Add Poly1305 authenticator algorithm (RFC 7539)
Test vectors are included from RFC 7539.
Poly1305 is also added to the benchmark program.
diff --git a/library/poly1305.c b/library/poly1305.c
new file mode 100644
index 0000000..9a61a85
--- /dev/null
+++ b/library/poly1305.c
@@ -0,0 +1,518 @@
+/**
+ * \file poly1305.c
+ *
+ * \brief Poly1305 authentication algorithm.
+ *
+ * Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * This file is part of mbed TLS (https://tls.mbed.org)
+ */
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#if defined(MBEDTLS_POLY1305_C)
+
+#if !defined(MBEDTLS_POLY1305_ALT)
+
+#include "mbedtls/poly1305.h"
+
+#include <string.h>
+
+#if defined(MBEDTLS_SELF_TEST)
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdio.h>
+#define mbedtls_printf printf
+#endif /* MBEDTLS_PLATFORM_C */
+#endif /* MBEDTLS_SELF_TEST */
+
+#define POLY1305_BLOCK_SIZE_BYTES ( 16U )
+
+#define BYTES_TO_U32_LE( data, offset ) \
+ ( (uint32_t)data[offset] | \
+ (uint32_t)( (uint32_t)data[(offset) + 1] << 8 ) | \
+ (uint32_t)( (uint32_t)data[(offset) + 2] << 16 ) | \
+ (uint32_t)( (uint32_t)data[(offset) + 3] << 24 ) \
+ )
+
+/* Implementation that should never be optimized out by the compiler */
+static void mbedtls_zeroize( void *v, size_t n ) {
+ volatile unsigned char *p = v; while( n-- ) *p++ = 0;
+}
+
+/**
+ * \brief Process blocks with Poly1305.
+ *
+ * \param ctx The Poly1305 context.
+ * \param nblocks Number of blocks to process. Note that this function
+ * only processes full blocks.
+ * \param input Buffer containing the input block(s).
+ * \param needs_padding Set to 0 if the padding bit has already been applied
+ * to the input data before calling this function.
+ * Otherwise, set this parameter to 1.
+ */
+static void mbedtls_poly1305_process( mbedtls_poly1305_context *ctx,
+ size_t nblocks,
+ const unsigned char *input,
+ uint32_t needs_padding )
+{
+ uint64_t d0, d1, d2, d3;
+ uint32_t acc0, acc1, acc2, acc3, acc4;
+ uint32_t r0, r1, r2, r3;
+ uint32_t rs1, rs2, rs3;
+ size_t offset = 0U;
+ size_t i;
+
+ r0 = ctx->r[0];
+ r1 = ctx->r[1];
+ r2 = ctx->r[2];
+ r3 = ctx->r[3];
+
+ rs1 = r1 + ( r1 >> 2U );
+ rs2 = r2 + ( r2 >> 2U );
+ rs3 = r3 + ( r3 >> 2U );
+
+ acc0 = ctx->acc[0];
+ acc1 = ctx->acc[1];
+ acc2 = ctx->acc[2];
+ acc3 = ctx->acc[3];
+ acc4 = ctx->acc[4];
+
+ /* Process full blocks */
+ for ( i = 0U; i < nblocks; i++ )
+ {
+ /* Compute: acc += block */
+ /* Note that the input block is treated as a 128-bit little-endian integer */
