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hwcrypto aes: Performance tweak, only write key to hardware once

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Shaves ~10% off time to compute AES-CBC
This commit is contained in:
Angus Gratton
2016-09-07 14:48:20 +10:00
committed by Wu Jian Gang
parent a32e954f67
commit d951ab2661
1 changed files with 20 additions and 19 deletions
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39
components/esp32/hwcrypto/aes.c
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@@ -114,23 +114,17 @@ int esp_aes_setkey_dec( esp_aes_context *ctx, const unsigned char *key,
} }
/* /*
* Inner AES-ECB function. Call only when protected by esp_aes_acquire_hardware(). * Helper function to copy key from esp_aes_context buffer
* to hardware key registers.
* *
* Optimisation to prevent overhead of locking each time when * Only call when protected by esp_aes_acquire_hardware().
* encrypting many blocks in sequence.
*/ */
static int esp_aes_crypt_ecb_inner( esp_aes_context *ctx, static inline int esp_aes_setkey_hardware( esp_aes_context *ctx, int mode)
int mode,
const unsigned char input[16],
unsigned char output[16] )
{ {
if ( mode == ESP_AES_ENCRYPT ) { if ( mode == ESP_AES_ENCRYPT ) {
ets_aes_setkey_enc(ctx->enc.key, ctx->enc.aesbits); ets_aes_setkey_enc(ctx->enc.key, ctx->enc.aesbits);
ets_aes_crypt(input, output);
} else { } else {
ets_aes_setkey_dec(ctx->enc.key, ctx->enc.aesbits); ets_aes_setkey_dec(ctx->enc.key, ctx->enc.aesbits);
/* TODO: previous commit esp_aes_decrypt function calls this but this is not correct! */
ets_aes_crypt(input, output);
} }
return 0; return 0;
} }
@@ -143,7 +137,8 @@ void esp_aes_encrypt( esp_aes_context *ctx,
unsigned char output[16] ) unsigned char output[16] )
{ {
esp_aes_acquire_hardware(); esp_aes_acquire_hardware();
esp_aes_crypt_ecb_inner(ctx, ESP_AES_ENCRYPT, input, output); esp_aes_setkey_hardware(ctx, ESP_AES_ENCRYPT);
ets_aes_crypt(input, output);
esp_aes_release_hardware(); esp_aes_release_hardware();
} }
@@ -156,7 +151,8 @@ void esp_aes_decrypt( esp_aes_context *ctx,
unsigned char output[16] ) unsigned char output[16] )
{ {
esp_aes_acquire_hardware(); esp_aes_acquire_hardware();
esp_aes_crypt_ecb_inner(ctx, ESP_AES_DECRYPT, input, output); esp_aes_setkey_hardware(ctx, ESP_AES_DECRYPT);
ets_aes_crypt(input, output);
esp_aes_release_hardware(); esp_aes_release_hardware();
} }
@@ -170,7 +166,8 @@ int esp_aes_crypt_ecb( esp_aes_context *ctx,
unsigned char output[16] ) unsigned char output[16] )
{ {
esp_aes_acquire_hardware(); esp_aes_acquire_hardware();
esp_aes_crypt_ecb_inner(ctx, mode, input, output); esp_aes_setkey_hardware(ctx, mode);
ets_aes_crypt(input, output);
esp_aes_release_hardware(); esp_aes_release_hardware();
return 0; return 0;
} }
@@ -194,11 +191,12 @@ int esp_aes_crypt_cbc( esp_aes_context *ctx,
} }
esp_aes_acquire_hardware(); esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, mode);
if ( mode == ESP_AES_DECRYPT ) { if ( mode == ESP_AES_DECRYPT ) {
while ( length > 0 ) { while ( length > 0 ) {
memcpy( temp, input, 16 ); memcpy( temp, input, 16 );
esp_aes_crypt_ecb_inner( ctx, mode, input, output ); ets_aes_crypt(input, output);
for ( i = 0; i < 16; i++ ) { for ( i = 0; i < 16; i++ ) {
output[i] = (unsigned char)( output[i] ^ iv[i] ); output[i] = (unsigned char)( output[i] ^ iv[i] );
@@ -216,7 +214,7 @@ int esp_aes_crypt_cbc( esp_aes_context *ctx,
output[i] = (unsigned char)( input[i] ^ iv[i] ); output[i] = (unsigned char)( input[i] ^ iv[i] );
} }
esp_aes_crypt_ecb_inner( ctx, mode, output, output ); ets_aes_crypt(output, output);
memcpy( iv, output, 16 ); memcpy( iv, output, 16 );
input += 16; input += 16;
@@ -245,11 +243,12 @@ int esp_aes_crypt_cfb128( esp_aes_context *ctx,
size_t n = *iv_off; size_t n = *iv_off;
esp_aes_acquire_hardware(); esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, mode);
if ( mode == ESP_AES_DECRYPT ) { if ( mode == ESP_AES_DECRYPT ) {
while ( length-- ) { while ( length-- ) {
if ( n == 0 ) { if ( n == 0 ) {
esp_aes_crypt_ecb_inner( ctx, ESP_AES_ENCRYPT, iv, iv ); ets_aes_crypt(iv, iv );
} }
c = *input++; c = *input++;
@@ -261,7 +260,7 @@ int esp_aes_crypt_cfb128( esp_aes_context *ctx,
} else { } else {
while ( length-- ) { while ( length-- ) {
if ( n == 0 ) { if ( n == 0 ) {
esp_aes_crypt_ecb_inner( ctx, ESP_AES_ENCRYPT, iv, iv ); ets_aes_crypt(iv, iv );
} }
iv[n] = *output++ = (unsigned char)( iv[n] ^ *input++ ); iv[n] = *output++ = (unsigned char)( iv[n] ^ *input++ );
@@ -291,10 +290,11 @@ int esp_aes_crypt_cfb8( esp_aes_context *ctx,
unsigned char ov[17]; unsigned char ov[17];
esp_aes_acquire_hardware(); esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, mode);
while ( length-- ) { while ( length-- ) {
memcpy( ov, iv, 16 ); memcpy( ov, iv, 16 );
esp_aes_crypt_ecb_inner( ctx, ESP_AES_ENCRYPT, iv, iv ); ets_aes_crypt(iv, iv);
if ( mode == ESP_AES_DECRYPT ) { if ( mode == ESP_AES_DECRYPT ) {
ov[16] = *input; ov[16] = *input;
@@ -329,10 +329,11 @@ int esp_aes_crypt_ctr( esp_aes_context *ctx,
size_t n = *nc_off; size_t n = *nc_off;
esp_aes_acquire_hardware(); esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, ESP_AES_ENCRYPT);
while ( length-- ) { while ( length-- ) {
if ( n == 0 ) { if ( n == 0 ) {
esp_aes_crypt_ecb_inner( ctx, ESP_AES_ENCRYPT, nonce_counter, stream_block ); ets_aes_crypt(nonce_counter, stream_block);
for ( i = 16; i > 0; i-- ) for ( i = 16; i > 0; i-- )
if ( ++nonce_counter[i - 1] != 0 ) { if ( ++nonce_counter[i - 1] != 0 ) {