @param key_len The size of the MAC key in bytes.
* @param in The input buffer.
* @param in_len The size of the input data to MAC in bytes.
* @param out_span The output MAC buffer span. Size must be >= the hash_size. Output size is updated to fit on success.
*
* @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
**/
virtual CHIP_ERROR Mac(const uint8_t * key, size_t key_len, const uint8_t * in, size_t in_len, MutableByteSpan & out_span) = 0;
/**
* @brief Verify a message authentication code.
*
* @param key The MAC key buffer.
* @param key_len The size of the MAC key in bytes.
* @param mac The input MAC buffer.
* @param mac_len The size of the MAC in bytes.
* @param in The input buffer to verify.
* @param in_len The size of the input data to verify in bytes.
*
* @return Returns a CHIP_ERROR when the MAC doesn't validate, CHIP_NO_ERROR otherwise.
**/
virtual CHIP_ERROR MacVerify(const uint8_t * key, size_t key_len, const uint8_t * mac, size_t mac_len, const uint8_t * in,
size_t in_len) = 0;
/**
* @brief Derive an key of length out_len.
*
* @param ikm The input key material buffer.
* @param ikm_len The input key material length.
* @param salt The optional salt. This may be NULL.
* @param salt_len The size of the salt in bytes.
* @param info The info.
* @param info_len The size of the info in bytes.
* @param out The output key
* @param out_len The output key length
*
* @return Returns a CHIP_ERROR when the MAC doesn't validate, CHIP_NO_ERROR otherwise.
**/
virtual CHIP_ERROR KDF(const uint8_t * ikm, size_t ikm_len, const uint8_t * salt, size_t salt_len, const uint8_t * info,
size_t info_len, uint8_t * out, size_t out_len) = 0;
CHIP_SPAKE2P_ROLE role;
CHIP_SPAKE2P_STATE state = CHIP_SPAKE2P_STATE::PREINIT;
size_t fe_size;
size_t hash_size;
size_t point_size;
uint8_t Kcab[kMAX_Hash_Length];
uint8_t Kae[kMAX_Hash_Length];
uint8_t * Kca;
uint8_t * Kcb;
uint8_t * Ka;
uint8_t * Ke;
};
struct alignas(size_t) Spake2pOpaqueContext
{
uint8_t mOpaque[kMAX_Spake2p_Context_Size];
};
class Spake2p_P256_SHA256_HKDF_HMAC : public Spake2p
{
public:
Spake2p_P256_SHA256_HKDF_HMAC() : Spake2p(kP256_FE_Length, kP256_Point_Length, kSHA256_Hash_Length)
{
memset(&mSpake2pContext, 0, sizeof(mSpake2pContext));
}
~Spake2p_P256_SHA256_HKDF_HMAC() override { Spake2p_P256_SHA256_HKDF_HMAC::Clear(); }
void Clear() override;
CHIP_ERROR Mac(const uint8_t * key, size_t key_len, const uint8_t * in, size_t in_len, MutableByteSpan & out_span) override;
CHIP_ERROR MacVerify(const uint8_t * key, size_t key_len, const uint8_t * mac, size_t mac_len, const uint8_t * in,
size_t in_len) override;
CHIP_ERROR FELoad(const uint8_t * in, size_t in_len, void * fe) override;
CHIP_ERROR FEWrite(const void * fe, uint8_t * out, size_t out_len) override;
CHIP_ERROR FEGenerate(void * fe) override;
CHIP_ERROR FEMul(void * fer, const void * fe1, const void * fe2) override;
CHIP_ERROR PointLoad(const uint8_t * in, size_t in_len, void * R) override;
CHIP_ERROR PointWrite(const void * R, uint8_t * out, size_t out_len) override;
CHIP_ERROR PointMul(void * R, const void * P1, const void * fe1) override;
CHIP_ERROR PointAddMul(void * R, const void * P1, const void * fe1, const void * P2, const void * fe2) override;
CHIP_ERROR PointInvert(void * R) override;
CHIP_ERROR PointCofactorMul(void * R) override;
CHIP_ERROR PointIsValid(void * R) override;
CHIP_ERROR ComputeW0(uint8_t * w0out, size_t * w0_len, const uint8_t * w0sin, size_t w0sin_len) override;
CHIP_ERROR ComputeL(uint8_t * Lout, size_t * L_len, const uint8_t * w1in, size_t w1in_len) override;
protected:
CHIP_ERROR InitImpl() override;
CHIP_ERROR Hash(const uint8_t * in, size_t in_len) override;
CHIP_ERROR HashFinalize(MutableByteSpan & out_span) override;
CHIP_ERROR KDF(const uint8_t * secret, size_t secret_length, const uint8_t * salt, size_t salt_length, const uint8_t * info,
size_t info_length, uint8_t * out, size_t out_length) override;
private:
CHIP_ERROR InitInternal();
Hash_SHA256_stream sha256_hash_ctx;
Spake2pOpaqueContext mSpake2pContext;
};
/**
* @brief Class used for verifying PASE secure sessions.