+ d0 = (uint64_t)acc0 + BYTES_TO_U32_LE( input, offset + 0 );
+ d1 = (uint64_t)acc1 + BYTES_TO_U32_LE( input, offset + 4 ) + ( d0 >> 32U );
+ d2 = (uint64_t)acc2 + BYTES_TO_U32_LE( input, offset + 8 ) + ( d1 >> 32U );
+ d3 = (uint64_t)acc3 + BYTES_TO_U32_LE( input, offset + 12 ) + ( d2 >> 32U );
+ acc0 = (uint32_t)d0;
+ acc1 = (uint32_t)d1;
+ acc2 = (uint32_t)d2;
+ acc3 = (uint32_t)d3;
+ acc4 += (uint32_t)( d3 >> 32U ) + needs_padding;
+
+ /* Compute: acc *= r */
+ d0 = ( (uint64_t)acc0 * r0 ) +
+ ( (uint64_t)acc1 * rs3 ) +
+ ( (uint64_t)acc2 * rs2 ) +
+ ( (uint64_t)acc3 * rs1 );
+ d1 = ( (uint64_t)acc0 * r1 ) +
+ ( (uint64_t)acc1 * r0 ) +
+ ( (uint64_t)acc2 * rs3 ) +
+ ( (uint64_t)acc3 * rs2 ) +
+ ( (uint64_t)acc4 * rs1 );
+ d2 = ( (uint64_t)acc0 * r2 ) +
+ ( (uint64_t)acc1 * r1 ) +
+ ( (uint64_t)acc2 * r0 ) +
+ ( (uint64_t)acc3 * rs3 ) +
+ ( (uint64_t)acc4 * rs2 );
+ d3 = ( (uint64_t)acc0 * r3 ) +
+ ( (uint64_t)acc1 * r2 ) +
+ ( (uint64_t)acc2 * r1 ) +
+ ( (uint64_t)acc3 * r0 ) +
+ ( (uint64_t)acc4 * rs3 );
+ acc4 *= r0;
+
+ /* Compute: acc %= (2^130 - 5) (partial remainder) */
+ d1 += ( d0 >> 32 );
+ d2 += ( d1 >> 32 );
+ d3 += ( d2 >> 32 );
+ acc0 = (uint32_t)d0;
+ acc1 = (uint32_t)d1;
+ acc2 = (uint32_t)d2;
+ acc3 = (uint32_t)d3;
+ acc4 = (uint32_t)( d3 >> 32 ) + acc4;
+
+ d0 = (uint64_t)acc0 + ( acc4 >> 2 ) + ( acc4 & 0xFFFFFFFCU );
+ acc4 &= 3U;
+ acc0 = (uint32_t)d0;
+ d0 = (uint64_t)acc1 + ( d0 >> 32U );
+ acc1 = (uint32_t)d0;
+ d0 = (uint64_t)acc2 + ( d0 >> 32U );
+ acc2 = (uint32_t)d0;
+ d0 = (uint64_t)acc3 + ( d0 >> 32U );
+ acc3 = (uint32_t)d0;
+ d0 = (uint64_t)acc4 + ( d0 >> 32U );
+ acc4 = (uint32_t)d0;
+
+ offset += POLY1305_BLOCK_SIZE_BYTES;
+ }
+
+ ctx->acc[0] = acc0;
+ ctx->acc[1] = acc1;
+ ctx->acc[2] = acc2;
+ ctx->acc[3] = acc3;
+ ctx->acc[4] = acc4;
+}
+
+/**
+ * \brief Compute the Poly1305 MAC
+ *
+ * \param ctx The Poly1305 context.
+ * \param mac The buffer to where the MAC is written. Must be
+ * big enough to contain the 16-byte MAC.
+ */
+static void mbedtls_poly1305_compute_mac( const mbedtls_poly1305_context *ctx,
+ unsigned char mac[16] )
+{
+ uint64_t d;
+ uint32_t g0, g1, g2, g3, g4;
+ uint32_t acc0, acc1, acc2, acc3, acc4;
+ uint32_t mask;
+ uint32_t mask_inv;
+
+ acc0 = ctx->acc[0];
+ acc1 = ctx->acc[1];
+ acc2 = ctx->acc[2];
+ acc3 = ctx->acc[3];
+ acc4 = ctx->acc[4];
+
+ /* Before adding 's' we need to ensure that the accumulator is mod 2^130 - 5.
