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 /** * \file psa/crypto_sizes.h * * \brief PSA cryptography module: Mbed TLS buffer size macros * * \note This file may not be included directly. Applications must * include psa/crypto.h. * * This file contains the definitions of macros that are useful to * compute buffer sizes. The signatures and semantics of these macros * are standardized, but the definitions are not, because they depend on * the available algorithms and, in some cases, on permitted tolerances * on buffer sizes. * * In implementations with isolation between the application and the * cryptography module, implementers should take care to ensure that * the definitions that are exposed to applications match what the * module implements. * * Macros that compute sizes whose values do not depend on the * implementation are in crypto.h. */ /* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 * * 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. */ #ifndef PSA_CRYPTO_SIZES_H #define PSA_CRYPTO_SIZES_H /* Include the Mbed TLS configuration file, the way Mbed TLS does it * in each of its header files. */ #if !defined(MBEDTLS_CONFIG_FILE) #include "mbedtls/config.h" #else #include MBEDTLS_CONFIG_FILE #endif #define PSA_BITS_TO_BYTES(bits) (((bits) + 7) / 8) #define PSA_BYTES_TO_BITS(bytes) ((bytes) * 8) #define PSA_ROUND_UP_TO_MULTIPLE(block_size, length) \ (((length) + (block_size) - 1) / (block_size) * (block_size)) /** The size of the output of psa_hash_finish(), in bytes. * * This is also the hash size that psa_hash_verify() expects. * * \param alg A hash algorithm (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_HASH(\p alg) is true), or an HMAC algorithm * (#PSA_ALG_HMAC(\c hash_alg) where \c hash_alg is a * hash algorithm). * * \return The hash size for the specified hash algorithm. * If the hash algorithm is not recognized, return 0. * An implementation may return either 0 or the correct size * for a hash algorithm that it recognizes, but does not support. */ #define PSA_HASH_LENGTH(alg) \ ( \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_MD2 ? 16 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_MD4 ? 16 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_MD5 ? 16 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_RIPEMD160 ? 20 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_SHA_1 ? 20 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_SHA_224 ? 28 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_SHA_256 ? 32 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_SHA_384 ? 48 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_SHA_512 ? 64 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_SHA_512_224 ? 28 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_SHA_512_256 ? 32 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_SHA3_224 ? 28 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_SHA3_256 ? 32 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_SHA3_384 ? 48 : \ PSA_ALG_HMAC_GET_HASH(alg) == PSA_ALG_SHA3_512 ? 64 : \ 0) /** \def PSA_HASH_MAX_SIZE * * Maximum size of a hash. * * This macro must expand to a compile-time constant integer. This value * should be the maximum size of a hash supported by the implementation, * in bytes, and must be no smaller than this maximum. */ /* Note: for HMAC-SHA-3, the block size is 144 bytes for HMAC-SHA3-226, * 136 bytes for HMAC-SHA3-256, 104 bytes for SHA3-384, 72 bytes for * HMAC-SHA3-512. */ #if defined(MBEDTLS_SHA512_C) #define PSA_HASH_MAX_SIZE 64 #define PSA_HMAC_MAX_HASH_BLOCK_SIZE 128 #else #define PSA_HASH_MAX_SIZE 32 #define PSA_HMAC_MAX_HASH_BLOCK_SIZE 64 #endif /** \def PSA_MAC_MAX_SIZE * * Maximum size of a MAC. * * This macro must expand to a compile-time constant integer. This value * should be the maximum size of a MAC supported by the implementation, * in bytes, and must be no smaller than this maximum. */ /* All non-HMAC