diff options
Diffstat (limited to 'siv_nettle.c')
| -rw-r--r-- | siv_nettle.c | 141 |
1 files changed, 118 insertions, 23 deletions
diff --git a/siv_nettle.c b/siv_nettle.c index d8f8b23..800beb7 100644 --- a/siv_nettle.c +++ b/siv_nettle.c @@ -34,12 +34,25 @@ #include "siv_nettle_int.c" #endif +#ifdef HAVE_NETTLE_SIV_GCM +#include <nettle/siv-gcm.h> +#endif + #include "memory.h" #include "siv.h" struct SIV_Instance_Record { - struct siv_cmac_aes128_ctx siv; + SIV_Algorithm algorithm; int key_set; + int min_nonce_length; + int max_nonce_length; + int tag_length; + union { + struct siv_cmac_aes128_ctx cmac_aes128; +#ifdef HAVE_NETTLE_SIV_GCM + struct aes128_ctx aes128; +#endif + } ctx; }; /* ================================================== */ @@ -49,12 +62,30 @@ SIV_CreateInstance(SIV_Algorithm algorithm) { SIV_Instance instance; - if (algorithm != AEAD_AES_SIV_CMAC_256) + if (SIV_GetKeyLength(algorithm) <= 0) return NULL; instance = MallocNew(struct SIV_Instance_Record); + instance->algorithm = algorithm; instance->key_set = 0; + switch (algorithm) { + case AEAD_AES_SIV_CMAC_256: + instance->min_nonce_length = SIV_MIN_NONCE_SIZE; + instance->max_nonce_length = INT_MAX; + instance->tag_length = SIV_DIGEST_SIZE; + break; +#ifdef HAVE_NETTLE_SIV_GCM + case AEAD_AES_128_GCM_SIV: + instance->min_nonce_length = SIV_GCM_NONCE_SIZE; + instance->max_nonce_length = SIV_GCM_NONCE_SIZE; + instance->tag_length = SIV_GCM_DIGEST_SIZE; + break; +#endif + default: + assert(0); + } + return instance; } @@ -71,11 +102,18 @@ SIV_DestroyInstance(SIV_Instance instance) int SIV_GetKeyLength(SIV_Algorithm algorithm) { - assert(32 <= SIV_MAX_KEY_LENGTH); - - if (algorithm == AEAD_AES_SIV_CMAC_256) - return 32; - return 0; + assert(2 * AES128_KEY_SIZE <= SIV_MAX_KEY_LENGTH); + + switch (algorithm) { + case AEAD_AES_SIV_CMAC_256: + return 2 * AES128_KEY_SIZE; +#ifdef HAVE_NETTLE_SIV_GCM + case AEAD_AES_128_GCM_SIV: + return AES128_KEY_SIZE; +#endif + default: + return 0; + } } /* ================================================== */ @@ -83,10 +121,21 @@ SIV_GetKeyLength(SIV_Algorithm algorithm) int SIV_SetKey(SIV_Instance instance, const unsigned char *key, int length) { - if (length != 32) + if (length != SIV_GetKeyLength(instance->algorithm)) return 0; - siv_cmac_aes128_set_key(&instance->siv, key); + switch (instance->algorithm) { + case AEAD_AES_SIV_CMAC_256: + siv_cmac_aes128_set_key(&instance->ctx.cmac_aes128, key); + break; +#ifdef HAVE_NETTLE_SIV_GCM + case AEAD_AES_128_GCM_SIV: + aes128_set_encrypt_key(&instance->ctx.aes128, key); + break; +#endif + default: + assert(0); + } instance->key_set = 1; @@ -96,11 +145,27 @@ SIV_SetKey(SIV_Instance instance, const unsigned char *key, int length) /* ================================================== */ int -SIV_GetTagLength(SIV_Instance instance) +SIV_GetMinNonceLength(SIV_Instance instance) { - assert(SIV_DIGEST_SIZE <= SIV_MAX_TAG_LENGTH); + return instance->min_nonce_length; +} - return SIV_DIGEST_SIZE; +/* ================================================== */ + +int +SIV_GetMaxNonceLength(SIV_Instance instance) +{ + return instance->max_nonce_length; +} + +/* ================================================== */ + +int +SIV_GetTagLength(SIV_Instance instance) +{ + if (instance->tag_length < 1 || instance->tag_length > SIV_MAX_TAG_LENGTH) + assert(0); + return instance->tag_length; } /* ================================================== */ @@ -115,16 +180,31 @@ SIV_Encrypt(SIV_Instance instance, if (!instance->key_set) return 0; - if (nonce_length < SIV_MIN_NONCE_SIZE || assoc_length < 0 || + if (nonce_length < instance->min_nonce_length || + nonce_length > instance->max_nonce_length || assoc_length < 0 || plaintext_length < 0 || plaintext_length > ciphertext_length || - plaintext_length + SIV_DIGEST_SIZE != ciphertext_length) + plaintext_length + SIV_GetTagLength(instance) != ciphertext_length) return 0; assert(assoc && plaintext); - siv_cmac_aes128_encrypt_message(&instance->siv, nonce_length, nonce, - assoc_length, assoc, - ciphertext_length, ciphertext, plaintext); + switch (instance->algorithm) { + case AEAD_AES_SIV_CMAC_256: + siv_cmac_aes128_encrypt_message(&instance->ctx.cmac_aes128, + nonce_length, nonce, assoc_length, assoc, + ciphertext_length, ciphertext, plaintext); + break; +#ifdef HAVE_NETTLE_SIV_GCM + case AEAD_AES_128_GCM_SIV: + siv_gcm_aes128_encrypt_message(&instance->ctx.aes128, + nonce_length, nonce, assoc_length, assoc, + ciphertext_length, ciphertext, plaintext); + break; +#endif + default: + assert(0); + } + return 1; } @@ -140,17 +220,32 @@ SIV_Decrypt(SIV_Instance instance, if (!instance->key_set) return 0; - if (nonce_length < SIV_MIN_NONCE_SIZE || assoc_length < 0 || + if (nonce_length < instance->min_nonce_length || + nonce_length > instance->max_nonce_length || assoc_length < 0 || plaintext_length < 0 || plaintext_length > ciphertext_length || - plaintext_length + SIV_DIGEST_SIZE != ciphertext_length) + plaintext_length + SIV_GetTagLength(instance) != ciphertext_length) return 0; assert(assoc && plaintext); - if (!siv_cmac_aes128_decrypt_message(&instance->siv, nonce_length, nonce, - assoc_length, assoc, - plaintext_length, plaintext, ciphertext)) - return 0; + switch (instance->algorithm) { + case AEAD_AES_SIV_CMAC_256: + if (!siv_cmac_aes128_decrypt_message(&instance->ctx.cmac_aes128, + nonce_length, nonce, assoc_length, assoc, + plaintext_length, plaintext, ciphertext)) + return 0; + break; +#ifdef HAVE_NETTLE_SIV_GCM + case AEAD_AES_128_GCM_SIV: + if (!siv_gcm_aes128_decrypt_message(&instance->ctx.aes128, + nonce_length, nonce, assoc_length, assoc, + plaintext_length, plaintext, ciphertext)) + return 0; + break; +#endif + default: + assert(0); + } return 1; } |