Include order of Curve25519 base point in curve data

This commit is contained in:
Nicholas Wilson 2016-05-16 15:15:45 +01:00 committed by Manuel Pégourié-Gonnard
parent f65379bc40
commit 54fc34ea68
2 changed files with 6 additions and 1 deletions

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@ -144,7 +144,7 @@ typedef struct
mbedtls_mpi A; /*!< 1. A in the equation, or 2. (A + 2) / 4 */
mbedtls_mpi B; /*!< 1. B in the equation, or 2. unused */
mbedtls_ecp_point G; /*!< generator of the (sub)group used */
mbedtls_mpi N; /*!< 1. the order of G, or 2. unused */
mbedtls_mpi N; /*!< the order of G */
size_t pbits; /*!< number of bits in P */
size_t nbits; /*!< number of bits in 1. P, or 2. private keys */
unsigned int h; /*!< internal: 1 if the constants are static */

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@ -670,6 +670,11 @@ static int ecp_use_curve25519( mbedtls_ecp_group *grp )
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &grp->P, &grp->P, 19 ) );
grp->pbits = mbedtls_mpi_bitlen( &grp->P );
/* N = 2^252 + 27742317777372353535851937790883648493 */
MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &grp->N, 16,
"14DEF9DEA2F79CD65812631A5CF5D3ED" ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( &grp->N, 252, 1 ) );
/* Y intentionaly not set, since we use x/z coordinates.
* This is used as a marker to identify Montgomery curves! */
MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &grp->G.X, 9 ) );