MACs have a maximum size that's smaller than the * minimum possible value of PSA_HASH_MAX_SIZE in this implementation. */ /* Note that the encoding of truncated MAC algorithms limits this value * to 64 bytes. */ #define PSA_MAC_MAX_SIZE PSA_HASH_MAX_SIZE /** The tag size for an AEAD algorithm, in bytes. * * \param alg An AEAD algorithm * (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_AEAD(\p alg) is true). * * \return The tag size for the specified algorithm. * If the AEAD algorithm does not have an identified * tag that can be distinguished from the rest of * the ciphertext, return 0. * If the AEAD algorithm is not recognized, return 0. * An implementation may return either 0 or a * correct size for an AEAD algorithm that it * recognizes, but does not support. */ #define PSA_AEAD_TAG_LENGTH(alg) \ (PSA_ALG_IS_AEAD(alg) ? \ (((alg) & PSA_ALG_AEAD_TAG_LENGTH_MASK) >> PSA_AEAD_TAG_LENGTH_OFFSET) : \ 0) /* The maximum size of an RSA key on this implementation, in bits. * This is a vendor-specific macro. * * Mbed TLS does not set a hard limit on the size of RSA keys: any key * whose parameters fit in a bignum is accepted. However large keys can * induce a large memory usage and long computation times. Unlike other * auxiliary macros in this file and in crypto.h, which reflect how the * library is configured, this macro defines how the library is * configured. This implementation refuses to import or generate an * RSA key whose size is larger than the value defined here. * * Note that an implementation may set different size limits for different * operations, and does not need to accept all key sizes up to the limit. */ #define PSA_VENDOR_RSA_MAX_KEY_BITS 4096 /* The maximum size of an ECC key on this implementation, in bits. * This is a vendor-specific macro. */ #if defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 521 #elif defined(MBEDTLS_ECP_DP_BP512R1_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 512 #elif defined(MBEDTLS_ECP_DP_CURVE448_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 448 #elif defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 384 #elif defined(MBEDTLS_ECP_DP_BP384R1_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 384 #elif defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 256 #elif defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 256 #elif defined(MBEDTLS_ECP_DP_BP256R1_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 256 #elif defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 255 #elif defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 224 #elif defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 224 #elif defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 192 #elif defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED) #define PSA_VENDOR_ECC_MAX_CURVE_BITS 192 #else #define PSA_VENDOR_ECC_MAX_CURVE_BITS 0 #endif /** This macro returns the maximum supported length of the PSK for the * TLS-1.2 PSK-to-MS key derivation * (#PSA_ALG_TLS12_PSK_TO_MS(\p hash_alg)). * * The maximum supported length does not depend on the chosen hash algorithm. * * Quoting RFC 4279, Sect 5.3: * TLS implementations supporting these ciphersuites MUST support * arbitrary PSK identities up to 128 octets in length, and arbitrary * PSKs up to 64 octets in length. Supporting longer identities and * keys is RECOMMENDED. * * Therefore, no implementation should define a value smaller than 64 * for #PSA_TLS12_PSK_TO_MS_PSK_MAX_SIZE. */ #define PSA_TLS12_PSK_TO_MS_PSK_MAX_SIZE 128 /** The maximum size of a block cipher supported by the implementation. */ #define PSA_BLOCK_CIPHER_BLOCK_MAX_SIZE 16 /** The size of the output of psa_mac_sign_finish(), in bytes. * * This is also the MAC size that psa_mac_verify_finish() expects. * * \warning This macro may evaluate its arguments multiple times or * zero times, so you should not pass arguments that contain * side effects. * * \param key_type The