static int sms4_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
const unsigned char *iv, int enc)
{
int mode;
mode = ctx->cipher->flags & EVP_CIPH_MODE;
if ((mode == EVP_CIPH_ECB_MODE || mode == EVP_CIPH_CBC_MODE) && !enc) {
ret = sms4_set_decrypt_key(key, ctx->key_len * 8, ctx->cipher_data);
sms4->block = (block128_f)sms4_decrypt;
sms4->stream.cbc = (mode == EVP_CIPH_CBC_MODE ?
(cbc128_f)sms4_cbc_encrypt : NULL);
} else {
ret = sms4_set_encrypt_key(key, ctx->key_len * 8, ctx->cipher_data);
sms4->block = (block128_f)sms4_encrypt;
if (mode == EVP_CIPH_CBC_MODE) {
sms4->stream.cbc = (cbc128_f)sms4_cbc_encrypt;
} else if (mode == EVP_CIPH_CTR_MODE) {
sms4->stream.ctr = (ctr128_f)sms4_ctr32_encrypt_blocks;
} else {
sms4->stream.cbc = NULL;
}
}
if (ret < 0) {
return 0;
}
return 1;
}
static int sms4_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
const unsigned char *iv, int enc)
{
if(!enc) {
if (EVP_CIPHER_CTX_mode(ctx) == EVP_CIPH_OFB_MODE) enc = 1;
else if (EVP_CIPHER_CTX_mode(ctx) == EVP_CIPH_CFB_MODE) enc = 1; //encrypt key == decrypt key
}
if (enc)
sms4_set_encrypt_key(ctx->cipher_data, key);
else //ecb, cbc
sms4_set_decrypt_key(ctx->cipher_data, key);
return 1;
}
static int sms4_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
const unsigned char *iv, int enc)
{
int mode;
EVP_SMS4_KEY *dat = EVP_C_DATA(EVP_SMS4_KEY, ctx);
mode = EVP_CIPHER_CTX_mode(ctx);
if ((mode == EVP_CIPH_ECB_MODE || mode == EVP_CIPH_CBC_MODE) && !enc) {
sms4_set_decrypt_key(&dat->ks, key);
} else {
sms4_set_encrypt_key(&dat->ks, key);
}
dat->block = (block128_f)sms4_encrypt;
dat->stream.cbc = mode == EVP_CIPH_CBC_MODE ? (cbc128_f) sms4_cbc_encrypt : NULL;
return 1;
}
static int sms4_wrap_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
const unsigned char *iv, int enc)
{
EVP_SMS4_WRAP_CTX *wctx = EVP_C_DATA(EVP_SMS4_WRAP_CTX,ctx);
if (!iv && !key)
return 1;
if (key) {
if (EVP_CIPHER_CTX_encrypting(ctx))
sms4_set_encrypt_key(&wctx->ks.ks, key);
else
sms4_set_decrypt_key(&wctx->ks.ks, key);
if (!iv)
wctx->iv = NULL;
}
if (iv) {
memcpy(EVP_CIPHER_CTX_iv_noconst(ctx), iv, EVP_CIPHER_CTX_iv_length(ctx));
wctx->iv = EVP_CIPHER_CTX_iv_noconst(ctx);
}
return 1;
}
// 解密
unsigned char SMS4_Decryption(unsigned char *key,
unsigned char *ciphertext, unsigned short ciphertextlen,
unsigned char *plaintext, unsigned short *plaintextlen,
unsigned char *IV)
{
assert(key && ciphertext && plaintext && plaintextlen && IV);
sms4_key_t pkey;
sms4_set_decrypt_key(&pkey, key);
sms4_cbc_encrypt(ciphertext, ciphertext, ciphertextlen, &pkey, IV, 0);
int pad = ciphertext[ciphertextlen - 1];
for (int i = 1; i <= pad; ++ i) {
if (ciphertext[ciphertextlen - i] != pad)
return 1; // 补齐出错
}
*plaintextlen = ciphertextlen - pad;
memcpy(plaintext, ciphertext, *plaintextlen);
return 0;
}
