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add basic ecc encrypt/decrypt

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This commit is contained in:
toddouska
2013-11-07 15:59:31 -08:00
parent fb8c3e0c75
commit 554adff672
4 changed files with 402 additions and 1 deletions
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270
ctaocrypt/src/ecc.c
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@@ -33,6 +33,11 @@
#include <cyassl/ctaocrypt/asn.h>
#include <cyassl/ctaocrypt/error.h>
#ifdef HAVE_ECC_ENCRYPT
#include <cyassl/ctaocrypt/hmac.h>
#include <cyassl/ctaocrypt/aes.h>
#endif
/* map
@@ -3484,6 +3489,269 @@ void ecc_fp_free(void)
}
#endif /* FP_ECC */
#ifdef HAVE_ECC_ENCRYPT
/* init and set defaults, just holders */
void ecc_encrypt_init_options(ecEncOptions* options)
{
if (options) {
XMEMSET(options, 0, sizeof(ecEncOptions));
options->encAlgo = ecAES_128_CBC;
options->kdfAlgo = ecHKDF_SHA256;
options->macAlgo = ecHMAC_SHA256;
}
}
/* free any resources, clear any keys */
void ecc_encrypt_free_options(ecEncOptions* options)
{
if (options) {
XMEMSET(options, 0, sizeof(ecEncOptions));
}
}
static int ecc_get_key_sizes(ecEncOptions* options, int* encKeySz, int* ivSz,
int* keysLen, word32* digestSz, word32* blockSz)
{
if (options) {
switch (options->encAlgo) {
case ecAES_128_CBC:
*encKeySz = KEY_SIZE_128;
*ivSz = IV_SIZE_64;
*blockSz = AES_BLOCK_SIZE;
break;
default:
return BAD_FUNC_ARG;
}
switch (options->macAlgo) {
case ecHMAC_SHA256:
*digestSz = SHA256_DIGEST_SIZE;
break;
default:
return BAD_FUNC_ARG;
}
} else
return BAD_FUNC_ARG;
*keysLen = *encKeySz + *ivSz + *digestSz;
return 0;
}
/* ecc encrypt with shared secret run through kdf
options holds non default algos and inputs
msgSz should be the right size for encAlgo, i.e., already padded
return 0 on success */
int ecc_encrypt(ecc_key* privKey, ecc_key* pubKey, const byte* msg,
word32 msgSz, byte* out, word32* outSz, ecEncOptions* opts)
{
int ret;
word32 blockSz;
word32 digestSz;
ecEncOptions options;
byte sharedSecret[ECC_MAXSIZE]; /* 521 max size */
byte keys[ECC_BUFSIZE]; /* max size */
word32 sharedSz = sizeof(sharedSecret);
int keysLen;
int encKeySz;
int ivSz;
byte* encKey;
byte* encIv;
byte* macKey;
if (privKey == NULL || pubKey == NULL || msg == NULL || out == NULL ||
outSz == NULL)
return BAD_FUNC_ARG;
if (opts)
options = *opts;
else {
ecc_encrypt_init_options(&options); /* defaults */
}
ret = ecc_get_key_sizes(&options, &encKeySz, &ivSz, &keysLen, &digestSz,
&blockSz);
if (ret != 0)
return ret;
if ( (msgSz%blockSz) != 0)
return BAD_FUNC_ARG;
if (*outSz < (msgSz + digestSz))
return BUFFER_E;
ret = ecc_shared_secret(privKey, pubKey, sharedSecret, &sharedSz);
if (ret != 0)
return ret;
switch (options.kdfAlgo) {
case ecHKDF_SHA256 :
ret = HKDF(SHA256, sharedSecret, sharedSz, options.kdfSalt,
