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Use mbedtls_xor in ChaCha20

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Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
This commit is contained in:
Dave Rodgman 2022-11-22 16:35:42 +00:00
parent 0d3b55bca8
commit c1d9022bab
1 changed files with 2 additions and 16 deletions
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18
library/chacha20.c
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@ -222,7 +222,6 @@ int mbedtls_chacha20_update( mbedtls_chacha20_context *ctx,
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 @@ int mbedtls_chacha20_update( mbedtls_chacha20_context *ctx,
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 @@ int mbedtls_chacha20_update( mbedtls_chacha20_context *ctx,
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;