| /** |
| * PSA API key derivation demonstration |
| * |
| * This program calculates a key ladder: a chain of secret material, each |
| * derived from the previous one in a deterministic way based on a label. |
| * Two keys are identical if and only if they are derived from the same key |
| * using the same label. |
| * |
| * The initial key is called the master key. The master key is normally |
| * randomly generated, but it could itself be derived from another key. |
| * |
| * This program derives a series of keys called intermediate keys. |
| * The first intermediate key is derived from the master key using the |
| * first label passed on the command line. Each subsequent intermediate |
| * key is derived from the previous one using the next label passed |
| * on the command line. |
| * |
| * This program has four modes of operation: |
| * |
| * - "generate": generate a random master key. |
| * - "wrap": derive a wrapping key from the last intermediate key, |
| * and use that key to encrypt-and-authenticate some data. |
| * - "unwrap": derive a wrapping key from the last intermediate key, |
| * and use that key to decrypt-and-authenticate some |
| * ciphertext created by wrap mode. |
| * - "save": save the last intermediate key so that it can be reused as |
| * the master key in another run of the program. |
| * |
| * See the usage() output for the command line usage. See the file |
| * `key_ladder_demo.sh` for an example run. |
| */ |
| |
| /* |
| * 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. |
| */ |
| |
| /* First include Mbed TLS headers to get the Mbed TLS configuration and |
| * platform definitions that we'll use in this program. Also include |
| * standard C headers for functions we'll use here. */ |
| #if !defined(MBEDTLS_CONFIG_FILE) |
| #include "mbedtls/config.h" |
| #else |
| #include MBEDTLS_CONFIG_FILE |
| #endif |
| |
| #include <stdlib.h> |
| #include <stdio.h> |
| #include <string.h> |
| |
| #include "mbedtls/platform_util.h" // for mbedtls_platform_zeroize |
| |
| #include <psa/crypto.h> |
| |
| /* If the build options we need are not enabled, compile a placeholder. */ |
| #if !defined(MBEDTLS_SHA256_C) || !defined(MBEDTLS_MD_C) || \ |
| !defined(MBEDTLS_AES_C) || !defined(MBEDTLS_CCM_C) || \ |
| !defined(MBEDTLS_PSA_CRYPTO_C) || !defined(MBEDTLS_FS_IO) || \ |
| defined(MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER) |
| int main( void ) |
| { |
| printf( "MBEDTLS_SHA256_C and/or MBEDTLS_MD_C and/or " |
| "MBEDTLS_AES_C and/or MBEDTLS_CCM_C and/or " |
| "MBEDTLS_PSA_CRYPTO_C and/or MBEDTLS_FS_IO " |
| "not defined and/or MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER " |
| "defined.\n" ); |
| return( 0 ); |
| } |
| #else |
| |
| /* The real program starts here. */ |
| |
| /* Run a system function and bail out if it fails. */ |
| #define SYS_CHECK( expr ) \ |
| do \ |
| { \ |
| if( ! ( expr ) ) \ |
| { \ |
| perror( #expr ); \ |
| status = DEMO_ERROR; \ |
| goto exit; \ |
| } \ |
| } \ |
| while( 0 ) |
| |
| /* Run a PSA function and bail out if it fails. */ |
| #define PSA_CHECK( expr ) \ |
| do \ |
| { \ |
| status = ( expr ); \ |
| if( status != PSA_SUCCESS ) \ |
| { \ |
| printf( "Error %d at line %d: %s\n", \ |
| (int) status, \ |
| __LINE__, \ |
| #expr ); \ |
| goto exit; \ |
| } \ |
| } \ |
