Bignum Mod: pass endianness as a parameter
The external representation before included more than just endianness
(like reading in Mongtomery curve scalars or converting hashes to
numbers in a standard compliant way).
These are higher level concepts and are out of scope for Bignum and for
the modulus structure.
Passing endianness as a parameter is a step towards removing it from the
modulus structure.
Signed-off-by: Janos Follath <janos.follath@arm.com>
diff --git a/library/bignum_mod.h b/library/bignum_mod.h
index f0ce3c4..e6da15f 100644
--- a/library/bignum_mod.h
+++ b/library/bignum_mod.h
@@ -181,11 +181,12 @@
* and will be padded to m->limbs). The data will be automatically converted
* into the appropriate internal representation based on the value of `m->int_rep`.
*
- * \param r The address of the residue related to \p m. It must have as
- * many limbs as the modulus \p m.
- * \param m The address of the modulus.
- * \param buf The input buffer to import from.
- * \param buflen The length in bytes of \p buf.
+ * \param r The address of the residue related to \p m. It must have as
+ * many limbs as the modulus \p m.
+ * \param m The address of the modulus.
+ * \param buf The input buffer to import from.
+ * \param buflen The length in bytes of \p buf.
+ * \param ext_rep The endianness of the number in the input buffer.
*
* \return \c 0 if successful.
* \return #MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL if \p X isn't
@@ -196,7 +197,8 @@
int mbedtls_mpi_mod_read( mbedtls_mpi_mod_residue *r,
const mbedtls_mpi_mod_modulus *m,
const unsigned char *buf,
- size_t buflen );
+ size_t buflen,
+ mbedtls_mpi_mod_ext_rep ext_rep );
/** Write residue data onto a buffer using public representation data.
*
@@ -206,11 +208,12 @@
* converted from the appropriate internal representation based on the
* value of `m->int_rep field`.
*
- * \param r The address of the residue related to \p m. It must have as
- * many limbs as the modulus \p m.
- * \param m The address of the modulus.
- * \param buf The output buffer to export to.
- * \param buflen The length in bytes of \p buf.
+ * \param r The address of the residue related to \p m. It must have as
+ * many limbs as the modulus \p m.
+ * \param m The address of the modulus.
+ * \param buf The output buffer to export to.
+ * \param buflen The length in bytes of \p buf.
+ * \param ext_rep The endianness in which the number should be written into the output buffer.
*
* \return \c 0 if successful.
* \return #MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL if \p buf isn't
@@ -221,7 +224,8 @@
int mbedtls_mpi_mod_write( const mbedtls_mpi_mod_residue *r,
const mbedtls_mpi_mod_modulus *m,
unsigned char *buf,
- size_t buflen );
+ size_t buflen,
+ mbedtls_mpi_mod_ext_rep ext_rep );
/* END MERGE SLOT 7 */
/* BEGIN MERGE SLOT 8 */