/* LibTomCrypt, modular cryptographic library -- Tom St Denis */ /* SPDX-License-Identifier: Unlicense */ #include "tomcrypt_private.h" /** @file pkcs_1_i2osp.c Integer to Octet I2OSP, Tom St Denis */ #ifdef LTC_PKCS_1 /* always stores the same # of bytes, pads with leading zero bytes as required */ /** PKCS #1 Integer to binary @param n The integer to store @param modulus_len The length of the RSA modulus @param out [out] The destination for the integer @return CRYPT_OK if successful */ int pkcs_1_i2osp(void *n, unsigned long modulus_len, unsigned char *out) { unsigned long size; size = mp_unsigned_bin_size(n); if (size > modulus_len) { return CRYPT_BUFFER_OVERFLOW; } /* store it */ zeromem(out, modulus_len); return mp_to_unsigned_bin(n, out+(modulus_len-size)); } #endif /* LTC_PKCS_1 */