| while( 0 ) |
| |
| /* To report operational errors in this program, use an error code that is |
| * different from every PSA error code. */ |
| #define DEMO_ERROR 120 |
| |
| /* The maximum supported key ladder depth. */ |
| #define MAX_LADDER_DEPTH 10 |
| |
| /* Salt to use when deriving an intermediate key. */ |
| #define DERIVE_KEY_SALT ( (uint8_t *) "key_ladder_demo.derive" ) |
| #define DERIVE_KEY_SALT_LENGTH ( strlen( (const char*) DERIVE_KEY_SALT ) ) |
| |
| /* Salt to use when deriving a wrapping key. */ |
| #define WRAPPING_KEY_SALT ( (uint8_t *) "key_ladder_demo.wrap" ) |
| #define WRAPPING_KEY_SALT_LENGTH ( strlen( (const char*) WRAPPING_KEY_SALT ) ) |
| |
| /* Size of the key derivation keys (applies both to the master key and |
| * to intermediate keys). */ |
| #define KEY_SIZE_BYTES 40 |
| |
| /* Algorithm for key derivation. */ |
| #define KDF_ALG PSA_ALG_HKDF( PSA_ALG_SHA_256 ) |
| |
| /* Type and size of the key used to wrap data. */ |
| #define WRAPPING_KEY_TYPE PSA_KEY_TYPE_AES |
| #define WRAPPING_KEY_BITS 128 |
| |
| /* Cipher mode used to wrap data. */ |
| #define WRAPPING_ALG PSA_ALG_CCM |
| |
| /* Nonce size used to wrap data. */ |
| #define WRAPPING_IV_SIZE 13 |
| |
| /* Header used in files containing wrapped data. We'll save this header |
| * directly without worrying about data representation issues such as |
| * integer sizes and endianness, because the data is meant to be read |
| * back by the same program on the same machine. */ |
| #define WRAPPED_DATA_MAGIC "key_ladder_demo" // including trailing null byte |
| #define WRAPPED_DATA_MAGIC_LENGTH ( sizeof( WRAPPED_DATA_MAGIC ) ) |
| typedef struct |
| { |
| char magic[WRAPPED_DATA_MAGIC_LENGTH]; |
| size_t ad_size; /* Size of the additional data, which is this header. */ |
| size_t payload_size; /* Size of the encrypted data. */ |
| /* Store the IV inside the additional data. It's convenient. */ |
| uint8_t iv[WRAPPING_IV_SIZE]; |
| } wrapped_data_header_t; |
| |
| /* The modes that this program can operate in (see usage). */ |
| enum program_mode |
| { |
| MODE_GENERATE, |
| MODE_SAVE, |
| MODE_UNWRAP, |
| MODE_WRAP |
| }; |
| |
| /* Save a key to a file. In the real world, you may want to export a derived |
| * key sometimes, to share it with another party. */ |
| static psa_status_t save_key( psa_key_id_t key, |
| const char *output_file_name ) |
| { |
| psa_status_t status = PSA_SUCCESS; |
| uint8_t key_data[KEY_SIZE_BYTES]; |
| size_t key_size; |
| FILE *key_file = NULL; |
| |
| PSA_CHECK( psa_export_key( key, |
| key_data, sizeof( key_data ), |
| &key_size ) ); |
| SYS_CHECK( ( key_file = fopen( output_file_name, "wb" ) ) != NULL ); |
| SYS_CHECK( fwrite( key_data, 1, key_size, key_file ) == key_size ); |
| SYS_CHECK( fclose( key_file ) == 0 ); |
| key_file = NULL; |
| |
| exit: |
| if( key_file != NULL) |
| fclose( key_file ); |
| return( status ); |
| } |
| |
| /* Generate a master key for use in this demo. |
| * |
| * Normally a master key would be non-exportable. For the purpose of this |
| * demo, we want to save it to a file, to avoid relying on the keystore |
| * capability of the PSA crypto library. */ |
| static psa_status_t generate( const char *key_file_name ) |
| { |
| psa_status_t status = PSA_SUCCESS; |
| psa_key_id_t key = 0; |
| psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; |
| |
| psa_set_key_usage_flags( &attributes, |
| PSA_KEY_USAGE_DERIVE | PSA_KEY_USAGE_EXPORT ); |
| psa_set_key_algorithm( &attributes, KDF_ALG ); |
| psa_set_key_type( &attributes, PSA_KEY_TYPE_DERIVE ); |
| psa_set_key_bits( &attributes, PSA_BYTES_TO_BITS( KEY_SIZE_BYTES ) ); |
| |
| PSA_CHECK( psa_generate_key( &attributes, &key ) ); |
| |
| PSA_CHECK( save_key( key, key_file_name ) ); |
| |
| exit: |
| (void) psa_destroy_key( key ); |
| return( status ); |
| } |
| |
| /* Load the master key from a file. |
| * |
| * In the real world, this master key would be stored in an internal memory |
| * and the storage would be managed by the keystore capability of the PSA |
| * crypto library. */ |
| static psa_status_t import_key_from_file( psa_key_usage_t usage, |
| psa_algorithm_t alg, |
| const char *key_file_name, |
| psa_key_id_t *master_key ) |
| { |
| psa_status_t status = PSA_SUCCESS; |
| psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; |
| uint8_t key_data[KEY_SIZE_BYTES]; |
| size_t key_size; |
| FILE *key_file = NULL; |
| unsigned char extra_byte; |
| |
| SYS_CHECK( ( key_file = fopen( key_file_name, "rb" ) ) != NULL ); |
| SYS_CHECK( ( key_size = fread( key_data, 1, sizeof( key_data ), |
| key_file ) ) != 0 ); |
| if( fread( &extra_byte, 1, 1, key_file ) != 0 ) |
| { |
| printf( "Key file too large (max: %u).\n", |
| (unsigned) sizeof( key_data ) ); |
| status = DEMO_ERROR; |
| goto exit; |
| } |
| SYS_CHECK( fclose( key_file ) == 0 ); |
| key_file = NULL; |
| |
| psa_set_key_usage_flags( &attributes, usage ); |
| psa_set_key_algorithm( &attributes, alg ); |
| psa_set_key_type( &attributes, PSA_KEY_TYPE_DERIVE ); |
| PSA_CHECK( psa_import_key( &attributes, key_data, key_size, master_key ) ); |
| exit: |
| if( key_file != NULL ) |
| fclose( key_file ); |
| mbedtls_platform_zeroize( key_data, sizeof( key_data ) ); |
| if( status != PSA_SUCCESS ) |
| { |
| /* If the key creation hasn't happened yet or has failed, |
| * *master_key is null. psa_destroy_key( 0 ) is |
| * guaranteed to do nothing and return PSA_SUCCESS. */ |
| (void) psa_destroy_key( *master_key ); |
| *master_key = 0; |
| } |
| return( status ); |
| } |
| |
| /* Derive the intermediate keys, using the list of labels provided on |
| * the command line. On input, *key is the master key identifier. |
| * This function destroys the master key. On successful output, *key |
| * is the identifier of the final derived key. |
| */ |
| static psa_status_t derive_key_ladder( const char *ladder[], |
| size_t ladder_depth, |
| psa_key_id_t *key ) |
| { |
| psa_status_t status = PSA_SUCCESS; |
| psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; |
| psa_key_derivation_operation_t operation = PSA_KEY_DERIVATION_OPERATION_INIT; |
| size_t i; |
| |
| psa_set_key_usage_flags( &attributes, |
| PSA_KEY_USAGE_DERIVE | PSA_KEY_USAGE_EXPORT ); |
| psa_set_key_algorithm( &attributes, KDF_ALG ); |
| psa_set_key_type( &attributes, PSA_KEY_TYPE_DERIVE ); |
| psa_set_key_bits( &attributes, PSA_BYTES_TO_BITS( KEY_SIZE_BYTES ) ); |
| |
| /* For each label in turn, ... */ |
| for( i = 0; i < ladder_depth; i++ ) |
| { |
| /* Start deriving material from the master key (if i=0) or from |
| * the current intermediate key (if i>0). */ |
