Added support for writing points compressed
diff --git a/include/polarssl/ecp.h b/include/polarssl/ecp.h
index a875d7e..cd4dd9b 100644
--- a/include/polarssl/ecp.h
+++ b/include/polarssl/ecp.h
@@ -115,6 +115,12 @@
*/
#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
extern "C" {
#endif
@@ -210,17 +216,18 @@
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 P Point to export
+ * \param format Point format, should be a POLARSSL_ECP_PF_XXX macro
* \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,
+int ecp_write_binary( const ecp_group *grp, const ecp_point *P, int format,
size_t *olen, unsigned char *buf, size_t buflen );
/**
diff --git a/library/ecp.c b/library/ecp.c
index 854da58..6501fbe 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -174,16 +174,20 @@
}
/*
- * 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 )
{
int ret;
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 )
{
@@ -197,14 +201,28 @@
}
plen = mpi_size( &grp->P );
- *olen = 2 * plen + 1;
- if( buflen < *olen )
- return( POLARSSL_ERR_ECP_GENERIC );
+ if( format == POLARSSL_ECP_PF_UNCOMPRESSED )
+ {
+ *olen = 2 * plen + 1;
- buf[0] = 0x04;
- MPI_CHK( mpi_write_binary( &P->X, buf + 1, plen ) );
- MPI_CHK( mpi_write_binary( &P->Y, buf + 1 + plen, plen ) );
+ 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 ) );
+ }
+ 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:
return( ret );
diff --git a/tests/suites/test_suite_ecp.data b/tests/suites/test_suite_ecp.data
index 20ae3cd..e84ac04 100644
--- a/tests/suites/test_suite_ecp.data
+++ b/tests/suites/test_suite_ecp.data
@@ -133,17 +133,35 @@
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 #0 (zero, bad format)
+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: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:SECP192R1:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"6ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":"01":"0448d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc99336ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":49:0
+ECP write binary #3 (non-zero, uncompressed, buffer just fits)
+ecp_write_binary:SECP192R1:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"6ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":"01":UNCOMPRESSED:"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 write binary #4 (non-zero, uncompressed, buffer too small)
+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_fast_mod:SECP192R1:"000000000000010500000000000001040000000000000103000000000000010200000000000001010000000000000100"
diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function
index 1e50499..b273a70 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -225,7 +225,7 @@
END_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_point P;
@@ -243,13 +243,13 @@
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} );
+#define POLARSSL_ECP_PF_UNKNOWN -1
+ TEST_ASSERT( ecp_write_binary( &grp, &P, POLARSSL_ECP_PF_{format},
+ &olen, buf, {blen} ) == {ret} );
if( {ret} == 0 )
{
- TEST_ASSERT( olen == strlen({out}) / 2 );
-
- hexify( str, buf, {blen} );
+ hexify( str, buf, olen );
TEST_ASSERT( strcasecmp( (char *) str, {out} ) == 0 );
}