type of the MAC key. * \param key_bits The size of the MAC key in bits. * \param alg A MAC algorithm (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_MAC(\p alg) is true). * * \return The MAC size for the specified algorithm with * the specified key parameters. * \return 0 if the MAC algorithm is not recognized. * \return Either 0 or the correct size for a MAC algorithm that * the implementation recognizes, but does not support. * \return Unspecified if the key parameters are not consistent * with the algorithm. */ #define PSA_MAC_LENGTH(key_type, key_bits, alg) \ ((alg) & PSA_ALG_MAC_TRUNCATION_MASK ? PSA_MAC_TRUNCATED_LENGTH(alg) : \ PSA_ALG_IS_HMAC(alg) ? PSA_HASH_LENGTH(PSA_ALG_HMAC_GET_HASH(alg)) : \ PSA_ALG_IS_BLOCK_CIPHER_MAC(alg) ? PSA_BLOCK_CIPHER_BLOCK_LENGTH(key_type) : \ ((void)(key_type), (void)(key_bits), 0)) /** The maximum size of the output of psa_aead_encrypt(), in bytes. * * If the size of the ciphertext buffer is at least this large, it is * guaranteed that psa_aead_encrypt() will not fail due to an * insufficient buffer size. Depending on the algorithm, the actual size of * the ciphertext may be smaller. * * \param alg An AEAD algorithm * (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_AEAD(\p alg) is true). * \param plaintext_length Size of the plaintext in bytes. * * \return The AEAD ciphertext size for the specified * algorithm. * If the AEAD algorithm is not recognized, return 0. * An implementation may return either 0 or a * correct size for an AEAD algorithm that it * recognizes, but does not support. */ #define PSA_AEAD_ENCRYPT_OUTPUT_SIZE(alg, plaintext_length) \ (PSA_AEAD_TAG_LENGTH(alg) != 0 ? \ (plaintext_length) + PSA_AEAD_TAG_LENGTH(alg) : \ 0) /** The maximum size of the output of psa_aead_decrypt(), in bytes. * * If the size of the plaintext buffer is at least this large, it is * guaranteed that psa_aead_decrypt() will not fail due to an * insufficient buffer size. Depending on the algorithm, the actual size of * the plaintext may be smaller. * * \param alg An AEAD algorithm * (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_AEAD(\p alg) is true). * \param ciphertext_length Size of the plaintext in bytes. * * \return The AEAD ciphertext size for the specified * algorithm. * If the AEAD algorithm is not recognized, return 0. * An implementation may return either 0 or a * correct size for an AEAD algorithm that it * recognizes, but does not support. */ #define PSA_AEAD_DECRYPT_OUTPUT_SIZE(alg, ciphertext_length) \ (PSA_AEAD_TAG_LENGTH(alg) != 0 ? \ (ciphertext_length) - PSA_AEAD_TAG_LENGTH(alg) : \ 0) /** A sufficient output buffer size for psa_aead_update(). * * If the size of the output buffer is at least this large, it is * guaranteed that psa_aead_update() will not fail due to an * insufficient buffer size. The actual size of the output may be smaller * in any given call. * * \param alg An AEAD algorithm * (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_AEAD(\p alg) is true). * \param input_length Size of the input in bytes. * * \return A sufficient output buffer size for the specified * algorithm. * If the AEAD algorithm is not recognized, return 0. * An implementation may return either 0 or a * correct size for an AEAD algorithm that it * recognizes, but does not support. */ /* For all the AEAD modes defined in this specification, it is possible * to emit output without delay. However, hardware may not always be * capable of this. So for modes based on a block cipher, allow the * implementation to delay the output until it has a full block. */ #define PSA_AEAD_UPDATE_OUTPUT_SIZE(alg, input_length) \ (PSA_ALG_IS_AEAD_ON_BLOCK_CIPHER(alg) ? \ PSA_ROUND_UP_TO_MULTIPLE(PSA_BLOCK_CIPHER_BLOCK_MAX_SIZE, (input_length)) : \ (input_length)) /** A sufficient ciphertext buffer size for psa_aead_finish(). * * If the size of the ciphertext buffer is at least this large, it is * guaranteed that psa_aead_finish() will