Added support for writing points compressed

This commit is contained in:
Manuel Pégourié-Gonnard 2012-11-24 15:19:55 +01:00 committed by Paul Bakker
parent e19feb5b46
commit 37d218a8e3
4 changed files with 66 additions and 23 deletions

View file

@ -115,6 +115,12 @@ ecp_group;
*/ */
#define POLARSSL_ECP_WINDOW_SIZE 7 /**< Maximum NAF width used. */ #define POLARSSL_ECP_WINDOW_SIZE 7 /**< Maximum NAF width used. */
/*
* Point formats
*/
#define POLARSSL_ECP_PF_UNCOMPRESSED 0 /**< Uncompressed point format */
#define POLARSSL_ECP_PF_COMPRESSED 1 /**< Compressed point format */
#ifdef __cplusplus #ifdef __cplusplus
extern "C" { extern "C" {
#endif #endif
@ -210,17 +216,18 @@ int ecp_group_read_string( ecp_group *grp, int radix,
const char *gx, const char *gy, const char *n); const char *gx, const char *gy, const char *n);
/** /**
* \brief Export a point into unsigned binary data, uncompressed * \brief Export a point into unsigned binary data
* *
* \param grp Group the point belongs to * \param grp Group the point belongs to
* \param P Point to export * \param P Point to export
* \param format Point format, should be a POLARSSL_ECP_PF_XXX macro
* \param olen Length of the actual ouput * \param olen Length of the actual ouput
* \param buf Output buffer * \param buf Output buffer
* \param buflen Length of the output buffer * \param buflen Length of the output buffer
* *
* \return 0 if successful, or POLARSSL_ERR_ECP_GENERIC * \return 0 if successful, or POLARSSL_ERR_ECP_GENERIC
*/ */
int ecp_write_binary( const ecp_group *grp, const ecp_point *P, int ecp_write_binary( const ecp_group *grp, const ecp_point *P, int format,
size_t *olen, unsigned char *buf, size_t buflen ); size_t *olen, unsigned char *buf, size_t buflen );
/** /**

View file

@ -174,16 +174,20 @@ cleanup:
} }
/* /*
* Export a point into unsigned binary data, uncompressed format (SEC1 2.3.3) * Export a point into unsigned binary data (SEC1 2.3.3)
*/ */
int ecp_write_binary( const ecp_group *grp, const ecp_point *P, int ecp_write_binary( const ecp_group *grp, const ecp_point *P, int format,
size_t *olen, unsigned char *buf, size_t buflen ) size_t *olen, unsigned char *buf, size_t buflen )
{ {
int ret; int ret;
size_t plen; size_t plen;
if( format != POLARSSL_ECP_PF_UNCOMPRESSED &&
format != POLARSSL_ECP_PF_COMPRESSED )
return( POLARSSL_ERR_ECP_GENERIC );
/* /*
* Case P == 0 * Common case: P == 0
*/ */
if( mpi_cmp_int( &P->Z, 0 ) == 0 ) if( mpi_cmp_int( &P->Z, 0 ) == 0 )
{ {
@ -197,14 +201,28 @@ int ecp_write_binary( const ecp_group *grp, const ecp_point *P,
} }
plen = mpi_size( &grp->P ); plen = mpi_size( &grp->P );
*olen = 2 * plen + 1;
if( buflen < *olen ) if( format == POLARSSL_ECP_PF_UNCOMPRESSED )
return( POLARSSL_ERR_ECP_GENERIC ); {
*olen = 2 * plen + 1;
buf[0] = 0x04; if( buflen < *olen )
MPI_CHK( mpi_write_binary( &P->X, buf + 1, plen ) ); return( POLARSSL_ERR_ECP_GENERIC );
MPI_CHK( mpi_write_binary( &P->Y, buf + 1 + plen, plen ) );
buf[0] = 0x04;
MPI_CHK( mpi_write_binary( &P->X, buf + 1, plen ) );
MPI_CHK( mpi_write_binary( &P->Y, buf + 1 + plen, plen ) );
}
else if( format == POLARSSL_ECP_PF_COMPRESSED )
{
*olen = plen + 1;
if( buflen < *olen )
return( POLARSSL_ERR_ECP_GENERIC );
buf[0] = 0x02 + mpi_get_bit( &P->Y, 0 );
MPI_CHK( mpi_write_binary( &P->X, buf + 1, plen ) );
}
cleanup: cleanup:
return( ret ); return( ret );

