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Implemented AES/Camellia counter mode in gcrypt

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This commit is contained in:
Martin Willi
2010-08-13 17:11:53 +02:00
parent 3b77c27a5b
commit 42cbe87fc7
3 changed files with 73 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/libstrongswan/plugins/gcrypt/gcrypt_crypter.c
+57 -6
View File
@@ -40,12 +40,43 @@ struct private_gcrypt_crypter_t {
* gcrypt algorithm identifier
*/
int alg;
/**
* are we using counter mode?
*/
bool ctr_mode;
/**
* counter state
*/
struct {
char nonce[4];
char iv[8];
u_int32_t counter;
} __attribute__((packed)) ctr;
};
/**
* Set the IV for en/decryption
*/
static void set_iv(private_gcrypt_crypter_t *this, chunk_t iv)
{
if (this->ctr_mode)
{
memcpy(this->ctr.iv, iv.ptr, sizeof(this->ctr.iv));
this->ctr.counter = htonl(1);
gcry_cipher_setctr(this->h, &this->ctr, sizeof(this->ctr));
}
else
{
gcry_cipher_setiv(this->h, iv.ptr, iv.len);
}
}
METHOD(crypter_t, decrypt, void,
private_gcrypt_crypter_t *this, chunk_t data, chunk_t iv, chunk_t *dst)
{
gcry_cipher_setiv(this->h, iv.ptr, iv.len);
set_iv(this, iv);
if (dst)
{
@@ -61,7 +92,7 @@ METHOD(crypter_t, decrypt, void,
METHOD(crypter_t, encrypt, void,
private_gcrypt_crypter_t *this, chunk_t data, chunk_t iv, chunk_t *dst)
{
gcry_cipher_setiv(this->h, iv.ptr, iv.len);
set_iv(this, iv);
if (dst)
{
@@ -79,6 +110,10 @@ METHOD(crypter_t, get_block_size, size_t,
{
size_t len = 0;
if (this->ctr_mode)
{ /* counter mode does not need any padding */
return 1;
}
gcry_cipher_algo_info(this->alg, GCRYCTL_GET_BLKLEN, NULL, &len);
return len;
}
@@ -88,6 +123,10 @@ METHOD(crypter_t, get_iv_size, size_t,
{
size_t len = 0;
if (this->ctr_mode)
{
return sizeof(this->ctr.iv);
}
gcry_cipher_algo_info(this->alg, GCRYCTL_GET_BLKLEN, NULL, &len);
return len;
}
@@ -98,12 +137,23 @@ METHOD(crypter_t, get_key_size, size_t,
size_t len = 0;
gcry_cipher_algo_info(this->alg, GCRYCTL_GET_KEYLEN, NULL, &len);
if (this->ctr_mode)
{
return len + sizeof(this->ctr.nonce);
}
return len;
}
METHOD(crypter_t, set_key, void,
private_gcrypt_crypter_t *this, chunk_t key)
{
if (this->ctr_mode)
{
/* last 4 bytes are the nonce */
memcpy(this->ctr.nonce, key.ptr + key.len - sizeof(this->ctr.nonce),
sizeof(this->ctr.nonce));
key.len -= sizeof(this->ctr.nonce);
}
gcry_cipher_setkey(this->h, key.ptr, key.len);
}
@@ -150,8 +200,8 @@ gcrypt_crypter_t *gcrypt_crypter_create(encryption_algorithm_t algo,
}
gcrypt_alg = GCRY_CIPHER_BLOWFISH;
break;
/* case ENCR_AES_CTR:
mode = GCRY_CIPHER_MODE_CTR; */
case ENCR_AES_CTR:
mode = GCRY_CIPHER_MODE_CTR;
/* fall */
case ENCR_AES_CBC:
switch (key_size)
@@ -169,8 +219,8 @@ gcrypt_crypter_t *gcrypt_crypter_create(encryption_algorithm_t algo,
return NULL;
}
break;
/* case ENCR_CAMELLIA_CTR:
mode = GCRY_CIPHER_MODE_CTR; */
case ENCR_CAMELLIA_CTR:
mode = GCRY_CIPHER_MODE_CTR;
/* fall */
case ENCR_CAMELLIA_CBC:
switch (key_size)
@@ -234,6 +284,7 @@ gcrypt_crypter_t *gcrypt_crypter_create(encryption_algorithm_t algo,
.destroy = _destroy,
},
.alg = gcrypt_alg,
.ctr_mode = mode == GCRY_CIPHER_MODE_CTR,
);
err = gcry_cipher_open(&this->h, gcrypt_alg, mode, 0);
src/libstrongswan/plugins/gcrypt/gcrypt_plugin.c
+6
View File
@@ -170,8 +170,14 @@ plugin_t *gcrypt_plugin_create()
(crypter_constructor_t)gcrypt_crypter_create);
lib->crypto->add_crypter(lib->crypto, ENCR_AES_CBC,
(crypter_constructor_t)gcrypt_crypter_create);
lib->crypto->add_crypter(lib->crypto, ENCR_AES_CTR,
(crypter_constructor_t)gcrypt_crypter_create);
#ifdef HAVE_GCRY_CIPHER_CAMELLIA
lib->crypto->add_crypter(lib->crypto, ENCR_CAMELLIA_CBC,
(crypter_constructor_t)gcrypt_crypter_create);
lib->crypto->add_crypter(lib->crypto, ENCR_CAMELLIA_CTR,
(crypter_constructor_t)gcrypt_crypter_create);
#endif /* HAVE_GCRY_CIPHER_CAMELLIA */
lib->crypto->add_crypter(lib->crypto, ENCR_SERPENT_CBC,
(crypter_constructor_t)gcrypt_crypter_create);
lib->crypto->add_crypter(lib->crypto, ENCR_TWOFISH_CBC,