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comparison libtomcrypt/src/pk/asn1/der/integer/der_length_integer.c @ 1471:6dba84798cd5

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Update to libtomcrypt 1.18.1, merged with Dropbear changes
author Matt Johnston <matt@ucc.asn.au>
date Fri, 09 Feb 2018 21:44:05 +0800
parents f849a5ca2efc
children
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1470:8bba51a55704 1471:6dba84798cd5
3 * LibTomCrypt is a library that provides various cryptographic 3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner. 4 * algorithms in a highly modular and flexible manner.
5 * 5 *
6 * The library is free for all purposes without any express 6 * The library is free for all purposes without any express
7 * guarantee it works. 7 * guarantee it works.
8 *
9 * Tom St Denis, [email protected], http://libtom.org
10 */ 8 */
11 #include "tomcrypt.h" 9 #include "tomcrypt.h"
12 10
13 /** 11 /**
14 @file der_length_integer.c 12 @file der_length_integer.c
16 */ 14 */
17 15
18 16
19 #ifdef LTC_DER 17 #ifdef LTC_DER
20 /** 18 /**
21 Gets length of DER encoding of num 19 Gets length of DER encoding of num
22 @param num The int to get the size of 20 @param num The int to get the size of
23 @param outlen [out] The length of the DER encoding for the given integer 21 @param outlen [out] The length of the DER encoding for the given integer
24 @return CRYPT_OK if successful 22 @return CRYPT_OK if successful
25 */ 23 */
26 int der_length_integer(void *num, unsigned long *outlen) 24 int der_length_integer(void *num, unsigned long *outlen)
27 { 25 {
44 /* size for bignum */ 42 /* size for bignum */
45 z = len = leading_zero + mp_unsigned_bin_size(num); 43 z = len = leading_zero + mp_unsigned_bin_size(num);
46 } else { 44 } else {
47 /* it's negative */ 45 /* it's negative */
48 /* find power of 2 that is a multiple of eight and greater than count bits */ 46 /* find power of 2 that is a multiple of eight and greater than count bits */
49 leading_zero = 0;
50 z = mp_count_bits(num); 47 z = mp_count_bits(num);
51 z = z + (8 - (z & 7)); 48 z = z + (8 - (z & 7));
52 if (((mp_cnt_lsb(num)+1)==mp_count_bits(num)) && ((mp_count_bits(num)&7)==0)) --z; 49 if (((mp_cnt_lsb(num)+1)==mp_count_bits(num)) && ((mp_count_bits(num)&7)==0)) --z;
53 len = z = z >> 3; 50 len = z = z >> 3;
54 } 51 }
69 66
70 /* we need a 0x02 to indicate it's INTEGER */ 67 /* we need a 0x02 to indicate it's INTEGER */
71 ++len; 68 ++len;
72 69
73 /* return length */ 70 /* return length */
74 *outlen = len; 71 *outlen = len;
75 return CRYPT_OK; 72 return CRYPT_OK;
76 } 73 }
77 74
78 #endif 75 #endif
79 76
80 /* $Source$ */ 77 /* ref: $Format:%D$ */
81 /* $Revision$ */ 78 /* git commit: $Format:%H$ */
82 /* $Date$ */ 79 /* commit time: $Format:%ai$ */