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Add functions for read/write ECPoint records

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This commit is contained in:
Manuel Pégourié-Gonnard
2013-02-09 19:00:07 +01:00
parent 1a96728964
commit 0079405918
2 changed files with 89 additions and 12 deletions
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53
library/ecp.c
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@ -186,14 +186,14 @@ cleanup:
* Export a point into unsigned binary data (SEC1 2.3.3)
*/
int ecp_write_binary( const ecp_group *grp, const ecp_point *P, int format,
size_t *olen, unsigned char *buf, size_t buflen )
uint8_t *olen, unsigned char *buf, size_t buflen )
{
int ret;
size_t plen;
if( format != POLARSSL_ECP_PF_UNCOMPRESSED &&
format != POLARSSL_ECP_PF_COMPRESSED )
return( POLARSSL_ERR_ECP_GENERIC );
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
/*
* Common case: P == 0
@ -201,7 +201,7 @@ int ecp_write_binary( const ecp_group *grp, const ecp_point *P, int format,
if( mpi_cmp_int( &P->Z, 0 ) == 0 )
{
if( buflen < 1 )
return( POLARSSL_ERR_ECP_GENERIC );
return( POLARSSL_ERR_ECP_BUFFER_TOO_SMALL );
buf[0] = 0x00;
*olen = 1;
@ -216,7 +216,7 @@ int ecp_write_binary( const ecp_group *grp, const ecp_point *P, int format,
*olen = 2 * plen + 1;
if( buflen < *olen )
return( POLARSSL_ERR_ECP_GENERIC );
return( POLARSSL_ERR_ECP_BUFFER_TOO_SMALL );
buf[0] = 0x04;
MPI_CHK( mpi_write_binary( &P->X, buf + 1, plen ) );
@ -227,7 +227,7 @@ int ecp_write_binary( const ecp_group *grp, const ecp_point *P, int format,
*olen = plen + 1;
if( buflen < *olen )
return( POLARSSL_ERR_ECP_GENERIC );
return( POLARSSL_ERR_ECP_BUFFER_TOO_SMALL );
buf[0] = 0x02 + mpi_get_bit( &P->Y, 0 );
MPI_CHK( mpi_write_binary( &P->X, buf + 1, plen ) );
@ -264,6 +264,49 @@ cleanup:
return( ret );
}
/*
* Import a point from a TLS ECPoint record (RFC 4492)
* struct {
* opaque point <1..2^8-1>;
* } ECPoint;
*/
int ecp_tls_read_point( const ecp_group *grp, ecp_point *pt,
const unsigned char *buf, size_t buf_len )
{
unsigned char data_len;
/*
* We must have at least two bytes (1 for length, at least of for data)
*/
if( buf_len < 2 )
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
data_len = *buf++;
if( data_len < 1 || data_len > buf_len - 1 )
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
return ecp_read_binary( grp, pt, POLARSSL_ECP_PF_UNCOMPRESSED,
buf, data_len );
}
/*
* Export a point as a TLS ECPoint record (RFC 4492)
* struct {
* opaque point <1..2^8-1>;
* } ECPoint;
*/
int ecp_tls_write_point( const ecp_group *grp, const ecp_point *pt,
int format, unsigned char *buf, size_t buf_len )
{
/*
* buf_len must be at least one, for our length byte
*/
if( buf_len < 1 )
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
return ecp_write_binary( grp, pt, format, buf, buf + 1, buf_len - 1);
}
/*
* Wrapper around fast quasi-modp functions, with fall-back to mpi_mod_mpi.
* See the documentation of struct ecp_group.