+ * We do this by calculating acc - (2^130 - 5), then checking if
+ * the 131st bit is set. If it is, then reduce: acc -= (2^130 - 5)
+ */
+
+ /* Calculate acc + -(2^130 - 5) */
+ d = ( (uint64_t)acc0 + 5U );
+ g0 = (uint32_t)d;
+ d = ( (uint64_t)acc1 + ( d >> 32 ) );
+ g1 = (uint32_t)d;
+ d = ( (uint64_t)acc2 + ( d >> 32 ) );
+ g2 = (uint32_t)d;
+ d = ( (uint64_t)acc3 + ( d >> 32 ) );
+ g3 = (uint32_t)d;
+ g4 = acc4 + (uint32_t)( d >> 32U );
+
+ /* mask == 0xFFFFFFFF if 131st bit is set, otherwise mask == 0 */
+ mask = (uint32_t)0U - ( g4 >> 2U );
+ mask_inv = ~mask;
+
+ /* If 131st bit is set then acc=g, otherwise, acc is unmodified */
+ acc0 = ( acc0 & mask_inv ) | ( g0 & mask );
+ acc1 = ( acc1 & mask_inv ) | ( g1 & mask );
+ acc2 = ( acc2 & mask_inv ) | ( g2 & mask );
+ acc3 = ( acc3 & mask_inv ) | ( g3 & mask );
+
+ /* Add 's' */
+ d = (uint64_t)acc0 + ctx->s[0];
+ acc0 = (uint32_t)d;
+ d = (uint64_t)acc1 + ctx->s[1] + ( d >> 32U );
+ acc1 = (uint32_t)d;
+ d = (uint64_t)acc2 + ctx->s[2] + ( d >> 32U );
+ acc2 = (uint32_t)d;
+ acc3 += ctx->s[3] + (uint32_t)( d >> 32U );
+
+ /* Compute MAC (128 least significant bits of the accumulator) */
+ mac[0] = (uint8_t)acc0;
+ mac[1] = (uint8_t)( acc0 >> 8 );
+ mac[2] = (uint8_t)( acc0 >> 16 );
+ mac[3] = (uint8_t)( acc0 >> 24 );
+ mac[4] = (uint8_t)acc1;
+ mac[5] = (uint8_t)( acc1 >> 8 );
+ mac[6] = (uint8_t)( acc1 >> 16 );
+ mac[7] = (uint8_t)( acc1 >> 24 );
+ mac[8] = (uint8_t)acc2;
+ mac[9] = (uint8_t)( acc2 >> 8 );
+ mac[10] = (uint8_t)( acc2 >> 16 );
+ mac[11] = (uint8_t)( acc2 >> 24 );
+ mac[12] = (uint8_t)acc3;
+ mac[13] = (uint8_t)( acc3 >> 8 );
+ mac[14] = (uint8_t)( acc3 >> 16 );
+ mac[15] = (uint8_t)( acc3 >> 24 );
+}
+
+void mbedtls_poly1305_init( mbedtls_poly1305_context *ctx )
+{
+ if ( ctx != NULL )
+ {
+ mbedtls_zeroize( ctx, sizeof(mbedtls_poly1305_context) );
+ }
+}
+
+void mbedtls_poly1305_free( mbedtls_poly1305_context *ctx )
+{
+ if ( ctx != NULL )
+ {
+ mbedtls_zeroize( ctx, sizeof(mbedtls_poly1305_context) );
+ }
+}
+
+int mbedtls_poly1305_setkey( mbedtls_poly1305_context *ctx,
+ const unsigned char key[32] )
+{
+ if ( ctx == NULL )
+ {
+ return( MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA );
+ }
+
+ /* r &= 0x0ffffffc0ffffffc0ffffffc0fffffff */
+ ctx->r[0] = BYTES_TO_U32_LE( key, 0 ) & 0x0FFFFFFFU;
+ ctx->r[1] = BYTES_TO_U32_LE( key, 4 ) & 0x0FFFFFFCU;
+ ctx->r[2] = BYTES_TO_U32_LE( key, 8 ) & 0x0FFFFFFCU;
+ ctx->r[3] = BYTES_TO_U32_LE( key, 12 ) & 0x0FFFFFFCU;
+
+ ctx->s[0] = BYTES_TO_U32_LE( key, 16 );
+ ctx->s[1] = BYTES_TO_U32_LE( key, 20 );
+ ctx->s[2] = BYTES_TO_U32_LE( key, 24 );
+ ctx->s[3] = BYTES_TO_U32_LE( key, 28 );
+
+ /* Initial accumulator state */
+ ctx->acc[0] = 0U;
+ ctx->acc[1] = 0U;
+ ctx->acc[2] = 0U;
+ ctx->acc[3] = 0U;
+
+ return 0;
+}
+
+int mbedtls_poly1305_update( mbedtls_poly1305_context *ctx,
+ size_t ilen,
+ const unsigned char* input )
+{
+ size_t offset = 0U;
+ size_t remaining = ilen;
+ size_t queue_free_len;
+ size_t nblocks;
+
+ if ( ( ctx == NULL ) || ( input == NULL ) )
+ {
+ return( MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA );
+ }
+
+ if ( ctx->queue_len > 0U )
+ {
+ queue_free_len = ( POLY1305_BLOCK_SIZE_BYTES - ctx->queue_len );
+
+ if ( ilen < queue_free_len )
+ {
+ /* Not enough data to complete the block.