| PSA_CHECK( psa_key_derivation_setup( &operation, KDF_ALG ) ); |
| PSA_CHECK( psa_key_derivation_input_bytes( |
| &operation, PSA_KEY_DERIVATION_INPUT_SALT, |
| DERIVE_KEY_SALT, DERIVE_KEY_SALT_LENGTH ) ); |
| PSA_CHECK( psa_key_derivation_input_key( |
| &operation, PSA_KEY_DERIVATION_INPUT_SECRET, |
| *key ) ); |
| PSA_CHECK( psa_key_derivation_input_bytes( |
| &operation, PSA_KEY_DERIVATION_INPUT_INFO, |
| (uint8_t*) ladder[i], strlen( ladder[i] ) ) ); |
| /* When the parent key is not the master key, destroy it, |
| * since it is no longer needed. */ |
| PSA_CHECK( psa_destroy_key( *key ) ); |
| *key = 0; |
| /* Derive the next intermediate key from the parent key. */ |
| PSA_CHECK( psa_key_derivation_output_key( &attributes, &operation, |
| key ) ); |
| PSA_CHECK( psa_key_derivation_abort( &operation ) ); |
| } |
| |
| exit: |
| psa_key_derivation_abort( &operation ); |
| if( status != PSA_SUCCESS ) |
| { |
| psa_destroy_key( *key ); |
| *key = 0; |
| } |
| return( status ); |
| } |
| |
| /* Derive a wrapping key from the last intermediate key. */ |
| static psa_status_t derive_wrapping_key( psa_key_usage_t usage, |
| psa_key_id_t derived_key, |
| psa_key_id_t *wrapping_key ) |
| { |
| psa_status_t status = PSA_SUCCESS; |
| psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; |
| psa_key_derivation_operation_t operation = PSA_KEY_DERIVATION_OPERATION_INIT; |
| |
| *wrapping_key = 0; |
| |
| /* Set up a key derivation operation from the key derived from |
| * the master key. */ |
| PSA_CHECK( psa_key_derivation_setup( &operation, KDF_ALG ) ); |
| PSA_CHECK( psa_key_derivation_input_bytes( |
| &operation, PSA_KEY_DERIVATION_INPUT_SALT, |
| WRAPPING_KEY_SALT, WRAPPING_KEY_SALT_LENGTH ) ); |
| PSA_CHECK( psa_key_derivation_input_key( |
| &operation, PSA_KEY_DERIVATION_INPUT_SECRET, |
| derived_key ) ); |
| PSA_CHECK( psa_key_derivation_input_bytes( |
| &operation, PSA_KEY_DERIVATION_INPUT_INFO, |
| NULL, 0 ) ); |
| |
| /* Create the wrapping key. */ |
| psa_set_key_usage_flags( &attributes, usage ); |
| psa_set_key_algorithm( &attributes, WRAPPING_ALG ); |
| psa_set_key_type( &attributes, PSA_KEY_TYPE_AES ); |
| psa_set_key_bits( &attributes, WRAPPING_KEY_BITS ); |
| PSA_CHECK( psa_key_derivation_output_key( &attributes, &operation, |
| wrapping_key ) ); |
| |
| exit: |
| psa_key_derivation_abort( &operation ); |
| return( status ); |
| } |
| |
| static psa_status_t wrap_data( const char *input_file_name, |
| const char *output_file_name, |
| psa_key_id_t wrapping_key ) |
| { |
| psa_status_t status; |
| FILE *input_file = NULL; |
| FILE *output_file = NULL; |
| psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; |
| psa_key_type_t key_type; |
| long input_position; |
| size_t input_size; |
| size_t buffer_size = 0; |
| unsigned char *buffer = NULL; |
| size_t ciphertext_size; |
| wrapped_data_header_t header; |
| |
| /* Find the size of the data to wrap. */ |
| SYS_CHECK( ( input_file = fopen( input_file_name, "rb" ) ) != NULL ); |
| SYS_CHECK( fseek( input_file, 0, SEEK_END ) == 0 ); |
| SYS_CHECK( ( input_position = ftell( input_file ) ) != -1 ); |
| #if LONG_MAX > SIZE_MAX |
| if( input_position > SIZE_MAX ) |
| { |
| printf( "Input file too large.\n" ); |
| status = DEMO_ERROR; |
| goto exit; |
| } |
| #endif |
| input_size = input_position; |