**/
class Spake2pVerifier
{
public:
uint8_t mW0[kP256_FE_Length];
uint8_t mL[kP256_Point_Length];
CHIP_ERROR Serialize(MutableByteSpan & outSerialized) const;
CHIP_ERROR Deserialize(const ByteSpan & inSerialized);
/**
* @brief Generate the Spake2+ verifier.
*
* @param pbkdf2IterCount Iteration count for PBKDF2 function
* @param salt Salt to be used for Spake2+ operation
* @param setupPin Provided setup PIN (passcode)
*
* @return CHIP_ERROR The result of Spake2+ verifier generation
*/
CHIP_ERROR Generate(uint32_t pbkdf2IterCount, const ByteSpan & salt, uint32_t setupPin);
/**
* @brief Compute the initiator values (w0, w1) used for PAKE input.
*
* @param pbkdf2IterCount Iteration count for PBKDF2 function
* @param salt Salt to be used for Spake2+ operation
* @param setupPin Provided setup PIN (passcode)
* @param ws The output pair (w0, w1) stored sequentially
* @param ws_len The output length
*
* @return CHIP_ERROR The result from running PBKDF2
*/
static CHIP_ERROR ComputeWS(uint32_t pbkdf2IterCount, const ByteSpan & salt, uint32_t setupPin, uint8_t * ws, uint32_t ws_len);
};
/**
* @brief Serialized format of the Spake2+ Verifier components.
*
* This is used when the Verifier should be presented in a serialized form.
* For example, when it is generated using PBKDF function, when stored in the
* memory or when sent over the wire.
* The serialized format is concatentation of 'W0' and 'L' verifier components:
* { Spake2pVerifier.mW0[kP256_FE_Length], Spake2pVerifier.mL[kP256_Point_Length] }
**/
typedef uint8_t Spake2pVerifierSerialized[kSpake2p_VerifierSerialized_Length];
/**
* @brief Compute the compressed fabric identifier used for operational discovery service
* records from a Node's root public key and Fabric ID. On success, out_compressed_fabric_id
* will have a size of exactly kCompressedFabricIdentifierSize.
*
* Errors are:
* - CHIP_ERROR_INVALID_ARGUMENT if root_public_key is invalid
* - CHIP_ERROR_BUFFER_TOO_SMALL if out_compressed_fabric_id is too small for serialization
* - CHIP_ERROR_INTERNAL on any unexpected crypto or data conversion errors.
*
* @param[in] root_public_key The root public key associated with the node's fabric
* @param[in] fabric_id The fabric ID associated with the node's fabric
* @param[out] out_compressed_fabric_id Span where output will be written. Its size must be >= kCompressedFabricIdentifierSize.
* @returns a CHIP_ERROR (see above) on failure or CHIP_NO_ERROR otherwise.
*/
CHIP_ERROR GenerateCompressedFabricId(const Crypto::P256PublicKey & root_public_key, uint64_t fabric_id,
MutableByteSpan & out_compressed_fabric_id);
/**
* @brief Compute the compressed fabric identifier used for operational discovery service
* records from a Node's root public key and Fabric ID. This is a conveniance
* overload that writes to a uint64_t (CompressedFabricId) type.
*
* @param[in] rootPublicKey The root public key associated with the node's fabric
* @param[in] fabricId The fabric ID associated with the node's fabric
* @param[out] compressedFabricId output location for compressed fabric ID
* @returns a CHIP_ERROR on failure or CHIP_NO_ERROR otherwise.
