Use mbedtls_xor in ChaCha20
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/chacha20.c b/library/chacha20.c
index e53eb82..2875104 100644
--- a/library/chacha20.c
+++ b/library/chacha20.c
@@ -222,7 +222,6 @@
unsigned char *output )
{
size_t offset = 0U;
- size_t i;
/* Use leftover keystream bytes, if available */
while( size > 0U && ctx->keystream_bytes_used < CHACHA20_BLOCK_SIZE_BYTES )
@@ -242,17 +241,7 @@
chacha20_block( ctx->state, ctx->keystream8 );
ctx->state[CHACHA20_CTR_INDEX]++;
- for( i = 0U; i < 64U; i += 8U )
- {
- output[offset + i ] = input[offset + i ] ^ ctx->keystream8[i ];
- output[offset + i+1] = input[offset + i+1] ^ ctx->keystream8[i+1];
- output[offset + i+2] = input[offset + i+2] ^ ctx->keystream8[i+2];
- output[offset + i+3] = input[offset + i+3] ^ ctx->keystream8[i+3];
- output[offset + i+4] = input[offset + i+4] ^ ctx->keystream8[i+4];
- output[offset + i+5] = input[offset + i+5] ^ ctx->keystream8[i+5];
- output[offset + i+6] = input[offset + i+6] ^ ctx->keystream8[i+6];
- output[offset + i+7] = input[offset + i+7] ^ ctx->keystream8[i+7];
- }
+ mbedtls_xor( output + offset, input + offset, ctx->keystream8, 64U );
offset += CHACHA20_BLOCK_SIZE_BYTES;
size -= CHACHA20_BLOCK_SIZE_BYTES;
@@ -265,10 +254,7 @@
chacha20_block( ctx->state, ctx->keystream8 );
ctx->state[CHACHA20_CTR_INDEX]++;
- for( i = 0U; i < size; i++)
- {
- output[offset + i] = input[offset + i] ^ ctx->keystream8[i];
- }
+ mbedtls_xor( output + offset, input + offset, ctx->keystream8, size );
ctx->keystream_bytes_used = size;