Commit 131e064e authored by Andy Polyakov's avatar Andy Polyakov
Browse files

Eliminate redundant memcpy of IV material. Performance improvement varies 

from platform to platform and can be as large as 20%.
parent 556b8f3f

crypto/aes/aes_cbc.c

+25 −7
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ void AES_cbc_encrypt(const unsigned char *in, unsigned char *out, 


	unsigned long n;

	unsigned long len = length;

	unsigned char tmp[AES_BLOCK_SIZE];

	unsigned char tmp[AES_BLOCK_SIZE], *iv = ivec;



	assert(in && out && key && ivec);

	assert((AES_ENCRYPT == enc)||(AES_DECRYPT == enc));
@@ -73,22 +73,40 @@ void AES_cbc_encrypt(const unsigned char *in, unsigned char *out, 
	if (AES_ENCRYPT == enc) {

		while (len >= AES_BLOCK_SIZE) {

			for(n=0; n < AES_BLOCK_SIZE; ++n)

				tmp[n] = in[n] ^ ivec[n];

			AES_encrypt(tmp, out, key);

			memcpy(ivec, out, AES_BLOCK_SIZE);

				out[n] = in[n] ^ iv[n];

			AES_encrypt(out, out, key);

			iv = out;

			len -= AES_BLOCK_SIZE;

			in += AES_BLOCK_SIZE;

			out += AES_BLOCK_SIZE;

		}

		if (len) {

			for(n=0; n < len; ++n)

				tmp[n] = in[n] ^ ivec[n];

				tmp[n] = in[n] ^ iv[n];

			for(n=len; n < AES_BLOCK_SIZE; ++n)

				tmp[n] = ivec[n];

				tmp[n] = iv[n];

			AES_encrypt(tmp, tmp, key);

			memcpy(out, tmp, AES_BLOCK_SIZE);

			memcpy(ivec, tmp, AES_BLOCK_SIZE);

			iv = out;

		}			

		memcpy(ivec,iv,AES_BLOCK_SIZE);

	} else if (in != out) {

		while (len >= AES_BLOCK_SIZE) {

			AES_decrypt(in, out, key);

			for(n=0; n < AES_BLOCK_SIZE; ++n)

				out[n] ^= iv[n];

			iv = in;

			len -= AES_BLOCK_SIZE;

			in  += AES_BLOCK_SIZE;

			out += AES_BLOCK_SIZE;

		}

		if (len) {

			AES_decrypt(in,tmp,key);

			for(n=0; n < len; ++n)

				out[n] = tmp[n] ^ iv[n];

			iv = in;

		}

		memcpy(ivec,iv,AES_BLOCK_SIZE);

	} else {

		while (len >= AES_BLOCK_SIZE) {

			memcpy(tmp, in, AES_BLOCK_SIZE);