*/
CHIP_ERROR GenerateCompressedFabricId(const Crypto::P256PublicKey & rootPublicKey, uint64_t fabricId,
uint64_t & compressedFabricId);
enum class CertificateChainValidationResult
{
kSuccess = 0,
kRootFormatInvalid = 100,
kRootArgumentInvalid = 101,
kICAFormatInvalid = 200,
kICAArgumentInvalid = 201,
kLeafFormatInvalid = 300,
kLeafArgumentInvalid = 301,
kChainInvalid = 400,
kNoMemory = 500,
kInternalFrameworkError = 600,
};
CHIP_ERROR ValidateCertificateChain(const uint8_t * rootCertificate, size_t rootCertificateLen, const uint8_t * caCertificate,
size_t caCertificateLen, const uint8_t * leafCertificate, size_t leafCertificateLen,
CertificateChainValidationResult & result);
enum class AttestationCertType
{
kPAA = 0,
kPAI = 1,
kDAC = 2,
};
CHIP_ERROR VerifyAttestationCertificateFormat(const ByteSpan & cert, AttestationCertType certType);
/**
* @brief Validate notBefore timestamp of a certificate (candidateCertificate) against validity period of the
* issuer certificate (issuerCertificate).
*
* Errors are:
* - CHIP_ERROR_CERT_EXPIRED if the candidateCertificate timestamp does not satisfy the issuerCertificate's timestamp.
* - CHIP_ERROR_INVALID_ARGUMENT when passing an invalid argument.
* - CHIP_ERROR_INTERNAL on any unexpected crypto or data conversion errors.
*
* @param candidateCertificate A DER Certificate ByteSpan those notBefore timestamp to be evaluated.
* @param issuerCertificate A DER Certificate ByteSpan used to evaluate validity timestamp of the candidateCertificate.
*
* @returns a CHIP_ERROR (see above) on failure or CHIP_NO_ERROR otherwise.
**/
CHIP_ERROR IsCertificateValidAtIssuance(const ByteSpan & candidateCertificate, const ByteSpan & issuerCertificate);
/**
* @brief Validate a certificate's validity date against current time.
*
* Errors are:
* - CHIP_ERROR_CERT_EXPIRED if the certificate has expired.
* - CHIP_ERROR_INVALID_ARGUMENT when passing an invalid argument.
* - CHIP_ERROR_INTERNAL on any unexpected crypto or data conversion errors.
*
* @param certificate A DER Certificate ByteSpan used as the validity reference to be checked against current time.
*
* @returns a CHIP_ERROR (see above) on failure or CHIP_NO_ERROR otherwise.
**/
CHIP_ERROR IsCertificateValidAtCurrentTime(const ByteSpan & certificate);
CHIP_ERROR ExtractPubkeyFromX509Cert(const ByteSpan & certificate, Crypto::P256PublicKey & pubkey);
/**
* @brief Extracts the Subject Key Identifier from an X509 Certificate.
**/
CHIP_ERROR ExtractSKIDFromX509Cert(const ByteSpan & certificate, MutableByteSpan & skid);
/**
* @brief Extracts the Authority Key Identifier from an X509 Certificate.
**/
CHIP_ERROR ExtractAKIDFromX509Cert(const ByteSpan & certificate, MutableByteSpan & akid);
/**
* @brief Extracts the CRL Distribution Point (CDP) extension from an X509 ASN.1 Encoded Certificate.
* The returned value only covers the URI of the CDP. Only a single URI distribution point
* GeneralName is supported, and only those that start with "http://" and "https://".
*
* @returns CHIP_ERROR_NOT_FOUND if not found or wrong format.
* CHIP_NO_ERROR otherwise.
**/
CHIP_ERROR ExtractCRLDistributionPointURIFromX509Cert(const ByteSpan & certificate, MutableCharSpan & cdpurl);
/**
* @brief Extracts the CRL Distribution Point (CDP) extension's cRLIssuer Name from an X509 ASN.1 Encoded Certificate.
* The value is copied into buffer in a raw ASN.1 X.509 format. This format should be directly comparable
* with the result of ExtractSubjectFromX509Cert().
*
* @returns CHIP_ERROR_NOT_FOUND if not found or wrong format.
* CHIP_NO_ERROR otherwise.
**/
CHIP_ERROR ExtractCDPExtensionCRLIssuerFromX509Cert(const ByteSpan & certificate, MutableByteSpan & crlIssuer);
/**
* @brief Extracts Serial Number from X509 Certificate.
**/
CHIP_ERROR ExtractSerialNumberFromX509Cert(const ByteSpan & certificate, MutableByteSpan & serialNumber);
/**
* @brief Extracts Subject Distinguished Name from X509 Certificate. The value is copied into buffer in a raw ASN.1 X.509 format.
**/
CHIP_ERROR ExtractSubjectFromX509Cert(const ByteSpan & certificate, MutableByteSpan & subject);
/**
* @brief Extracts Issuer Distinguished Name from X509 Certificate. The value is copied into buffer in a raw ASN.1 X.509 format.
