Files
GmSSL/crypto/ecies/ecies_lib.c
2015-10-05 15:34:54 +08:00

338 lines
7.6 KiB
C

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/aes.h>
#include <openssl/hmac.h>
#include <openssl/rand.h>
#include <openssl/ecdh.h>
#include "ecies.h"
#include "kdf.h"
ECIES_CIPHERTEXT_VALUE *ECIES_do_encrypt(const ECIES_PARAMS *param,
const unsigned char *in, size_t inlen, const EC_KEY *pub_key)
{
int e = 1;
ECIES_CIPHERTEXT_VALUE *cv = NULL;
EC_KEY *ephem_key = NULL;
unsigned char *share = NULL;
unsigned char *enckey, *mackey, *p;
int sharelen, enckeylen, mackeylen, maclen, len;
EVP_CIPHER_CTX cipher_ctx;
EVP_CIPHER_CTX_init(&cipher_ctx);
if (!(cv = ECIES_CIPHERTEXT_VALUE_new()))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ERR_R_MALLOC_FAILURE);
goto err;
}
/*
* generate and encode ephem_point
*/
if (!(ephem_key = EC_KEY_new()))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_KEY_set_group(ephem_key, EC_KEY_get0_group(pub_key)))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ERR_R_EC_LIB);
goto err;
}
if (!EC_KEY_generate_key(ephem_key))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ERR_R_EC_LIB);
goto err;
}
len = (int)EC_POINT_point2oct(EC_KEY_get0_group(ephem_key),
EC_KEY_get0_public_key(ephem_key), POINT_CONVERSION_COMPRESSED,
NULL, 0, NULL);
if (!M_ASN1_OCTET_STRING_set(cv->ephem_point, NULL, len))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ERR_R_ASN1_LIB);
goto err;
}
if (EC_POINT_point2oct(EC_KEY_get0_group(ephem_key),
EC_KEY_get0_public_key(ephem_key), POINT_CONVERSION_COMPRESSED,
cv->ephem_point->data, len, NULL) <= 0)
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ERR_R_EC_LIB);
goto err;
}
/*
* use ecdh to compute enckey and mackey
*/
if (param->sym_cipher)
enckeylen = EVP_CIPHER_key_length(param->sym_cipher);
else enckeylen = inlen;
switch (param->mac_nid) {
case NID_hmac_full_ecies:
maclen = EVP_MD_size(param->mac_md);
mackeylen = EVP_MD_size(param->mac_md);
break;
case NID_hmac_half_ecies:
maclen = EVP_MD_size(param->mac_md)/2;
mackeylen = EVP_MD_size(param->mac_md);
break;
case NID_cmac_aes128_ecies:
maclen = AES_BLOCK_SIZE;
mackeylen = 128/8;
break;
case NID_cmac_aes192_ecies:
maclen = AES_BLOCK_SIZE;
mackeylen = 192/8;
break;
default:
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ERR_R_EC_LIB);
goto err;
}
sharelen = enckeylen + mackeylen;
if (!(share = OPENSSL_malloc(sharelen)))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!ECDH_compute_key(share, sharelen,
EC_KEY_get0_public_key(pub_key), ephem_key,
KDF_get_x9_63(param->kdf_md)))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ECIES_R_ECDH_FAILED);
goto err;
}
enckey = share;
mackey = share + enckeylen;
/*
* encrypt data and encode result to ciphertext
*/
if (param->sym_cipher)
len = (int)(inlen + EVP_MAX_BLOCK_LENGTH * 2);
else len = inlen;
if (!M_ASN1_OCTET_STRING_set(cv->ciphertext, NULL, len))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ERR_R_MALLOC_FAILURE);
goto err;
}
if (param->sym_cipher)
{
unsigned char iv[EVP_MAX_IV_LENGTH];
memset(iv, 0, sizeof(iv));
if (!EVP_EncryptInit(&cipher_ctx, param->sym_cipher, enckey, iv))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT,
ECIES_R_ENCRYPT_FAILED);
goto err;
}
p = cv->ciphertext->data;
if (!EVP_EncryptUpdate(&cipher_ctx, p, &len, in, (int)inlen))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT,
ECIES_R_ENCRYPT_FAILED);
goto err;
}
p += len;
if (!EVP_EncryptFinal(&cipher_ctx, p, &len))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT,
ECIES_R_ENCRYPT_FAILED);
goto err;
}
p += len;
cv->ciphertext->length = (int)(p - cv->ciphertext->data);
}
else
{
int i;
for (i = 0; i < len; i++)
cv->ciphertext->data[i] = in[i] ^ enckey[i];
cv->ciphertext->length = len;
}
/*