not fail due to an * insufficient ciphertext buffer size. The actual size of the output may * be smaller in any given call. * * \param alg An AEAD algorithm * (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_AEAD(\p alg) is true). * * \return A sufficient ciphertext buffer size for the * specified algorithm. * If the AEAD algorithm is not recognized, return 0. * An implementation may return either 0 or a * correct size for an AEAD algorithm that it * recognizes, but does not support. */ #define PSA_AEAD_FINISH_OUTPUT_SIZE(alg) \ (PSA_ALG_IS_AEAD_ON_BLOCK_CIPHER(alg) ? \ PSA_BLOCK_CIPHER_BLOCK_MAX_SIZE : \ 0) /** A sufficient plaintext buffer size for psa_aead_verify(). * * If the size of the plaintext buffer is at least this large, it is * guaranteed that psa_aead_verify() will not fail due to an * insufficient plaintext buffer size. The actual size of the output may * be smaller in any given call. * * \param alg An AEAD algorithm * (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_AEAD(\p alg) is true). * * \return A sufficient plaintext buffer size for the * specified algorithm. * If the AEAD algorithm is not recognized, return 0. * An implementation may return either 0 or a * correct size for an AEAD algorithm that it * recognizes, but does not support. */ #define PSA_AEAD_VERIFY_OUTPUT_SIZE(alg) \ (PSA_ALG_IS_AEAD_ON_BLOCK_CIPHER(alg) ? \ PSA_BLOCK_CIPHER_BLOCK_MAX_SIZE : \ 0) #define PSA_RSA_MINIMUM_PADDING_SIZE(alg) \ (PSA_ALG_IS_RSA_OAEP(alg) ? \ 2 * PSA_HASH_LENGTH(PSA_ALG_RSA_OAEP_GET_HASH(alg)) + 1 : \ 11 /*PKCS#1v1.5*/) /** * \brief ECDSA signature size for a given curve bit size * * \param curve_bits Curve size in bits. * \return Signature size in bytes. * * \note This macro returns a compile-time constant if its argument is one. */ #define PSA_ECDSA_SIGNATURE_SIZE(curve_bits) \ (PSA_BITS_TO_BYTES(curve_bits) * 2) /** Sufficient signature buffer size for psa_sign_hash(). * * This macro returns a sufficient buffer size for a signature using a key * of the specified type and size, with the specified algorithm. * Note that the actual size of the signature may be smaller * (some algorithms produce a variable-size signature). * * \warning This function may call its arguments multiple times or * zero times, so you should not pass arguments that contain * side effects. * * \param key_type An asymmetric key type (this may indifferently be a * key pair type or a public key type). * \param key_bits The size of the key in bits. * \param alg The signature algorithm. * * \return If the parameters are valid and supported, return * a buffer size in bytes that guarantees that * psa_sign_hash() will not fail with * #PSA_ERROR_BUFFER_TOO_SMALL. * If the parameters are a valid combination that is not supported * by the implementation, this macro shall return either a * sensible size or 0. * If the parameters are not valid, the * return value is unspecified. */ #define PSA_SIGN_OUTPUT_SIZE(key_type, key_bits, alg) \ (PSA_KEY_TYPE_IS_RSA(key_type) ? ((void)alg, PSA_BITS_TO_BYTES(key_bits)) : \ PSA_KEY_TYPE_IS_ECC(key_type) ? PSA_ECDSA_SIGNATURE_SIZE(key_bits) : \ ((void)alg, 0)) #define PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE \ PSA_ECDSA_SIGNATURE_SIZE(PSA_VENDOR_ECC_MAX_CURVE_BITS) /** \def PSA_SIGNATURE_MAX_SIZE * * Maximum size of an asymmetric signature. * * This macro must expand to a compile-time constant integer. This value * should be the maximum size of a signature supported by the implementation, * in bytes, and must be no smaller than this maximum. */ #define PSA_SIGNATURE_MAX_SIZE \ (PSA_BITS_TO_BYTES(PSA_VENDOR_RSA_MAX_KEY_BITS) > PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE ? \ PSA_BITS_TO_BYTES(PSA_VENDOR_RSA_MAX_KEY_BITS) : \ PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE) /** Sufficient output buffer size for psa_asymmetric_encrypt(). * * This macro returns a sufficient buffer size for a ciphertext