options.kdfSaltSz, options.kdfInfo,
options.kdfInfoSz, keys, keysLen);
if (ret != 0)
return ret;
break;
default:
return BAD_FUNC_ARG;
}
encKey = keys;
encIv = encKey + encKeySz;
macKey = encKey + encKeySz + ivSz;
switch (options.encAlgo) {
case ecAES_128_CBC:
{
Aes aes;
ret = AesSetKey(&aes, encKey,KEY_SIZE_128,encIv,AES_ENCRYPTION);
if (ret != 0)
return ret;
ret = AesCbcEncrypt(&aes, out, msg, msgSz);
if (ret != 0)
return ret;
}
break;
default:
return BAD_FUNC_ARG;
}
switch (options.macAlgo) {
case ecHMAC_SHA256:
{
Hmac hmac;
ret = HmacSetKey(&hmac, SHA256, macKey, SHA256_DIGEST_SIZE);
if (ret != 0)
return ret;
HmacUpdate(&hmac, out, msgSz);
HmacUpdate(&hmac, options.macSalt, options.macSaltSz);
HmacFinal(&hmac, out+msgSz);
}
break;
default:
return BAD_FUNC_ARG;
}
*outSz = msgSz + digestSz;
return 0;
}
int ecc_decrypt(ecc_key* privKey, ecc_key* pubKey, const byte* msg,
word32 msgSz, byte* out, word32* outSz, ecEncOptions* opts)
{
int ret;
word32 blockSz;
word32 digestSz;
ecEncOptions options;
byte sharedSecret[ECC_MAXSIZE]; /* 521 max size */
byte keys[ECC_BUFSIZE]; /* max size */
word32 sharedSz = sizeof(sharedSecret);
int keysLen;
int encKeySz;
int ivSz;
byte* encKey;
byte* encIv;
byte* macKey;
if (privKey == NULL || pubKey == NULL || msg == NULL || out == NULL ||
outSz == NULL)
return BAD_FUNC_ARG;
if (opts)
options = *opts;
else {
ecc_encrypt_init_options(&options); /* defaults */
}
ret = ecc_get_key_sizes(&options, &encKeySz, &ivSz, &keysLen, &digestSz,
&blockSz);
if (ret != 0)
return ret;
if ( ((msgSz-digestSz) % blockSz) != 0)
return BAD_FUNC_ARG;
if (*outSz < (msgSz - digestSz))
return BUFFER_E;
ret = ecc_shared_secret(privKey, pubKey, sharedSecret, &sharedSz);
if (ret != 0)
return ret;
switch (options.kdfAlgo) {
case ecHKDF_SHA256 :
ret = HKDF(SHA256, sharedSecret, sharedSz, options.kdfSalt,
options.kdfSaltSz, options.kdfInfo,
options.kdfInfoSz, keys, keysLen);
if (ret != 0)
return ret;
break;
default:
return BAD_FUNC_ARG;
}
encKey = keys;
encIv = encKey + encKeySz;
macKey = encKey + encKeySz + ivSz;
switch (options.macAlgo) {
case ecHMAC_SHA256:
{
byte verify[SHA256_DIGEST_SIZE];
Hmac hmac;
ret = HmacSetKey(&hmac, SHA256, macKey, SHA256_DIGEST_SIZE);
if (ret != 0)
return ret;
HmacUpdate(&hmac, msg, msgSz-digestSz);
HmacUpdate(&hmac, options.macSalt, options.macSaltSz);
HmacFinal(&hmac, verify);
if (memcmp(verify, msg + msgSz - digestSz, digestSz) != 0) {
return -1;
}
}
break;
default:
return BAD_FUNC_ARG;
}
switch (options.encAlgo) {
case ecAES_128_CBC:
{
Aes aes;
ret = AesSetKey(&aes, encKey,KEY_SIZE_128,encIv,AES_DECRYPTION);
if (ret != 0)
return ret;
ret = AesCbcDecrypt(&aes, out, msg, msgSz-digestSz);
if (ret != 0)
return ret;
}
break;
default:
return BAD_FUNC_ARG;
}
*outSz = msgSz - digestSz;
return 0;
}
#endif /* HAVE_ECC_ENCRYPT */
#endif /* HAVE_ECC */