| PSA_CHECK( psa_get_key_attributes( wrapping_key, &attributes ) ); |
| key_type = psa_get_key_type( &attributes ); |
| buffer_size = |
| PSA_AEAD_ENCRYPT_OUTPUT_SIZE( key_type, WRAPPING_ALG, input_size ); |
| /* Check for integer overflow. */ |
| if( buffer_size < input_size ) |
| { |
| printf( "Input file too large.\n" ); |
| status = DEMO_ERROR; |
| goto exit; |
| } |
| |
| /* Load the data to wrap. */ |
| SYS_CHECK( fseek( input_file, 0, SEEK_SET ) == 0 ); |
| SYS_CHECK( ( buffer = calloc( 1, buffer_size ) ) != NULL ); |
| SYS_CHECK( fread( buffer, 1, input_size, input_file ) == input_size ); |
| SYS_CHECK( fclose( input_file ) == 0 ); |
| input_file = NULL; |
| |
| /* Construct a header. */ |
| memcpy( &header.magic, WRAPPED_DATA_MAGIC, WRAPPED_DATA_MAGIC_LENGTH ); |
| header.ad_size = sizeof( header ); |
| header.payload_size = input_size; |
| |
| /* Wrap the data. */ |
| PSA_CHECK( psa_generate_random( header.iv, WRAPPING_IV_SIZE ) ); |
| PSA_CHECK( psa_aead_encrypt( wrapping_key, WRAPPING_ALG, |
| header.iv, WRAPPING_IV_SIZE, |
| (uint8_t *) &header, sizeof( header ), |
| buffer, input_size, |
| buffer, buffer_size, |
| &ciphertext_size ) ); |
| |
| /* Write the output. */ |
| SYS_CHECK( ( output_file = fopen( output_file_name, "wb" ) ) != NULL ); |
| SYS_CHECK( fwrite( &header, 1, sizeof( header ), |
| output_file ) == sizeof( header ) ); |
| SYS_CHECK( fwrite( buffer, 1, ciphertext_size, |
| output_file ) == ciphertext_size ); |
| SYS_CHECK( fclose( output_file ) == 0 ); |
| output_file = NULL; |
| |
| exit: |
| if( input_file != NULL ) |
| fclose( input_file ); |
| if( output_file != NULL ) |
| fclose( output_file ); |
| if( buffer != NULL ) |
| mbedtls_platform_zeroize( buffer, buffer_size ); |
| free( buffer ); |
| return( status ); |
| } |
| |
| static psa_status_t unwrap_data( const char *input_file_name, |
| const char *output_file_name, |
| psa_key_id_t wrapping_key ) |
| { |
| psa_status_t status; |
| FILE *input_file = NULL; |
| FILE *output_file = NULL; |
| psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; |
| psa_key_type_t key_type; |
| unsigned char *buffer = NULL; |
| size_t ciphertext_size = 0; |
| size_t plaintext_size; |
| wrapped_data_header_t header; |
| unsigned char extra_byte; |
| |
| /* Load and validate the header. */ |
| SYS_CHECK( ( input_file = fopen( input_file_name, "rb" ) ) != NULL ); |
| SYS_CHECK( fread( &header, 1, sizeof( header ), |
| input_file ) == sizeof( header ) ); |
| if( memcmp( &header.magic, WRAPPED_DATA_MAGIC, |
| WRAPPED_DATA_MAGIC_LENGTH ) != 0 ) |
| { |
| printf( "The input does not start with a valid magic header.\n" ); |
| status = DEMO_ERROR; |
| goto exit; |
| } |
| if( header.ad_size != sizeof( header ) ) |
| { |
| printf( "The header size is not correct.\n" ); |
| status = DEMO_ERROR; |
| goto exit; |
| } |
| PSA_CHECK( psa_get_key_attributes( wrapping_key, &attributes) ); |
| key_type = psa_get_key_type( &attributes); |
| ciphertext_size = |
| PSA_AEAD_ENCRYPT_OUTPUT_SIZE( key_type, WRAPPING_ALG, header.payload_size ); |
| /* Check for integer overflow. */ |
| if( ciphertext_size < header.payload_size ) |
| { |
| printf( "Input file too large.\n" ); |
| status = DEMO_ERROR; |
| goto exit; |
| } |
| |
| /* Load the payload data. */ |
| SYS_CHECK( ( buffer = calloc( 1, ciphertext_size ) ) != NULL ); |