* calculate mactag of ciphertext and encode
*/
cv->mactag->length = maclen;
if (!M_ASN1_OCTET_STRING_set(cv->mactag, NULL, cv->mactag->length))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!HMAC(param->mac_md, mackey, mackeylen,
cv->ciphertext->data, (size_t)cv->ciphertext->length,
cv->mactag->data, (unsigned int *)&len))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ECIES_R_GEN_MAC_FAILED);
goto err;
}
e = 0;
err:
EVP_CIPHER_CTX_cleanup(&cipher_ctx);
if (share) OPENSSL_free(share);
if (ephem_key) EC_KEY_free(ephem_key);
if (e && cv)
{
ECIES_CIPHERTEXT_VALUE_free(cv);
cv = NULL;
}
return cv;
}
int ECIES_do_decrypt(const ECIES_CIPHERTEXT_VALUE *cv,
const ECIES_PARAMS *param, unsigned char *out, size_t *outlen,
EC_KEY *pri_key)
{
int r = 0;
EC_POINT *ephem_point = NULL;
unsigned char *share = NULL;
unsigned char mac[EVP_MAX_MD_SIZE];
unsigned char *enckey, *mackey;
int sharelen, enckeylen, mackeylen, len;
unsigned char *p;
EVP_CIPHER_CTX ctx;
EVP_CIPHER_CTX_init(&ctx);
// check output buffer size
if (!out)
{
*outlen = cv->ciphertext->length;
r = 1;
goto err;
}
if ((int)(*outlen) < cv->ciphertext->length)
{
*outlen = cv->ciphertext->length;
ECIESerr(ECIES_F_ECIES_DO_DECRYPT, ECIES_R_BUFFER_TOO_SMALL);
goto err;
}
/*
* decode ephem_point
*/
if (!cv->ephem_point || !cv->ephem_point->data)
{
ECIESerr(ECIES_F_ECIES_DO_DECRYPT, ECIES_R_BAD_DATA);
goto err;
}
if (!(ephem_point = EC_POINT_new(EC_KEY_get0_group(pri_key))))
{
ECIESerr(ECIES_F_ECIES_DO_ENCRYPT, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_POINT_oct2point(EC_KEY_get0_group(pri_key), ephem_point,
cv->ephem_point->data, cv->ephem_point->length, NULL))
{
ECIESerr(ECIES_F_ECIES_DO_DECRYPT, ECIES_R_BAD_DATA);
goto err;
}
/*
* use ecdh to compute enckey and mackey
*/
if (param->sym_cipher)
enckeylen = EVP_CIPHER_key_length(param->sym_cipher);
else enckeylen = cv->ciphertext->length;
mackeylen = EVP_MD_size(param->mac_md);
sharelen = enckeylen + mackeylen;
if (!(share = OPENSSL_malloc(sharelen)))
{
ECIESerr(ECIES_F_ECIES_DO_DECRYPT, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!ECDH_compute_key(share, enckeylen + mackeylen,
ephem_point, pri_key,
KDF_get_x9_63(param->kdf_md)))
{
ECIESerr(ECIES_F_ECIES_DO_DECRYPT, ECIES_R_ECDH_FAILED);
goto err;
}
enckey = share;
mackey = share + enckeylen;
/*
* generate and verify mac
*/
if (!cv->mactag || !cv->mactag->data)
{
ECIESerr(ECIES_F_ECIES_DO_DECRYPT, ECIES_R_BAD_DATA);
goto err;
}
if (!HMAC(param->mac_md, mackey, mackeylen,
cv->ciphertext->data, (size_t)cv->ciphertext->length,
mac, (unsigned int *)&len))
{
ECIESerr(ECIES_F_ECIES_DO_DECRYPT, ECIES_R_GEN_MAC_FAILED);
goto err;
}
if (len != cv->mactag->length)
{
ECIESerr(ECIES_F_ECIES_DO_DECRYPT, ECIES_R_VERIFY_MAC_FAILED);
goto err;
}
if (memcmp(cv->mactag->data, mac, len))
{
ECIESerr(ECIES_F_ECIES_DO_DECRYPT, ECIES_R_VERIFY_MAC_FAILED);
goto err;
}
/*
* decrypt ciphertext and output
*/
if (param->sym_cipher)
{
unsigned char iv[EVP_MAX_IV_LENGTH];
memset(iv, 0, sizeof(iv));
if (!EVP_DecryptInit(&ctx, param->sym_cipher, enckey, iv))
{
ECIESerr(ECIES_F_ECIES_DO_DECRYPT, ECIES_R_DECRYPT_FAILED);
goto err;
}
p = out;
if (!EVP_DecryptUpdate(&ctx, p, &len,
cv->ciphertext->data, cv->ciphertext->length))
{
ECIESerr(ECIES_F_ECIES_DO_DECRYPT, ECIES_R_DECRYPT_FAILED);
goto err;
}
p += len;
if (!EVP_DecryptFinal(&ctx, p, &len))
{
ECIESerr(ECIES_F_ECIES_DO_DECRYPT, ECIES_R_DECRYPT_FAILED);
goto err;
}
p += len;
*outlen = (int)(p - out);
}
else
{
int i;
for (i = 0; i < cv->ciphertext->length; i++)
out[i] = cv->ciphertext->data[i] ^ enckey[i];
*outlen = cv->ciphertext->length;
}
r = 1;
err:
if (share) OPENSSL_free(share);
EVP_CIPHER_CTX_cleanup(&ctx);
if (ephem_point) EC_POINT_free(ephem_point);
return r;
}