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Added ecp_write_binary().

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Manuel Pégourié-Gonnard 2012-11-24 14:10:14 +01:00 committed by Paul Bakker
parent 1c33057a63
commit e19feb5b46
4 changed files with 96 additions and 0 deletions
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14
include/polarssl/ecp.h
View File

@ -209,6 +209,20 @@ int ecp_group_read_string( ecp_group *grp, int radix,
const char *p, const char *b,
const char *gx, const char *gy, const char *n);
/**
* \brief Export a point into unsigned binary data, uncompressed
*
* \param grp Group the point belongs to
* \param P Point to export
* \param olen Length of the actual ouput
* \param buf Output buffer
* \param buflen Length of the output buffer
*
* \return 0 if successful, or POLARSSL_ERR_ECP_GENERIC
*/
int ecp_write_binary( const ecp_group *grp, const ecp_point *P,
size_t *olen, unsigned char *buf, size_t buflen );
/**
* \brief Set a group using well-known domain parameters
*

37
library/ecp.c
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@ -173,6 +173,43 @@ cleanup:
return( ret );
}
/*
* Export a point into unsigned binary data, uncompressed format (SEC1 2.3.3)
*/
int ecp_write_binary( const ecp_group *grp, const ecp_point *P,
size_t *olen, unsigned char *buf, size_t buflen )
{
int ret;
size_t plen;
/*
* Case P == 0
*/
if( mpi_cmp_int( &P->Z, 0 ) == 0 )
{
if( buflen < 1 )
return( POLARSSL_ERR_ECP_GENERIC );
buf[0] = 0x00;
*olen = 1;
return( 0 );
}
plen = mpi_size( &grp->P );
*olen = 2 * plen + 1;
if( buflen < *olen )
return( POLARSSL_ERR_ECP_GENERIC );
buf[0] = 0x04;
MPI_CHK( mpi_write_binary( &P->X, buf + 1, plen ) );
MPI_CHK( mpi_write_binary( &P->Y, buf + 1 + plen, plen ) );
cleanup:
return( ret );
}
/*
* Wrapper around fast quasi-modp functions, with fall-back to mpi_mod_mpi.
* See the documentation of struct ecp_group.

12
tests/suites/test_suite_ecp.data
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@ -133,6 +133,18 @@ ecp_small_check_pub:0:2:1:0
ECP small check pubkey #10
ecp_small_check_pub:10:25:1:POLARSSL_ERR_ECP_GENERIC
ECP write binary #1 (zero, buffer just fits)
ecp_write_binary:SECP192R1:"01":"01":"00":"00":1:0
ECP write binary #2 (zero, buffer too small)
ecp_write_binary:SECP192R1:"01":"01":"00":"00":0:POLARSSL_ERR_ECP_GENERIC
ECP write binary #3 (non-zero, buffer just fits)
ecp_write_binary:SECP192R1:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"6ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":"01":"0448d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc99336ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":49:0
ECP write binary #4 (non-zero, buffer too small)
ecp_write_binary:SECP192R1:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"6ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":"01":"0448d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc99336ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":48:POLARSSL_ERR_ECP_GENERIC
ECP mod p192 readable
ecp_fast_mod:SECP192R1:"000000000000010500000000000001040000000000000103000000000000010200000000000001010000000000000100"

33
tests/suites/test_suite_ecp.function
View File

@ -224,6 +224,39 @@ ecp_fast_mod:id:N
}
END_CASE
BEGIN_CASE
ecp_write_binary:id:x:y:z:out:blen:ret
{
ecp_group grp;
ecp_point P;
unsigned char buf[256], str[512];
size_t olen;
memset( buf, 0, sizeof( buf ) );
memset( str, 0, sizeof( str ) );
ecp_group_init( &grp ); ecp_point_init( &P );
TEST_ASSERT( ecp_use_known_dp( &grp, POLARSSL_ECP_DP_{id} ) == 0 );
TEST_ASSERT( mpi_read_string( &P.X, 16, {x} ) == 0 );
TEST_ASSERT( mpi_read_string( &P.Y, 16, {y} ) == 0 );
TEST_ASSERT( mpi_read_string( &P.Z, 16, {z} ) == 0 );
TEST_ASSERT( ecp_write_binary( &grp, &P, &olen, buf, {blen} ) == {ret} );
if( {ret} == 0 )
{
TEST_ASSERT( olen == strlen({out}) / 2 );
hexify( str, buf, {blen} );
TEST_ASSERT( strcasecmp( (char *) str, {out} ) == 0 );
}
ecp_group_free( &grp ); ecp_point_free( &P );
}
END_CASE
BEGIN_CASE
ecp_selftest:
{