| SYS_CHECK( fread( buffer, 1, ciphertext_size, |
| input_file ) == ciphertext_size ); |
| if( fread( &extra_byte, 1, 1, input_file ) != 0 ) |
| { |
| printf( "Extra garbage after ciphertext\n" ); |
| status = DEMO_ERROR; |
| goto exit; |
| } |
| SYS_CHECK( fclose( input_file ) == 0 ); |
| input_file = NULL; |
| |
| /* Unwrap the data. */ |
| PSA_CHECK( psa_aead_decrypt( wrapping_key, WRAPPING_ALG, |
| header.iv, WRAPPING_IV_SIZE, |
| (uint8_t *) &header, sizeof( header ), |
| buffer, ciphertext_size, |
| buffer, ciphertext_size, |
| &plaintext_size ) ); |
| if( plaintext_size != header.payload_size ) |
| { |
| printf( "Incorrect payload size in the header.\n" ); |
| status = DEMO_ERROR; |
| goto exit; |
| } |
| |
| /* Write the output. */ |
| SYS_CHECK( ( output_file = fopen( output_file_name, "wb" ) ) != NULL ); |
| SYS_CHECK( fwrite( buffer, 1, plaintext_size, |
| output_file ) == plaintext_size ); |
| SYS_CHECK( fclose( output_file ) == 0 ); |
| output_file = NULL; |
| |
| exit: |
| if( input_file != NULL ) |
| fclose( input_file ); |
| if( output_file != NULL ) |
| fclose( output_file ); |
| if( buffer != NULL ) |
| mbedtls_platform_zeroize( buffer, ciphertext_size ); |
| free( buffer ); |
| return( status ); |
| } |
| |
| static psa_status_t run( enum program_mode mode, |
| const char *key_file_name, |
| const char *ladder[], size_t ladder_depth, |
| const char *input_file_name, |
| const char *output_file_name ) |
| { |
| psa_status_t status = PSA_SUCCESS; |
| psa_key_id_t derivation_key = 0; |
| psa_key_id_t wrapping_key = 0; |
| |
| /* Initialize the PSA crypto library. */ |
| PSA_CHECK( psa_crypto_init( ) ); |
| |
| /* Generate mode is unlike the others. Generate the master key and exit. */ |
| if( mode == MODE_GENERATE ) |
| return( generate( key_file_name ) ); |
| |
| /* Read the master key. */ |
| PSA_CHECK( import_key_from_file( PSA_KEY_USAGE_DERIVE | PSA_KEY_USAGE_EXPORT, |
| KDF_ALG, |
| key_file_name, |
| &derivation_key ) ); |
| |
| /* Calculate the derived key for this session. */ |
| PSA_CHECK( derive_key_ladder( ladder, ladder_depth, |
| &derivation_key ) ); |
| |
| switch( mode ) |
| { |
| case MODE_SAVE: |
| PSA_CHECK( save_key( derivation_key, output_file_name ) ); |
| break; |
| case MODE_UNWRAP: |
| PSA_CHECK( derive_wrapping_key( PSA_KEY_USAGE_DECRYPT, |
| derivation_key, |
| &wrapping_key ) ); |
| PSA_CHECK( unwrap_data( input_file_name, output_file_name, |
| wrapping_key ) ); |
| break; |
| case MODE_WRAP: |
| PSA_CHECK( derive_wrapping_key( PSA_KEY_USAGE_ENCRYPT, |
| derivation_key, |
| &wrapping_key ) ); |
| PSA_CHECK( wrap_data( input_file_name, output_file_name, |
| wrapping_key ) ); |
| break; |
| default: |
| /* Unreachable but some compilers don't realize it. */ |
| break; |
| } |
| |
| exit: |
| /* Destroy any remaining key. Deinitializing the crypto library would do |
| * this anyway since they are volatile keys, but explicitly destroying |
| * keys makes the code easier to reuse. */ |
| (void) psa_destroy_key( derivation_key ); |
| (void) psa_destroy_key( wrapping_key ); |
| /* Deinitialize the PSA crypto library. */ |
| mbedtls_psa_crypto_free( ); |
| return( status ); |
| } |
| |
| static void usage( void ) |
| { |
| printf( "Usage: key_ladder_demo MODE [OPTION=VALUE]...\n" ); |
