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Implement SM4 GCM with CTR

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So gcm can benefits from ctr optimizations.
This commit is contained in:
Zhi Guan
2024-04-12 10:22:57 +08:00
parent 8dd2e71a54
commit 8c1c69e264
1 changed files with 7 additions and 26 deletions
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33
src/sm4_gcm.c
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@@ -27,9 +27,6 @@ int sm4_gcm_encrypt(const SM4_KEY *key, const uint8_t *iv, size_t ivlen,
const uint8_t *aad, size_t aadlen, const uint8_t *in, size_t inlen,
uint8_t *out, size_t taglen, uint8_t *tag)
{
const uint8_t *pin = in;
uint8_t *pout = out;
size_t left = inlen;
uint8_t H[16] = {0};
uint8_t Y[16];
uint8_t T[16];
@@ -51,19 +48,12 @@ int sm4_gcm_encrypt(const SM4_KEY *key, const uint8_t *iv, size_t ivlen,
sm4_encrypt(key, Y, T);
while (left) {
uint8_t block[16];
size_t len = left < 16 ? left : 16;
ctr_incr(Y);
sm4_encrypt(key, Y, block);
gmssl_memxor(pout, pin, block, len);
pin += len;
pout += len;
left -= len;
}
ctr_incr(Y);
sm4_ctr_encrypt(key, Y, in, inlen, out);
ghash(H, aad, aadlen, out, inlen, H);
gmssl_memxor(tag, T, H, taglen);
return 1;
}
@@ -71,9 +61,6 @@ int sm4_gcm_decrypt(const SM4_KEY *key, const uint8_t *iv, size_t ivlen,
const uint8_t *aad, size_t aadlen, const uint8_t *in, size_t inlen,
const uint8_t *tag, size_t taglen, uint8_t *out)
{
const uint8_t *pin = in;
uint8_t *pout = out;
size_t left = inlen;
uint8_t H[16] = {0};
uint8_t Y[16];
uint8_t T[16];
@@ -89,6 +76,7 @@ int sm4_gcm_decrypt(const SM4_KEY *key, const uint8_t *iv, size_t ivlen,
}
ghash(H, aad, aadlen, in, inlen, H);
sm4_encrypt(key, Y, T);
gmssl_memxor(T, T, H, taglen);
if (memcmp(T, tag, taglen) != 0) {
@@ -96,16 +84,9 @@ int sm4_gcm_decrypt(const SM4_KEY *key, const uint8_t *iv, size_t ivlen,
return -1;
}
while (left) {
uint8_t block[16];
size_t len = left < 16 ? left : 16;
ctr_incr(Y);
sm4_encrypt(key, Y, block);
gmssl_memxor(pout, pin, block, len);
pin += len;
pout += len;
left -= len;
}
ctr_incr(Y);
sm4_ctr_encrypt(key, Y, in, inlen, out);
return 1;
}