produced using * a key of the specified type and size, with the specified algorithm. * Note that the actual size of the ciphertext may be smaller, depending * on the algorithm. * * \warning This function may call its arguments multiple times or * zero times, so you should not pass arguments that contain * side effects. * * \param key_type An asymmetric key type (this may indifferently be a * key pair type or a public key type). * \param key_bits The size of the key in bits. * \param alg The asymmetric encryption algorithm. * * \return If the parameters are valid and supported, return * a buffer size in bytes that guarantees that * psa_asymmetric_encrypt() will not fail with * #PSA_ERROR_BUFFER_TOO_SMALL. * If the parameters are a valid combination that is not supported * by the implementation, this macro shall return either a * sensible size or 0. * If the parameters are not valid, the * return value is unspecified. */ #define PSA_ASYMMETRIC_ENCRYPT_OUTPUT_SIZE(key_type, key_bits, alg) \ (PSA_KEY_TYPE_IS_RSA(key_type) ? \ ((void)alg, PSA_BITS_TO_BYTES(key_bits)) : \ 0) /** Sufficient output buffer size for psa_asymmetric_decrypt(). * * This macro returns a sufficient buffer size for a plaintext produced using * a key of the specified type and size, with the specified algorithm. * Note that the actual size of the plaintext may be smaller, depending * on the algorithm. * * \warning This function may call its arguments multiple times or * zero times, so you should not pass arguments that contain * side effects. * * \param key_type An asymmetric key type (this may indifferently be a * key pair type or a public key type). * \param key_bits The size of the key in bits. * \param alg The asymmetric encryption algorithm. * * \return If the parameters are valid and supported, return * a buffer size in bytes that guarantees that * psa_asymmetric_decrypt() will not fail with * #PSA_ERROR_BUFFER_TOO_SMALL. * If the parameters are a valid combination that is not supported * by the implementation, this macro shall return either a * sensible size or 0. * If the parameters are not valid, the * return value is unspecified. */ #define PSA_ASYMMETRIC_DECRYPT_OUTPUT_SIZE(key_type, key_bits, alg) \ (PSA_KEY_TYPE_IS_RSA(key_type) ? \ PSA_BITS_TO_BYTES(key_bits) - PSA_RSA_MINIMUM_PADDING_SIZE(alg) : \ 0) /* Maximum size of the ASN.1 encoding of an INTEGER with the specified * number of bits. * * This definition assumes that bits <= 2^19 - 9 so that the length field * is at most 3 bytes. The length of the encoding is the length of the * bit string padded to a whole number of bytes plus: * - 1 type byte; * - 1 to 3 length bytes; * - 0 to 1 bytes of leading 0 due to the sign bit. */ #define PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE(bits) \ ((bits) / 8 + 5) /* Maximum size of the export encoding of an RSA public key. * Assumes that the public exponent is less than 2^32. * * RSAPublicKey ::= SEQUENCE { * modulus INTEGER, -- n * publicExponent INTEGER } -- e * * - 4 bytes of SEQUENCE overhead; * - n : INTEGER; * - 7 bytes for the public exponent. */ #define PSA_KEY_EXPORT_RSA_PUBLIC_KEY_MAX_SIZE(key_bits) \ (PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE(key_bits) + 11) /* Maximum size of the export encoding of an RSA key pair. * Assumes thatthe public exponent is less than 2^32 and that the size * difference between the two primes is at most 1 bit. * * RSAPrivateKey ::= SEQUENCE { * version Version, -- 0 * modulus INTEGER, -- N-bit * publicExponent INTEGER, -- 32-bit * privateExponent INTEGER, -- N-bit * prime1 INTEGER, -- N/2-bit * prime2 INTEGER, -- N/2-bit * exponent1 INTEGER, -- N/2-bit * exponent2 INTEGER, -- N/2-bit * coefficient INTEGER, -- N/2-bit * } * * - 4 bytes of SEQUENCE overhead; * - 3 bytes of version; * - 7 half-size INTEGERs plus 2 full-size INTEGERs, * overapproximated as 9 half-size INTEGERS; * - 7 bytes for the public exponent. */ #define