| printf( "Demonstrate the usage of a key derivation ladder.\n" ); |
| printf( "\n" ); |
| printf( "Modes:\n" ); |
| printf( " generate Generate the master key\n" ); |
| printf( " save Save the derived key\n" ); |
| printf( " unwrap Unwrap (decrypt) input with the derived key\n" ); |
| printf( " wrap Wrap (encrypt) input with the derived key\n" ); |
| printf( "\n" ); |
| printf( "Options:\n" ); |
| printf( " input=FILENAME Input file (required for wrap/unwrap)\n" ); |
| printf( " master=FILENAME File containing the master key (default: master.key)\n" ); |
| printf( " output=FILENAME Output file (required for save/wrap/unwrap)\n" ); |
| printf( " label=TEXT Label for the key derivation.\n" ); |
| printf( " This may be repeated multiple times.\n" ); |
| printf( " To get the same key, you must use the same master key\n" ); |
| printf( " and the same sequence of labels.\n" ); |
| } |
| |
| int main( int argc, char *argv[] ) |
| { |
| const char *key_file_name = "master.key"; |
| const char *input_file_name = NULL; |
| const char *output_file_name = NULL; |
| const char *ladder[MAX_LADDER_DEPTH]; |
| size_t ladder_depth = 0; |
| int i; |
| enum program_mode mode; |
| psa_status_t status; |
| |
| if( argc <= 1 || |
| strcmp( argv[1], "help" ) == 0 || |
| strcmp( argv[1], "-help" ) == 0 || |
| strcmp( argv[1], "--help" ) == 0 ) |
| { |
| usage( ); |
| return( EXIT_SUCCESS ); |
| } |
| |
| for( i = 2; i < argc; i++ ) |
| { |
| char *q = strchr( argv[i], '=' ); |
| if( q == NULL ) |
| { |
| printf( "Missing argument to option %s\n", argv[i] ); |
| goto usage_failure; |
| } |
| *q = 0; |
| ++q; |
| if( strcmp( argv[i], "input" ) == 0 ) |
| input_file_name = q; |
| else if( strcmp( argv[i], "label" ) == 0 ) |
| { |
| if( ladder_depth == MAX_LADDER_DEPTH ) |
| { |
| printf( "Maximum ladder depth %u exceeded.\n", |
| (unsigned) MAX_LADDER_DEPTH ); |
| return( EXIT_FAILURE ); |
| } |
| ladder[ladder_depth] = q; |
| ++ladder_depth; |
| } |
| else if( strcmp( argv[i], "master" ) == 0 ) |
| key_file_name = q; |
| else if( strcmp( argv[i], "output" ) == 0 ) |
| output_file_name = q; |
| else |
| { |
| printf( "Unknown option: %s\n", argv[i] ); |
| goto usage_failure; |
| } |
| } |
| |
| if( strcmp( argv[1], "generate" ) == 0 ) |
| mode = MODE_GENERATE; |
| else if( strcmp( argv[1], "save" ) == 0 ) |
| mode = MODE_SAVE; |
| else if( strcmp( argv[1], "unwrap" ) == 0 ) |
| mode = MODE_UNWRAP; |
| else if( strcmp( argv[1], "wrap" ) == 0 ) |
| mode = MODE_WRAP; |
| else |
| { |
| printf( "Unknown action: %s\n", argv[1] ); |
| goto usage_failure; |
| } |
| |
| if( input_file_name == NULL && |
| ( mode == MODE_WRAP || mode == MODE_UNWRAP ) ) |
| { |
| printf( "Required argument missing: input\n" ); |
| return( DEMO_ERROR ); |
| } |
| if( output_file_name == NULL && |
| ( mode == MODE_SAVE || mode == MODE_WRAP || mode == MODE_UNWRAP ) ) |
| { |
| printf( "Required argument missing: output\n" ); |
| return( DEMO_ERROR ); |
| } |
| |
| status = run( mode, key_file_name, |
| ladder, ladder_depth, |
| input_file_name, output_file_name ); |
| return( status == PSA_SUCCESS ? |
| EXIT_SUCCESS : |
| EXIT_FAILURE ); |
| |
| usage_failure: |
| usage( ); |
| return( EXIT_FAILURE ); |
| } |
| #endif /* MBEDTLS_SHA256_C && MBEDTLS_MD_C && MBEDTLS_AES_C && MBEDTLS_CCM_C && MBEDTLS_PSA_CRYPTO_C && MBEDTLS_FS_IO */ |