**/
CHIP_ERROR ExtractIssuerFromX509Cert(const ByteSpan & certificate, MutableByteSpan & issuer);
/**
* @brief Checks for resigned version of the certificate in the list and returns it.
*
* The following conditions SHOULD be satisfied for the certificate to qualify as
* a resigned version of a reference certificate:
* - SKID of the candidate and the reference certificate should match.
* - SubjectDN of the candidate and the reference certificate should match.
*
* If no resigned version is found then reference certificate itself is returned.
*
* @param referenceCertificate A DER certificate.
* @param candidateCertificates A pointer to the list of DER Certificates, which should be searched
* for the resigned version of `referenceCertificate`.
* @param candidateCertificatesCount Number of certificates in the `candidateCertificates` list.
* @param outCertificate A reference to the certificate or it's resigned version if found.
* Note that it points to either `referenceCertificate` or one of
* `candidateCertificates`, but it doesn't copy data.
*
* @returns error if there is certificate parsing/format issue or CHIP_NO_ERROR otherwise.
**/
CHIP_ERROR ReplaceCertIfResignedCertFound(const ByteSpan & referenceCertificate, const ByteSpan * candidateCertificates,
size_t candidateCertificatesCount, ByteSpan & outCertificate);
/**
* Defines DN attribute types that can include endocing of VID/PID parameters.
*/
enum class DNAttrType
{
kUnspecified = 0,
kCommonName = 1,
kMatterVID = 2,
kMatterPID = 3,
};
/**
* @struct AttestationCertVidPid
*
* @brief
* A data structure representing Attestation Certificate VID and PID attributes.
*/
struct AttestationCertVidPid
{
Optional<VendorId> mVendorId;
Optional<uint16_t> mProductId;
bool Initialized() const { return (mVendorId.HasValue() || mProductId.HasValue()); }
};
/**
* @brief Extracts VID and PID attributes from the DN Attribute string.
* If attribute is not present the corresponding output value stays uninitialized.
*
* @return CHIP_ERROR_INVALID_ARGUMENT if wrong input is provided.
* CHIP_ERROR_WRONG_CERT_DN if encoding of kMatterVID and kMatterPID attributes is wrong.
* CHIP_NO_ERROR otherwise.
**/
CHIP_ERROR ExtractVIDPIDFromAttributeString(DNAttrType attrType, const ByteSpan & attr,
AttestationCertVidPid & vidpidFromMatterAttr, AttestationCertVidPid & vidpidFromCNAttr);
/**
* @brief Extracts VID and PID attributes from the Subject DN of an X509 Certificate.
* If attribute is not present the corresponding output value stays uninitialized.
**/
CHIP_ERROR ExtractVIDPIDFromX509Cert(const ByteSpan & x509Cert, AttestationCertVidPid & vidpid);
/**
* @brief The set of credentials needed to operate group message security with symmetric keys.
*/
typedef struct GroupOperationalCredentials
{
/// Validity start time in microseconds since 2000-01-01T00:00:00 UTC ("the Epoch")
uint64_t start_time;
/// Session Id
uint16_t hash;
/// Operational group key
uint8_t encryption_key[Crypto::CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES];
/// Privacy key
uint8_t privacy_key[Crypto::CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES];
} GroupOperationalCredentials;
/**
* @brief Opaque context used to protect a symmetric key. The key operations must
* be performed without exposing the protected key value.
*/
class SymmetricKeyContext
{
public:
/**
* @brief Returns the symmetric key hash
*
* TODO: Replace GetKeyHash() with DeriveGroupSessionId(SymmetricKeyContext &, uint16_t & session_id)
*
* @return Group Key Hash
*/
virtual uint16_t GetKeyHash() = 0;
virtual ~SymmetricKeyContext() = default;
/**
* @brief Perform the message encryption as described in 4.7.2. (Security Processing of Outgoing Messages)
* @param[in] plaintext Outgoing message payload.
* @param[in] aad Additional data (message header contents)
* @param[in] nonce Nonce (Security Flags | Message Counter | Source Node ID)
* @param[out] mic Outgoing Message Integrity Check
* @param[out] ciphertext Outgoing encrypted payload. Must be at least as big as plaintext. The same buffer may be used both
* for ciphertext, and plaintext.
