Commit 21f0db69 authored by Andy Polyakov's avatar Andy Polyakov
Browse files

Tune up AES CFB. Performance improvement varies from 10% to 50% from 

platform to platform. Its absolute value is within few percents
marginal from that of ECB.
parent 4d4e08ec

crypto/aes/aes.h

+1 −1
Original line number Diff line number Diff line
@@ -99,7 +99,7 @@ void AES_cbc_encrypt(const unsigned char *in, unsigned char *out, 
	const unsigned long length, const AES_KEY *key,

	unsigned char *ivec, const int enc);

void AES_cfb128_encrypt(const unsigned char *in, unsigned char *out,

	const unsigned long length, const AES_KEY *key,

	unsigned long length, const AES_KEY *key,

	unsigned char *ivec, int *num, const int enc);

void AES_cfb1_encrypt(const unsigned char *in, unsigned char *out,

	const unsigned long length, const AES_KEY *key,

crypto/aes/aes_cfb.c

+95 −12
Original line number Diff line number Diff line
@@ -116,39 +116,122 @@ 
#include "aes_locl.h"

#include "e_os.h"



#define STRICT_ALIGNMENT

#if defined(__i386) || defined(__i386__) || \

    defined(__x86_64) || defined(__x86_64__) || \

    defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64)

#  undef STRICT_ALIGNMENT

#endif



/* The input and output encrypted as though 128bit cfb mode is being

 * used.  The extra state information to record how much of the

 * 128bit block we have used is contained in *num;

 */



void AES_cfb128_encrypt(const unsigned char *in, unsigned char *out,

	const unsigned long length, const AES_KEY *key,

	unsigned long length, const AES_KEY *key,

	unsigned char *ivec, int *num, const int enc) {



    unsigned int n;

	unsigned long l = length;

	unsigned char c;

    unsigned long l = 0;



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



    n = *num;



#if !defined(OPENSSL_SMALL_FOOTPRINT)

    if (AES_BLOCK_SIZE%sizeof(size_t) == 0) {	/* always true actually */

	if (enc) {

		while (l--) {

		if (n) {

			while (length) {

				*(out++) = ivec[n] ^= *(in++);

				length--;

				if(!(n = (n + 1) % AES_BLOCK_SIZE))

					break;

			}

		}

#if defined(STRICT_ALIGNMENT)

		if (((size_t)in|(size_t)out)%sizeof(size_t) != 0)

			goto enc_unaligned;

#endif

		while ((l + AES_BLOCK_SIZE) <= length) {

			unsigned int i;

			AES_encrypt(ivec, ivec, key);

			for (i=0;i<AES_BLOCK_SIZE;i+=sizeof(size_t)) {

				*(size_t*)(out+l+i) =

				*(size_t*)(ivec+i) ^= *(size_t*)(in+l+i);

			}

			l += AES_BLOCK_SIZE;

		}



		if (l < length) {

			AES_encrypt(ivec, ivec, key);

			do {	out[l] = ivec[n] ^= in[l];

				l++; n++;

			} while (l < length);

		}

	} else {

		if (n) {

			while (length) {

				unsigned char c;

				*(out++) = ivec[n] ^ (c = *(in++)); ivec[n] = c;

				length--;

				if(!(n = (n + 1) % AES_BLOCK_SIZE))

					break;

 			}

		}

#if defined(STRICT_ALIGNMENT)

		if (((size_t)in|(size_t)out)%sizeof(size_t) != 0)

			goto dec_unaligned;

#endif

		while (l + AES_BLOCK_SIZE <= length) {

			unsigned int i;

			AES_encrypt(ivec, ivec, key);

			for (i=0;i<AES_BLOCK_SIZE;i+=sizeof(size_t)) {

				size_t t = *(size_t*)(in+l+i);

				*(size_t*)(out+l+i) = *(size_t*)(ivec+i) ^ t;

				*(size_t*)(ivec+i) = t;

			}

			l += AES_BLOCK_SIZE;

		}



		if (l < length) {

			AES_encrypt(ivec, ivec, key);

			do {	unsigned char c;

				out[l] = ivec[n] ^ (c = in[l]); ivec[n] = c;

				l++; n++;

			} while (l < length);

 		}

	}

	*num = n;

	return;

    }

#endif



    /* this code would be commonly eliminated by x86* compiler */

	if (enc) {

#if defined(STRICT_ALIGNMENT) && !defined(OPENSSL_SMALL_FOOTPRINT)

	    enc_unaligned:

#endif

		while (l<length) {

			if (n == 0) {

				AES_encrypt(ivec, ivec, key);

			}

			ivec[n] = *(out++) = *(in++) ^ ivec[n];

			out[l] = ivec[n] ^= in[l];

			l++;

			n = (n+1) % AES_BLOCK_SIZE;

		}

	} else {

		while (l--) {

#if defined(STRICT_ALIGNMENT) && !defined(OPENSSL_SMALL_FOOTPRINT)

	    dec_unaligned:

#endif

		while (l<length) {

			unsigned char c;

			if (n == 0) {

				AES_encrypt(ivec, ivec, key);

			}

			c = *(in);

			*(out++) = *(in++) ^ ivec[n];

			ivec[n] = c;

			out[l] = ivec[n] ^ (c = in[l]); ivec[n] = c;

			l++;

			n = (n+1) % AES_BLOCK_SIZE;

		}

	}