View file

@ -133,17 +133,35 @@ ecp_small_check_pub:0:2:1:0
ECP small check pubkey #10 ECP small check pubkey #10
ecp_small_check_pub:10:25:1:POLARSSL_ERR_ECP_GENERIC ecp_small_check_pub:10:25:1:POLARSSL_ERR_ECP_GENERIC
ECP write binary #1 (zero, buffer just fits) ECP write binary #0 (zero, bad format)
ecp_write_binary:SECP192R1:"01":"01":"00":"00":1:0 ecp_write_binary:SECP192R1:"01":"01":"00":UNKNOWN:"00":1:POLARSSL_ERR_ECP_GENERIC
ECP write binary #1 (zero, uncompressed, buffer just fits)
ecp_write_binary:SECP192R1:"01":"01":"00":UNCOMPRESSED:"00":1:0
ECP write binary #2 (zero, buffer too small) ECP write binary #2 (zero, buffer too small)
ecp_write_binary:SECP192R1:"01":"01":"00":"00":0:POLARSSL_ERR_ECP_GENERIC ecp_write_binary:SECP192R1:"01":"01":"00":UNCOMPRESSED:"00":0:POLARSSL_ERR_ECP_GENERIC
ECP write binary #3 (non-zero, buffer just fits) ECP write binary #3 (non-zero, uncompressed, buffer just fits)
ecp_write_binary:SECP192R1:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"6ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":"01":"0448d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc99336ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":49:0 ecp_write_binary:SECP192R1:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"6ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":"01":UNCOMPRESSED:"0448d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc99336ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":49:0
ECP write binary #4 (non-zero, buffer too small) ECP write binary #4 (non-zero, uncompressed, buffer too small)
ecp_write_binary:SECP192R1:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"6ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":"01":"0448d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc99336ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":48:POLARSSL_ERR_ECP_GENERIC ecp_write_binary:SECP192R1:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"6ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":"01":UNCOMPRESSED:"0448d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc99336ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":48:POLARSSL_ERR_ECP_GENERIC
ECP write binary #5 (zero, compressed, buffer just fits)
ecp_write_binary:SECP192R1:"01":"01":"00":COMPRESSED:"00":1:0
ECP write binary #6 (zero, buffer too small)
ecp_write_binary:SECP192R1:"01":"01":"00":COMPRESSED:"00":0:POLARSSL_ERR_ECP_GENERIC
ECP write binary #7 (even, compressed, buffer just fits)
ecp_write_binary:SECP192R1:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"6ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":"01":COMPRESSED:"0248d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":25:0
ECP write binary #8 (even, compressed, buffer too small)
ecp_write_binary:SECP192R1:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"6ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":"01":COMPRESSED:"0248d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":24:POLARSSL_ERR_ECP_GENERIC
ECP write binary #7 (odd, compressed, buffer just fits)
ecp_write_binary:SECP192R1:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"93112b28345b7d1d7799611e49bea9d8290cb2d7afe1f9f3":"01":COMPRESSED:"0348d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":25:0
ECP mod p192 readable ECP mod p192 readable
ecp_fast_mod:SECP192R1:"000000000000010500000000000001040000000000000103000000000000010200000000000001010000000000000100" ecp_fast_mod:SECP192R1:"000000000000010500000000000001040000000000000103000000000000010200000000000001010000000000000100"

View file

@ -225,7 +225,7 @@ ecp_fast_mod:id:N
END_CASE END_CASE
BEGIN_CASE BEGIN_CASE
ecp_write_binary:id:x:y:z:out:blen:ret ecp_write_binary:id:x:y:z:format:out:blen:ret
{ {
ecp_group grp; ecp_group grp;
ecp_point P; ecp_point P;
@ -243,13 +243,13 @@ ecp_write_binary:id:x:y:z:out:blen:ret
TEST_ASSERT( mpi_read_string( &P.Y, 16, {y} ) == 0 ); TEST_ASSERT( mpi_read_string( &P.Y, 16, {y} ) == 0 );
TEST_ASSERT( mpi_read_string( &P.Z, 16, {z} ) == 0 ); TEST_ASSERT( mpi_read_string( &P.Z, 16, {z} ) == 0 );
TEST_ASSERT( ecp_write_binary( &grp, &P, &olen, buf, {blen} ) == {ret} ); #define POLARSSL_ECP_PF_UNKNOWN -1
TEST_ASSERT( ecp_write_binary( &grp, &P, POLARSSL_ECP_PF_{format},
&olen, buf, {blen} ) == {ret} );
if( {ret} == 0 ) if( {ret} == 0 )
{ {
TEST_ASSERT( olen == strlen({out}) / 2 ); hexify( str, buf, olen );
hexify( str, buf, {blen} );
TEST_ASSERT( strcasecmp( (char *) str, {out} ) == 0 ); TEST_ASSERT( strcasecmp( (char *) str, {out} ) == 0 );
} }