+ * Store this data with the other leftovers.
+ */
+ memcpy( &ctx->queue[ctx->queue_len],
+ input,
+ ilen );
+
+ ctx->queue_len += ilen;
+
+ remaining = 0U;
+ }
+ else
+ {
+ /* Enough data to produce a complete block */
+ memcpy( &ctx->queue[ctx->queue_len],
+ input,
+ queue_free_len );
+
+ ctx->queue_len = 0U;
+
+ mbedtls_poly1305_process( ctx,
+ 1U,
+ ctx->queue,
+ 1U ); /* add padding bit */
+
+ offset += queue_free_len;
+ remaining -= queue_free_len;
+ }
+ }
+
+ if ( remaining >= POLY1305_BLOCK_SIZE_BYTES )
+ {
+ nblocks = remaining / POLY1305_BLOCK_SIZE_BYTES;
+
+ mbedtls_poly1305_process( ctx, nblocks, &input[offset], 1U );
+
+ offset += nblocks * POLY1305_BLOCK_SIZE_BYTES;
+ remaining %= POLY1305_BLOCK_SIZE_BYTES;
+ }
+
+ if ( remaining > 0U )
+ {
+ /* Store partial block */
+ ctx->queue_len = remaining;
+ memcpy( ctx->queue, &input[offset], remaining );
+ }
+
+ return( 0 );
+}
+
+int mbedtls_poly1305_finish( mbedtls_poly1305_context *ctx,
+ unsigned char mac[16] )
+{
+ if ( ( ctx == NULL ) || ( mac == NULL ) )
+ {
+ return( MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA );
+ }
+
+ /* Process any leftover data */
+ if ( ctx->queue_len > 0U )
+ {
+ /* Add padding bit */
+ ctx->queue[ctx->queue_len] = 1U;
+ ctx->queue_len++;
+
+ /* Pad with zeroes */
+ memset( &ctx->queue[ctx->queue_len],
+ 0,
+ POLY1305_BLOCK_SIZE_BYTES - ctx->queue_len );
+
+ mbedtls_poly1305_process( ctx,
+ 1U, /* Process 1 block */
+ ctx->queue,
+ 0U ); /* Don't add padding bit (it was just added above) */
+ }
+
+ mbedtls_poly1305_compute_mac( ctx, mac );
+
+ return( 0 );
+}
+
+#endif /* MBEDTLS_POLY1305_ALT */
+
+int mbedtls_poly1305_mac( const unsigned char key[32],
+ size_t ilen,
+ const unsigned char *input,
+ unsigned char mac[16] )
+{
+ mbedtls_poly1305_context ctx;
+ int result;
+
+ mbedtls_poly1305_init( &ctx );
+
+ result = mbedtls_poly1305_setkey( &ctx, key );
+ if ( result != 0 )
+ goto cleanup;
+
+ result = mbedtls_poly1305_update( &ctx, ilen, input );
+ if ( result != 0 )
+ goto cleanup;
+
+ result = mbedtls_poly1305_finish( &ctx, mac );
+
+cleanup:
+ mbedtls_poly1305_free( &ctx );
+ return( 0 );
+}
+
+#if defined(MBEDTLS_SELF_TEST)
+
+static const unsigned char test_keys[2][32] =
+{
+ {
+ 0x85, 0xd6, 0xbe, 0x78, 0x57, 0x55, 0x6d, 0x33,
+ 0x7f, 0x44, 0x52, 0xfe, 0x42, 0xd5, 0x06, 0xa8,