PSA_KEY_EXPORT_RSA_KEY_PAIR_MAX_SIZE(key_bits) \ (9 * PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE((key_bits) / 2 + 1) + 14) /* Maximum size of the export encoding of a DSA public key. * * SubjectPublicKeyInfo ::= SEQUENCE { * algorithm AlgorithmIdentifier, * subjectPublicKey BIT STRING } -- contains DSAPublicKey * AlgorithmIdentifier ::= SEQUENCE { * algorithm OBJECT IDENTIFIER, * parameters Dss-Parms } -- SEQUENCE of 3 INTEGERs * DSAPublicKey ::= INTEGER -- public key, Y * * - 3 * 4 bytes of SEQUENCE overhead; * - 1 + 1 + 7 bytes of algorithm (DSA OID); * - 4 bytes of BIT STRING overhead; * - 3 full-size INTEGERs (p, g, y); * - 1 + 1 + 32 bytes for 1 sub-size INTEGER (q <= 256 bits). */ #define PSA_KEY_EXPORT_DSA_PUBLIC_KEY_MAX_SIZE(key_bits) \ (PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE(key_bits) * 3 + 59) /* Maximum size of the export encoding of a DSA key pair. * * DSAPrivateKey ::= SEQUENCE { * version Version, -- 0 * prime INTEGER, -- p * subprime INTEGER, -- q * generator INTEGER, -- g * public INTEGER, -- y * private INTEGER, -- x * } * * - 4 bytes of SEQUENCE overhead; * - 3 bytes of version; * - 3 full-size INTEGERs (p, g, y); * - 2 * (1 + 1 + 32) bytes for 2 sub-size INTEGERs (q, x <= 256 bits). */ #define PSA_KEY_EXPORT_DSA_KEY_PAIR_MAX_SIZE(key_bits) \ (PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE(key_bits) * 3 + 75) /* Maximum size of the export encoding of an ECC public key. * * The representation of an ECC public key is: * - The byte 0x04; * - x_P as a ceiling(m/8)-byte string, big-endian; * - y_P as a ceiling(m/8)-byte string, big-endian; * - where m is the bit size associated with the curve. * * - 1 byte + 2 * point size. */ #define PSA_KEY_EXPORT_ECC_PUBLIC_KEY_MAX_SIZE(key_bits) \ (2 * PSA_BITS_TO_BYTES(key_bits) + 1) /* Maximum size of the export encoding of an ECC key pair. * * An ECC key pair is represented by the secret value. */ #define PSA_KEY_EXPORT_ECC_KEY_PAIR_MAX_SIZE(key_bits) \ (PSA_BITS_TO_BYTES(key_bits)) /** Sufficient output buffer size for psa_export_key() or * psa_export_public_key(). * * This macro returns a compile-time constant if its arguments are * compile-time constants. * * \warning This macro may evaluate its arguments multiple times or * zero times, so you should not pass arguments that contain * side effects. * * The following code illustrates how to allocate enough memory to export * a key by querying the key type and size at runtime. * \code{c} * psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; * psa_status_t status; * status = psa_get_key_attributes(key, &attributes); * if (status != PSA_SUCCESS) handle_error(...); * psa_key_type_t key_type = psa_get_key_type(&attributes); * size_t key_bits = psa_get_key_bits(&attributes); * size_t buffer_size = PSA_EXPORT_KEY_OUTPUT_SIZE(key_type, key_bits); * psa_reset_key_attributes(&attributes); * uint8_t *buffer = malloc(buffer_size); * if (buffer == NULL) handle_error(...); * size_t buffer_length; * status = psa_export_key(key, buffer, buffer_size, &buffer_length); * if (status != PSA_SUCCESS) handle_error(...); * \endcode * * \param key_type A supported key type. * \param key_bits The size of the key in bits. * * \return If the parameters are valid and supported, return * a buffer size in bytes that guarantees that * psa_export_key() or psa_export_public_key() will not fail with * #PSA_ERROR_BUFFER_TOO_SMALL. * If the parameters are a valid combination that is not supported * by the implementation, this macro shall return either a * sensible size or 0. * If the parameters are not valid, the * return value is unspecified. */ #define PSA_EXPORT_KEY_OUTPUT_SIZE(key_type, key_bits) \ (PSA_KEY_TYPE_IS_UNSTRUCTURED(key_type) ? PSA_BITS_TO_BYTES(key_bits) : \ (key_type) == PSA_KEY_TYPE_RSA_KEY_PAIR ? PSA_KEY_EXPORT_RSA_KEY_PAIR_MAX_SIZE(key_bits) : \ (key_type) == PSA_KEY_TYPE_RSA_PUBLIC_KEY ? PSA_KEY_EXPORT_RSA_PUBLIC_KEY_MAX_SIZE(key_bits) : \ (key_type) == PSA_KEY_TYPE_DSA_KEY_PAIR ? PSA_KEY_EXPORT_DSA_KEY_PAIR_MAX_SIZE(key_bits) : \ (key_type) == PSA_KEY_TYPE_DSA_PUBLIC_KEY ? PSA_KEY_EXPORT_DSA_PUBLIC_KEY_MAX_SIZE(key_bits) : \ PSA_KEY_TYPE_IS_ECC_KEY_PAIR(key_type) ? PSA_KEY_EXPORT_ECC_KEY_PAIR_MAX_SIZE(key_bits) : \ PSA_KEY_TYPE_IS_ECC_PUBLIC_KEY(key_type) ? PSA_KEY_EXPORT_ECC_PUBLIC_KEY_MAX_SIZE(key_bits) : \ 0) /** The default nonce size for an AEAD algorithm, in bytes. * * This macro can be used to allocate a buffer of sufficient size to * store the nonce output from #psa_aead_generate_nonce(). * * See also #PSA_AEAD_NONCE_MAX_SIZE. * * \note This is not the maximum size of nonce supported as input to #psa_aead_set_nonce(), * #psa_aead_encrypt() or #psa_aead_decrypt(), just the default size that is generated by * #psa_aead_generate_nonce(). * * \warning This macro may evaluate its arguments multiple times or * zero times, so you should not pass arguments that contain * side effects. * * \param key_type A symmetric key type that is compatible with algorithm \p alg. * * \param alg An AEAD algorithm (\c PSA_ALG_XXX value such that #PSA_ALG_IS_AEAD(\p alg) is true). * * \return The default nonce size for the specified key type and algorithm. * If the key type or AEAD algorithm is not recognized, * or the parameters are incompatible, return 0. * An implementation can return either 0 or a correct size for a key type * and AEAD algorithm that it recognizes, but does not support. */ #define PSA_AEAD_NONCE_LENGTH(key_type, alg) \ (PSA_BLOCK_CIPHER_BLOCK_LENGTH(key_type) == 16 && \ (PSA_ALG_AEAD_WITH_DEFAULT_LENGTH_TAG(alg) == PSA_ALG_CCM || \ PSA_ALG_AEAD_WITH_DEFAULT_LENGTH_TAG(alg) == PSA_ALG_GCM) ? 12 : \ (key_type) == PSA_KEY_TYPE_CHACHA20 && \ PSA_ALG_AEAD_WITH_DEFAULT_LENGTH_TAG(alg) == PSA_ALG_CHACHA20_POLY1305 ? 12 : \ 0) /** The maximum default nonce size among all supported pairs of key types and AEAD algorithms, in bytes. * * This is equal to or greater than any value that #PSA_AEAD_NONCE_LENGTH() may return. * * \note This is not the maximum size of nonce supported as input to #psa_aead_set_nonce(), * #psa_aead_encrypt() or #psa_aead_decrypt(), just the largest size that may be generated by * #psa_aead_generate_nonce(). */ #define PSA_AEAD_NONCE_MAX_SIZE 12 /** The default IV size for a cipher algorithm, in bytes. * * The IV that is generated as part of a call to #psa_cipher_encrypt() is always * the default IV length for the algorithm. * * This macro can be used to allocate a buffer of sufficient size to * store the IV output from #psa_cipher_generate_iv() when using * a multi-part cipher operation. * * See also #PSA_CIPHER_IV_MAX_SIZE. * * \warning This macro may evaluate its arguments multiple times or * zero times, so you should not pass arguments that contain * side effects. * * \param key_type A symmetric key type that is compatible with algorithm \p alg. * * \param alg A cipher algorithm (\c PSA_ALG_XXX value such that #PSA_ALG_IS_CIPHER(\p alg) is true). * * \return The default IV size for the specified key type and algorithm. * If the algorithm does not use an IV, return 0. * If the key type or cipher algorithm is not recognized, * or the parameters are incompatible, return 0. * An implementation can return either 0 or a correct size for a key type * and cipher algorithm that it recognizes, but does not support. */ #define PSA_CIPHER_IV_LENGTH(key_type, alg) \ (PSA_BLOCK_CIPHER_BLOCK_LENGTH(key_type) > 1 && \ ((alg) == PSA_ALG_CTR || \ (alg) == PSA_ALG_CFB || \ (alg) == PSA_ALG_OFB || \ (alg) == PSA_ALG_XTS || \ (alg) == PSA_ALG_CBC_NO_PADDING || \ (alg) == PSA_ALG_CBC_PKCS7) ? PSA_BLOCK_CIPHER_BLOCK_LENGTH(key_type) : \ (key_type) == PSA_KEY_TYPE_CHACHA20 && \ (alg) == PSA_ALG_STREAM_CIPHER ? 12 : \ 0) /** The maximum IV size for all supported cipher algorithms, in bytes. * * See also #PSA_CIPHER_IV_LENGTH(). */ #define PSA_CIPHER_IV_MAX_SIZE 16 #endif /* PSA_CRYPTO_SIZES_H */