1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis 2 * 3 * LibTomCrypt is a library that provides various cryptographic 4 * algorithms in a highly modular and flexible manner. 5 * 6 * The library is free for all purposes without any express 7 * guarantee it works. 8 * 9 * Tom St Denis, tomstdenis (at) gmail.com, http://libtomcrypt.com 10 */ 11 #include "tomcrypt.h" 12 13 /** 14 @file pkcs_1_i2osp.c 15 Integer to Octet I2OSP, Tom St Denis 16 */ 17 18 #ifdef PKCS_1 19 20 /* always stores the same # of bytes, pads with leading zero bytes 21 as required 22 */ 23 24 /** 25 PKCS #1 Integer to binary 26 @param n The integer to store 27 @param modulus_len The length of the RSA modulus 28 @param out [out] The destination for the integer 29 @return CRYPT_OK if successful 30 */ 31 int pkcs_1_i2osp(void *n, unsigned long modulus_len, unsigned char *out) 32 { 33 unsigned long size; 34 35 size = mp_unsigned_bin_size(n); 36 37 if (size > modulus_len) { 38 return CRYPT_BUFFER_OVERFLOW; 39 } 40 41 /* store it */ 42 zeromem(out, modulus_len); 43 return mp_to_unsigned_bin(n, out+(modulus_len-size)); 44 } 45 46 #endif /* PKCS_1 */ 47 48 49 /* $Source: /cvs/libtom/libtomcrypt/src/pk/pkcs1/pkcs_1_i2osp.c,v $ */ 50 /* $Revision: 1.5 $ */ 51 /* $Date: 2006/03/31 14:15:35 $ */ 52
