Implement hashing function for ZKP
diff --git a/library/ecjpake.c b/library/ecjpake.c
index 4895990..398f4d9 100644
--- a/library/ecjpake.c
+++ b/library/ecjpake.c
@@ -21,6 +21,7 @@
/*
* EC-JPAKE is defined in Chapter 7.4 of the Thread specification.
+ * References below are base on the draft-1.0.0 spec.
*/
#if !defined(MBEDTLS_CONFIG_FILE)
@@ -33,6 +34,90 @@
#include "mbedtls/ecjpake.h"
+#include <string.h>
+
+/*
+ * Write a point plus its length to a buffer
+ */
+static int ecjpake_write_len_point( unsigned char **p,
+ const unsigned char *end,
+ const mbedtls_ecp_group *grp,
+ const mbedtls_ecp_point *P )
+{
+ int ret;
+ size_t len;
+
+ /* Need at least 4 for length plus 1 for point */
+ if( end < *p || end - *p < 5 )
+ return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
+
+ ret = mbedtls_ecp_point_write_binary( grp, P, MBEDTLS_ECP_PF_UNCOMPRESSED,
+ &len, *p + 4, end - ( *p + 4 ) );
+ if( ret != 0 )
+ return( ret );
+
+ (*p)[0] = (unsigned char)( ( len >> 24 ) & 0xFF );
+ (*p)[1] = (unsigned char)( ( len >> 16 ) & 0xFF );
+ (*p)[2] = (unsigned char)( ( len >> 8 ) & 0xFF );
+ (*p)[3] = (unsigned char)( ( len ) & 0xFF );
+
+ *p += 4 + len;
+
+ return( 0 );
+}
+
+/*
+ * Size of the temporary buffer for ecjpake_hash:
+ * 3 EC points plus their length, plus ID (6 bytes)
+ */
+#define ECJPAKE_HASH_BUF_LEN ( 3 * ( 4 + MBEDTLS_ECP_MAX_PT_LEN ) + 6 )
+
+/*
+ * Compute hash for ZKP (7.4.2.2.2.1)
+ */
+static int ecjpake_hash( const mbedtls_md_info_t *md_info,
+ const mbedtls_ecp_group *grp,
+ const mbedtls_ecp_point *G,
+ const mbedtls_ecp_point *V,
+ const mbedtls_ecp_point *X,
+ const char *id,
+ mbedtls_mpi *h )
+{
+ int ret;
+ unsigned char buf[ECJPAKE_HASH_BUF_LEN];
+ unsigned char *p = buf;
+ const unsigned char *end = buf + sizeof( buf );
+ size_t id_len = strlen( id );
+ unsigned char hash[MBEDTLS_MD_MAX_SIZE];
+
+ /* Write things to temporary buffer */
+ MBEDTLS_MPI_CHK( ecjpake_write_len_point( &p, end, grp, G ) );
+ MBEDTLS_MPI_CHK( ecjpake_write_len_point( &p, end, grp, V ) );
+ MBEDTLS_MPI_CHK( ecjpake_write_len_point( &p, end, grp, X ) );
+
+ if( end < p || (size_t)( end - p ) < id_len )
+ return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
+
+ *p++ = (unsigned char)( ( id_len >> 24 ) & 0xFF );
+ *p++ = (unsigned char)( ( id_len >> 16 ) & 0xFF );
+ *p++ = (unsigned char)( ( id_len >> 8 ) & 0xFF );
+ *p++ = (unsigned char)( ( id_len ) & 0xFF );
+
+ memcpy( p, id, id_len );
+ p += id_len;
+
+ /* Compute hash */
+ mbedtls_md( md_info, buf, p - buf, hash );
+
+ /* Turn it into an integer mod n */
+ MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( h, hash,
+ mbedtls_md_get_size( md_info ) ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( h, h, &grp->N ) );
+
+cleanup:
+ return( ret );
+}
+
#if defined(MBEDTLS_SELF_TEST)
#if defined(MBEDTLS_PLATFORM_C)
@@ -42,14 +127,106 @@
#define mbedtls_printf printf
#endif
+#if !defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) || \
+ !defined(MBEDTLS_SHA256_C)
+int mbedtls_ecjpake_self_test( int verbose )
+{
+ (void) verbose;
+ return( 0 );
+}
+#else
+
+static const unsigned char ecjpake_test_G[] = {
+ 0x04, 0x6b, 0x17, 0xd1, 0xf2, 0xe1, 0x2c, 0x42, 0x47, 0xf8, 0xbc, 0xe6,
+ 0xe5, 0x63, 0xa4, 0x40, 0xf2, 0x77, 0x03, 0x7d, 0x81, 0x2d, 0xeb, 0x33,
