| /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
| * |
| * LibTomCrypt is a library that provides various cryptographic |
| * algorithms in a highly modular and flexible manner. |
| * |
| * The library is free for all purposes without any express |
| * guarantee it works. |
| * |
| * Tom St Denis, tomstdenis@iahu.ca, http://libtomcrypt.org |
| */ |
| #include "mycrypt.h" |
| |
| /* Integer to Octet I2OSP -- Tom St Denis */ |
| |
| #ifdef PKCS_1 |
| |
| /* always stores the same # of bytes, pads with leading zero bytes |
| as required |
| */ |
| int pkcs_1_i2osp(mp_int *n, unsigned long modulus_len, unsigned char *out) |
| { |
| int err; |
| unsigned long size; |
| |
| size = mp_unsigned_bin_size(n); |
| |
| if (size > modulus_len) { |
| return CRYPT_BUFFER_OVERFLOW; |
| } |
| |
| /* store it */ |
| zeromem(out, modulus_len); |
| if ((err = mp_to_unsigned_bin(n, out+(modulus_len-size))) != MP_OKAY) { |
| return mpi_to_ltc_error(err); |
| } |
| return CRYPT_OK; |
| } |
| |
| #endif /* PKCS_1 */ |
| |
