Key agreement: macros for finite-field Diffie-Hellman, ECDH

Declare macros to represent key agreement algorithms.
This commit is contained in:
Gilles Peskine 2018-09-18 11:54:43 +02:00
parent e8f0e3dc3c
commit 93098fd996
3 changed files with 98 additions and 0 deletions

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@ -1218,6 +1218,73 @@ typedef uint32_t psa_algorithm_t;
#define PSA_ALG_KEY_AGREEMENT_GET_BASE(alg) \ #define PSA_ALG_KEY_AGREEMENT_GET_BASE(alg) \
((alg) & ~PSA_ALG_KEY_DERIVATION_MASK) ((alg) & ~PSA_ALG_KEY_DERIVATION_MASK)
#define PSA_ALG_FFDH_BASE ((psa_algorithm_t)0x22100000)
/** The Diffie-Hellman key agreement algorithm.
*
* This algorithm combines the finite-field Diffie-Hellman-Merkle key
* agreement to produce a shared secret from a private key and the peer's
* public key, with a key selection or key derivation algorithm to produce
* one or more shared keys and other shared cryptographic material.
*
* \param kdf_alg A key derivation algorithm (\c PSA_ALG_XXX value such
* that #PSA_ALG_IS_KEY_DERIVATION(\p hash_alg) is true)
* or a key selection algorithm (\c PSA_ALG_XXX value such
* that #PSA_ALG_IS_SELECTION(\p hash_alg) is true).
*
* \return The Diffie-Hellman algorithm with the specified
* selection or derivation algorithm.
*/
#define PSA_ALG_FFDH(kdf_alg) \
(PSA_ALG_FFDH_BASE | ((kdf_alg) & PSA_ALG_KEY_DERIVATION_MASK))
/** Whether the specified algorithm is a finite field Diffie-Hellman algorithm.
*
* This includes every supported key selection or key agreement algorithm
* for the output of the Diffie-Hellman calculation.
*
* \param alg An algorithm identifier (value of type #psa_algorithm_t).
*
* \return 1 if \c alg is a finite field Diffie-Hellman algorithm, 0 otherwise.
* This macro may return either 0 or 1 if \c alg is not a supported
* key agreement algorithm identifier.
*/
#define PSA_ALG_IS_FFDH(alg) \
(PSA_ALG_KEY_AGREEMENT_GET_BASE(alg) == PSA_ALG_FFDH_BASE)
#define PSA_ALG_ECDH_BASE ((psa_algorithm_t)0x22200000)
/** The elliptic curve Diffie-Hellman key agreement algorithm.
*
* This algorithm combines the elliptic curve Diffie-Hellman key
* agreement to produce a shared secret from a private key and the peer's
* public key, with a key selection or key derivation algorithm to produce
* one or more shared keys and other shared cryptographic material.
*
* \param kdf_alg A key derivation algorithm (\c PSA_ALG_XXX value such
* that #PSA_ALG_IS_KEY_DERIVATION(\p hash_alg) is true)
* or a selection algorithm (\c PSA_ALG_XXX value such
* that #PSA_ALG_IS_KEY_SELECTION(\p hash_alg) is true).
*
* \return The Diffie-Hellman algorithm with the specified
* selection or derivation algorithm.
*/
#define PSA_ALG_ECDH(kdf_alg) \
(PSA_ALG_ECDH_BASE | ((kdf_alg) & PSA_ALG_KEY_DERIVATION_MASK))
/** Whether the specified algorithm is an elliptic curve Diffie-Hellman
* algorithm.
*
* This includes every supported key selection or key agreement algorithm
* for the output of the Diffie-Hellman calculation.
*
* \param alg An algorithm identifier (value of type #psa_algorithm_t).
*
* \return 1 if \c alg is an elliptic curve Diffie-Hellman algorithm,
* 0 otherwise.
* This macro may return either 0 or 1 if \c alg is not a supported
* key agreement algorithm identifier.
*/
#define PSA_ALG_IS_ECDH(alg) \
(PSA_ALG_KEY_AGREEMENT_GET_BASE(alg) == PSA_ALG_ECDH_BASE)
/**@}*/ /**@}*/
/** \defgroup key_management Key management /** \defgroup key_management Key management