+ 0xa0, 0xf4, 0xa1, 0x39, 0x45, 0xd8, 0x98, 0xc2, 0x96, 0x4f, 0xe3, 0x42,
+ 0xe2, 0xfe, 0x1a, 0x7f, 0x9b, 0x8e, 0xe7, 0xeb, 0x4a, 0x7c, 0x0f, 0x9e,
+ 0x16, 0x2b, 0xce, 0x33, 0x57, 0x6b, 0x31, 0x5e, 0xce, 0xcb, 0xb6, 0x40,
+ 0x68, 0x37, 0xbf, 0x51, 0xf5
+};
+
+static const unsigned char ecjpake_test_V[] = {
+ 0x04, 0xfa, 0x9a, 0x24, 0x9d, 0x73, 0x6e, 0x30, 0x28, 0xd1, 0x2d, 0xf1,
+ 0xdc, 0xfa, 0x22, 0xd1, 0xed, 0x62, 0x82, 0xbf, 0xab, 0x27, 0x7c, 0x7c,
+ 0x52, 0x56, 0xf3, 0xfd, 0x38, 0x07, 0xa5, 0xae, 0xe0, 0x72, 0xfb, 0x4d,
+ 0x9c, 0x2b, 0xd6, 0xa4, 0x70, 0xf7, 0xb4, 0xd0, 0xbd, 0xfb, 0x4a, 0x94,
+ 0x96, 0xcf, 0xcd, 0xd3, 0x53, 0xf9, 0x90, 0x3c, 0x0a, 0x69, 0xa4, 0x4b,
+ 0x18, 0xc6, 0xd2, 0x9b, 0xb8
+};
+
+static const unsigned char ecjpake_test_X[] = {
+ 0x04, 0x52, 0xa4, 0xda, 0x90, 0xa5, 0x15, 0x7f, 0xc0, 0xe5, 0x1f, 0x79,
+ 0x4b, 0xe3, 0xbb, 0x3f, 0x1d, 0xf8, 0xdf, 0xb1, 0xe3, 0x18, 0xa8, 0x10,
+ 0xf2, 0x05, 0x2e, 0x64, 0xa8, 0xe8, 0x35, 0x64, 0xe8, 0xe2, 0x8c, 0x17,
+ 0x15, 0xab, 0xf7, 0x8d, 0x1f, 0x8b, 0x18, 0x99, 0x6d, 0x6a, 0xb7, 0xbd,
+ 0xcc, 0xbe, 0x52, 0x08, 0x1a, 0x3a, 0xe7, 0x65, 0x4b, 0xdf, 0x66, 0x62,
+ 0xf5, 0x74, 0xe0, 0xfd, 0x80
+};
+
+static const unsigned char ecjpake_test_h[] = {
+ 0xec, 0xf3, 0x24, 0x46, 0x16, 0xce, 0xa5, 0x34, 0x58, 0x46, 0xd2, 0x45,
+ 0xba, 0x27, 0x63, 0x36, 0x50, 0xc4, 0x70, 0x3d, 0x56, 0x0c, 0x7a, 0x7c,
+ 0x51, 0x69, 0xfe, 0xa7, 0xa3, 0xf7, 0x79, 0x10
+};
+
/*
* Checkup routine
*/
int mbedtls_ecjpake_self_test( int verbose )
{
int ret;
+ mbedtls_ecp_group grp;
+ mbedtls_ecp_point G, V, X;
+ mbedtls_mpi h, h_ref;
+ const mbedtls_md_info_t *md_info;
- ret = 0; /* XXX */
+ mbedtls_ecp_group_init( &grp );
+ mbedtls_ecp_point_init( &G );
+ mbedtls_ecp_point_init( &V );
+ mbedtls_ecp_point_init( &X );
+ mbedtls_mpi_init( &h_ref );
+ mbedtls_mpi_init( &h );
+
+ if( verbose != 0 )
+ mbedtls_printf( " ECJPAKE test #1 (hash): " );
+
+ md_info = mbedtls_md_info_from_type( MBEDTLS_MD_SHA256 );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_group_load( &grp, MBEDTLS_ECP_DP_SECP256R1 ) );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_point_read_binary( &grp, &G, ecjpake_test_G,
+ sizeof( ecjpake_test_G ) ) );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_point_read_binary( &grp, &V, ecjpake_test_V,
+ sizeof( ecjpake_test_V ) ) );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_point_read_binary( &grp, &X, ecjpake_test_X,
+ sizeof( ecjpake_test_X ) ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &h_ref, ecjpake_test_h,
+ sizeof( ecjpake_test_h ) ) );
+
+ MBEDTLS_MPI_CHK( ecjpake_hash( md_info, &grp, &G, &V, &X, "client", &h ) );
+
+ if( mbedtls_mpi_cmp_mpi( &h, &h_ref ) != 0 )
+ {
+ ret = 1;
+ goto cleanup;
+ }
+
+ if( verbose != 0 )
+ mbedtls_printf( "passed\n" );
+
+cleanup:
+ mbedtls_ecp_group_free( &grp );
+ mbedtls_ecp_point_free( &G );
+ mbedtls_ecp_point_free( &V );
+ mbedtls_ecp_point_free( &X );
+ mbedtls_mpi_free( &h_ref );
+ mbedtls_mpi_free( &h );
+
+ if( ret != 0 )
+ {
+ if( verbose != 0 )
+ mbedtls_printf( "failed\n" );
+
+ ret = 1;
+ }
if( verbose != 0 )
mbedtls_printf( "\n" );
@@ -57,6 +234,8 @@
return( ret );
}
+#endif /* MBEDTLS_ECP_DP_SECP256R1_ENABLED && MBEDTLS_SHA256_C */
+
#endif /* MBEDTLS_SELF_TEST */
#endif /* MBEDTLS_ECJPAKE_C */
