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comparison src/pk/pkcs1/pkcs_1_i2osp.c @ 191:1c15b283127b libtomcrypt-orig

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Import of libtomcrypt 1.02 with manual path rename rearrangement etc
author Matt Johnston <matt@ucc.asn.au>
date Fri, 06 May 2005 13:23:02 +0000
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children 39d5d58461d6
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143:5d99163f7e32 191:1c15b283127b
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, [email protected], http://libtomcrypt.org
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(mp_int *n, unsigned long modulus_len, unsigned char *out)
32 {
33 int err;
34 unsigned long size;
35
36 size = mp_unsigned_bin_size(n);
37
38 if (size > modulus_len) {
39 return CRYPT_BUFFER_OVERFLOW;
40 }
41
42 /* store it */
43 zeromem(out, modulus_len);
44 if ((err = mp_to_unsigned_bin(n, out+(modulus_len-size))) != MP_OKAY) {
45 return mpi_to_ltc_error(err);
46 }
47 return CRYPT_OK;
48 }
49
50 #endif /* PKCS_1 */
51