+ 0x01, 0x03, 0x80, 0x8a, 0xfb, 0x0d, 0xb2, 0xfd,
+ 0x4a, 0xbf, 0xf6, 0xaf, 0x41, 0x49, 0xf5, 0x1b
+ },
+ {
+ 0x1c, 0x92, 0x40, 0xa5, 0xeb, 0x55, 0xd3, 0x8a,
+ 0xf3, 0x33, 0x88, 0x86, 0x04, 0xf6, 0xb5, 0xf0,
+ 0x47, 0x39, 0x17, 0xc1, 0x40, 0x2b, 0x80, 0x09,
+ 0x9d, 0xca, 0x5c, 0xbc, 0x20, 0x70, 0x75, 0xc0
+ }
+};
+
+static const unsigned char test_data[2][127] =
+{
+ {
+ 0x43, 0x72, 0x79, 0x70, 0x74, 0x6f, 0x67, 0x72,
+ 0x61, 0x70, 0x68, 0x69, 0x63, 0x20, 0x46, 0x6f,
+ 0x72, 0x75, 0x6d, 0x20, 0x52, 0x65, 0x73, 0x65,
+ 0x61, 0x72, 0x63, 0x68, 0x20, 0x47, 0x72, 0x6f,
+ 0x75, 0x70
+ },
+ {
+ 0x27, 0x54, 0x77, 0x61, 0x73, 0x20, 0x62, 0x72,
+ 0x69, 0x6c, 0x6c, 0x69, 0x67, 0x2c, 0x20, 0x61,
+ 0x6e, 0x64, 0x20, 0x74, 0x68, 0x65, 0x20, 0x73,
+ 0x6c, 0x69, 0x74, 0x68, 0x79, 0x20, 0x74, 0x6f,
+ 0x76, 0x65, 0x73, 0x0a, 0x44, 0x69, 0x64, 0x20,
+ 0x67, 0x79, 0x72, 0x65, 0x20, 0x61, 0x6e, 0x64,
+ 0x20, 0x67, 0x69, 0x6d, 0x62, 0x6c, 0x65, 0x20,
+ 0x69, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x77,
+ 0x61, 0x62, 0x65, 0x3a, 0x0a, 0x41, 0x6c, 0x6c,
+ 0x20, 0x6d, 0x69, 0x6d, 0x73, 0x79, 0x20, 0x77,
+ 0x65, 0x72, 0x65, 0x20, 0x74, 0x68, 0x65, 0x20,
+ 0x62, 0x6f, 0x72, 0x6f, 0x67, 0x6f, 0x76, 0x65,
+ 0x73, 0x2c, 0x0a, 0x41, 0x6e, 0x64, 0x20, 0x74,
+ 0x68, 0x65, 0x20, 0x6d, 0x6f, 0x6d, 0x65, 0x20,
+ 0x72, 0x61, 0x74, 0x68, 0x73, 0x20, 0x6f, 0x75,
+ 0x74, 0x67, 0x72, 0x61, 0x62, 0x65, 0x2e
+ }
+};
+
+static const size_t test_data_len[2] =
+{
+ 34U,
+ 127U
+};
+
+static const unsigned char test_mac[2][16] =
+{
+ {
+ 0xa8, 0x06, 0x1d, 0xc1, 0x30, 0x51, 0x36, 0xc6,
+ 0xc2, 0x2b, 0x8b, 0xaf, 0x0c, 0x01, 0x27, 0xa9
+ },
+ {
+ 0x45, 0x41, 0x66, 0x9a, 0x7e, 0xaa, 0xee, 0x61,
+ 0xe7, 0x08, 0xdc, 0x7c, 0xbc, 0xc5, 0xeb, 0x62
+ }
+};
+
+int mbedtls_poly1305_self_test( int verbose )
+{
+ uint8_t mac[16];
+ size_t i;
+ int result;
+
+ for ( i = 0U; i < 2U; i++ )
+ {
+ result = mbedtls_poly1305_mac( test_keys[i],
+ test_data_len[i],
+ test_data[i],
+ mac );
+ if ( result != 0 )
+ {
+ if ( verbose != 0 )
+ {
+ mbedtls_printf( "Poly1305 test %zi error code: %i\n", i, result );
+ }
+
+ return( -1 );
+ }
+
+ if ( memcmp( mac, test_mac[i], 16U ) != 0 )
+ {
+ if ( verbose != 0 )
+ {
+ mbedtls_printf( "Poly1305 test %zi failed\n", i );
+ }
+
+ return( -1 );
+ }
+ }
+
+ return( 0 );
+}
+
+#endif /* MBEDTLS_SELF_TEST */
+
+#endif /* MBEDTLS_POLY1305_C */
