grasshopper_zero128(&ctx->iv_buffer);
grasshopper_zero128(&ctx->partial_buffer);
-
- ctx->counter = 0;
}
int gost_grasshopper_cipher_init(EVP_CIPHER_CTX* ctx, const unsigned char* key,
gost_grasshopper_cipher_ctx_ctr* c = EVP_CIPHER_CTX_get_cipher_data(ctx);
c->c.type = GRASSHOPPER_CIPHER_CTR;
+ EVP_CIPHER_CTX_set_num(ctx, 0);
grasshopper_zero128(&c->iv_buffer);
grasshopper_zero128(&c->partial_buffer);
- c->counter = 0;
-
return gost_grasshopper_cipher_init(ctx, key, iv, enc);
}
return 1;
}
+/* increment counter (128-bit int) by 1 */
+static void ctr128_inc(unsigned char *counter)
+{
+ unsigned int n = 16;
+ unsigned char c;
+
+ do {
+ --n;
+ c = counter[n];
+ ++c;
+ counter[n] = c;
+ if (c) return;
+ } while (n);
+}
+
int gost_grasshopper_cipher_do_ctr(EVP_CIPHER_CTX* ctx, unsigned char* out,
const unsigned char* in, size_t inl) {
gost_grasshopper_cipher_ctx_ctr* c = (gost_grasshopper_cipher_ctx_ctr*) EVP_CIPHER_CTX_get_cipher_data(ctx);
unsigned char* iv = EVP_CIPHER_CTX_iv_noconst(ctx);
const unsigned char* current_in = in;
unsigned char* current_out = out;
- size_t blocks = inl / GRASSHOPPER_BLOCK_SIZE;
grasshopper_w128_t* currentInputBlock;
grasshopper_w128_t* currentOutputBlock;
+ unsigned int n = EVP_CIPHER_CTX_num(ctx);
size_t lasted;
size_t i;
+ while (n && inl) {
+ *(current_out++) = *(current_in++) ^ c->partial_buffer.b[n];
+ --inl;
+ n = (n + 1) % GRASSHOPPER_BLOCK_SIZE;
+ }
+ EVP_CIPHER_CTX_set_num(ctx, n);
+ size_t blocks = inl / GRASSHOPPER_BLOCK_SIZE;
+
memcpy(&c->iv_buffer, iv, 8);
// full parts
for (i = 0; i < blocks; i++) {
currentInputBlock = (grasshopper_w128_t*) current_in;
currentOutputBlock = (grasshopper_w128_t*) current_out;
- memcpy(c->iv_buffer.b + 8, &c->counter, 8);
grasshopper_encrypt_block(&c->c.encrypt_round_keys, &c->iv_buffer, currentOutputBlock, &c->c.buffer);
grasshopper_append128(currentOutputBlock, currentInputBlock);
- c->counter += 1;
+ ctr128_inc(c->iv_buffer.b);
current_in += GRASSHOPPER_BLOCK_SIZE;
current_out += GRASSHOPPER_BLOCK_SIZE;
}
if (lasted > 0) {
currentInputBlock = (grasshopper_w128_t*) current_in;
currentOutputBlock = (grasshopper_w128_t*) current_out;
- memcpy(c->iv_buffer.b + 8, &c->counter, 8);
grasshopper_encrypt_block(&c->c.encrypt_round_keys, &c->iv_buffer, &c->partial_buffer, &c->c.buffer);
for (i = 0; i < lasted; i++) {
currentOutputBlock->b[i] = c->partial_buffer.b[i] ^ currentInputBlock->b[i];
}
- c->counter += 1;
+ EVP_CIPHER_CTX_set_num(ctx, i);
+ ctr128_inc(c->iv_buffer.b);
}
return 1;
int gost_grasshopper_set_asn1_parameters(EVP_CIPHER_CTX* ctx, ASN1_TYPE* params) {
int len = 0;
unsigned char* buf = NULL;
- unsigned char* p = NULL;
ASN1_OCTET_STRING* os = NULL;
os = ASN1_OCTET_STRING_new();