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@gmail.com, http://libtomcrypt.com 10 */ 11 #include "tomcrypt.h" 12 13 /** 14 @file der_length_octet_string.c 15 ASN.1 DER, get length of OCTET STRING, Tom St Denis 16 */ 17 18 #ifdef LTC_DER 19 /** 20 Gets length of DER encoding of OCTET STRING 21 @param noctets The number of octets in the string to encode 22 @param outlen [out] The length of the DER encoding for the given string 23 @return CRYPT_OK if successful 24 */ der_length_octet_string(unsigned long noctets,unsigned long * outlen)25int der_length_octet_string(unsigned long noctets, unsigned long *outlen) 26 { 27 LTC_ARGCHK(outlen != NULL); 28 29 if (noctets < 128) { 30 /* 04 LL DD DD DD ... */ 31 *outlen = 2 + noctets; 32 } else if (noctets < 256) { 33 /* 04 81 LL DD DD DD ... */ 34 *outlen = 3 + noctets; 35 } else if (noctets < 65536UL) { 36 /* 04 82 LL LL DD DD DD ... */ 37 *outlen = 4 + noctets; 38 } else if (noctets < 16777216UL) { 39 /* 04 83 LL LL LL DD DD DD ... */ 40 *outlen = 5 + noctets; 41 } else { 42 return CRYPT_INVALID_ARG; 43 } 44 45 return CRYPT_OK; 46 } 47 48 #endif 49 50 51 /* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/octet/der_length_octet_string.c,v $ */ 52 /* $Revision: 1.2 $ */ 53 /* $Date: 2006/03/31 14:15:35 $ */ 54