/* 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 */