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@ -244,6 +244,23 @@ key_derivation_algorithm:PSA_ALG_HKDF( PSA_ALG_SHA_256 ):ALG_IS_HKDF
Key selection: raw Key selection: raw
key_selection_algorithm:PSA_ALG_SELECT_RAW:0 key_selection_algorithm:PSA_ALG_SELECT_RAW:0
Key agreement: FFDH, raw output
depends_on:MBEDTLS_DHM_C
key_agreement_algorithm:PSA_ALG_FFDH( PSA_ALG_SELECT_RAW ):ALG_IS_FFDH:PSA_ALG_SELECT_RAW
Key agreement: FFDH, HKDF using SHA-256
depends_on:MBEDTLS_DHM_C
key_agreement_algorithm:PSA_ALG_FFDH( PSA_ALG_HKDF( PSA_ALG_SHA_256 ) ):ALG_IS_FFDH:PSA_ALG_HKDF( PSA_ALG_SHA_256 )
Key agreement: ECDH, raw output
depends_on:MBEDTLS_ECDH_C
key_agreement_algorithm:PSA_ALG_ECDH( PSA_ALG_SELECT_RAW ):ALG_IS_ECDH:PSA_ALG_SELECT_RAW
Key agreement: ECDH, HKDF using SHA-256
depends_on:MBEDTLS_ECDH_C
key_agreement_algorithm:PSA_ALG_ECDH( PSA_ALG_HKDF( PSA_ALG_SHA_256 ) ):ALG_IS_ECDH:PSA_ALG_HKDF( PSA_ALG_SHA_256 )
Key type: raw data Key type: raw data
key_type:PSA_KEY_TYPE_RAW_DATA:KEY_TYPE_IS_UNSTRUCTURED key_type:PSA_KEY_TYPE_RAW_DATA:KEY_TYPE_IS_UNSTRUCTURED

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@ -31,6 +31,8 @@
#define ALG_IS_RANDOMIZED_ECDSA ( 1u << 13 ) #define ALG_IS_RANDOMIZED_ECDSA ( 1u << 13 )
#define ALG_IS_RSA_OAEP ( 1u << 14 ) #define ALG_IS_RSA_OAEP ( 1u << 14 )
#define ALG_IS_HKDF ( 1u << 15 ) #define ALG_IS_HKDF ( 1u << 15 )
#define ALG_IS_FFDH ( 1u << 16 )
#define ALG_IS_ECDH ( 1u << 17 )
/* Flags for key type classification macros. There is a flag for every /* Flags for key type classification macros. There is a flag for every
* key type classification macro PSA_KEY_TYPE_IS_xxx except for some that * key type classification macro PSA_KEY_TYPE_IS_xxx except for some that
@ -357,6 +359,12 @@ void key_derivation_algorithm( int alg_arg, int classification_flags )
TEST_ASSERT( PSA_ALG_IS_KEY_DERIVATION( alg ) ); TEST_ASSERT( PSA_ALG_IS_KEY_DERIVATION( alg ) );
TEST_ASSERT( ! PSA_ALG_IS_KEY_SELECTION( alg ) ); TEST_ASSERT( ! PSA_ALG_IS_KEY_SELECTION( alg ) );
algorithm_classification( alg, classification_flags ); algorithm_classification( alg, classification_flags );
/* Check combinations with key agreements */
TEST_ASSERT( PSA_ALG_IS_KEY_AGREEMENT( PSA_ALG_FFDH( alg ) ) );
TEST_ASSERT( PSA_ALG_IS_KEY_AGREEMENT( PSA_ALG_ECDH( alg ) ) );
TEST_ASSERT( PSA_ALG_KEY_AGREEMENT_GET_KDF( PSA_ALG_ECDH( alg ) ) == alg );
TEST_ASSERT( PSA_ALG_KEY_AGREEMENT_GET_KDF( PSA_ALG_FFDH( alg ) ) == alg );
} }
/* END_CASE */ /* END_CASE */
@ -376,6 +384,12 @@ void key_selection_algorithm( int alg_arg, int classification_flags )
TEST_ASSERT( ! PSA_ALG_IS_KEY_DERIVATION( alg ) ); TEST_ASSERT( ! PSA_ALG_IS_KEY_DERIVATION( alg ) );
TEST_ASSERT( PSA_ALG_IS_KEY_SELECTION( alg ) ); TEST_ASSERT( PSA_ALG_IS_KEY_SELECTION( alg ) );
algorithm_classification( alg, classification_flags ); algorithm_classification( alg, classification_flags );
/* Check combinations with key agreements */
TEST_ASSERT( PSA_ALG_IS_KEY_AGREEMENT( PSA_ALG_FFDH( alg ) ) );
TEST_ASSERT( PSA_ALG_IS_KEY_AGREEMENT( PSA_ALG_ECDH( alg ) ) );
TEST_ASSERT( PSA_ALG_KEY_AGREEMENT_GET_KDF( PSA_ALG_ECDH( alg ) ) == alg );
TEST_ASSERT( PSA_ALG_KEY_AGREEMENT_GET_KDF( PSA_ALG_FFDH( alg ) ) == alg );
} }
/* END_CASE */ /* END_CASE */