* @return CHIP_ERROR
*/
virtual CHIP_ERROR MessageEncrypt(const ByteSpan & plaintext, const ByteSpan & aad, const ByteSpan & nonce,
MutableByteSpan & mic, MutableByteSpan & ciphertext) const = 0;
/**
* @brief Perform the message decryption as described in 4.7.3.(Security Processing of Incoming Messages)
* @param[in] ciphertext Incoming encrypted payload
* @param[in] aad Additional data (message header contents)
* @param[in] nonce Nonce (Security Flags | Message Counter | Source Node ID)
* @param[in] mic Incoming Message Integrity Check
* @param[out] plaintext Incoming message payload. Must be at least as big as ciphertext. The same buffer may be used both
* for plaintext, and ciphertext.
* @return CHIP_ERROR
*/
virtual CHIP_ERROR MessageDecrypt(const ByteSpan & ciphertext, const ByteSpan & aad, const ByteSpan & nonce,
const ByteSpan & mic, MutableByteSpan & plaintext) const = 0;
/**
* @brief Perform privacy encoding as described in 4.8.2. (Privacy Processing of Outgoing Messages)
* @param[in] input Message header to privacy encrypt
* @param[in] nonce Privacy Nonce = session_id | mic
* @param[out] output Message header obfuscated
* @return CHIP_ERROR
*/
virtual CHIP_ERROR PrivacyEncrypt(const ByteSpan & input, const ByteSpan & nonce, MutableByteSpan & output) const = 0;
/**
* @brief Perform privacy decoding as described in 4.8.3. (Privacy Processing of Incoming Messages)
* @param[in] input Message header to privacy decrypt
* @param[in] nonce Privacy Nonce = session_id | mic
* @param[out] output Message header deobfuscated
* @return CHIP_ERROR
*/
virtual CHIP_ERROR PrivacyDecrypt(const ByteSpan & input, const ByteSpan & nonce, MutableByteSpan & output) const = 0;
/**
* @brief Release resources such as dynamic memory used to allocate this instance of the SymmetricKeyContext
*/
virtual void Release() = 0;
};
/**
* @brief Derives the Operational Group Key using the Key Derivation Function (KDF) from the given epoch key.
* @param[in] epoch_key The epoch key. Must be CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
* @param[in] compressed_fabric_id The compressed fabric ID for the fabric (big endian byte string)
* @param[out] out_key Symmetric key used as the encryption key during message processing for group communication.
The buffer size must be at least CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
* @return Returns a CHIP_NO_ERROR on succcess, or CHIP_ERROR_INTERNAL if the provided key is invalid.
**/
CHIP_ERROR DeriveGroupOperationalKey(const ByteSpan & epoch_key, const ByteSpan & compressed_fabric_id, MutableByteSpan & out_key);
/**
* @brief Derives the Group Session ID from a given operational group key using
* the Key Derivation Function (Group Key Hash)
* @param[in] operational_key The operational group key. Must be CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
* @param[out] session_id Output of the Group Key Hash
* @return Returns a CHIP_NO_ERROR on succcess, or CHIP_ERROR_INVALID_ARGUMENT if the provided key is invalid.
**/
CHIP_ERROR DeriveGroupSessionId(const ByteSpan & operational_key, uint16_t & session_id);
/**
* @brief Derives the Privacy Group Key using the Key Derivation Function (KDF) from the given epoch key.
* @param[in] epoch_key The epoch key. Must be CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
* @param[out] out_key Symmetric key used as the privacy key during message processing for group communication.
* The buffer size must be at least CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
* @return Returns a CHIP_NO_ERROR on succcess, or CHIP_ERROR_INTERNAL if the provided key is invalid.
**/
CHIP_ERROR DeriveGroupPrivacyKey(const ByteSpan & epoch_key, MutableByteSpan & out_key);
/**
* @brief Derives the complete set of credentials needed for group security.
*
* This function will derive the Encryption Key, Group Key Hash (Session Id), and Privacy Key
* for the given Epoch Key and Compressed Fabric Id.
* @param[in] epoch_key The epoch key. Must be CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
* @param[in] compressed_fabric_id The compressed fabric ID for the fabric (big endian byte string)
* @param[out] operational_credentials The set of Symmetric keys used during message processing for group communication.
* @return Returns a CHIP_NO_ERROR on succcess, or CHIP_ERROR_INTERNAL if the provided key is invalid.
**/
CHIP_ERROR DeriveGroupOperationalCredentials(const ByteSpan & epoch_key, const ByteSpan & compressed_fabric_id,
GroupOperationalCredentials & operational_credentials);
} // namespace Crypto
} // namespace chip