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1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
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2 * |
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3 * LibTomCrypt is a library that provides various cryptographic |
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4 * algorithms in a highly modular and flexible manner. |
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5 * |
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6 * The library is free for all purposes without any express |
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7 * guarantee it works. |
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8 * |
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9 * Tom St Denis, [email protected], http://libtomcrypt.org |
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10 */ |
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11 #include "tomcrypt.h" |
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12 |
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13 /** |
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14 @file der_length_octet_string.c |
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15 ASN.1 DER, get length of OCTET STRING, Tom St Denis |
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16 */ |
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17 |
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18 #ifdef LTC_DER |
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19 /** |
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20 Gets length of DER encoding of OCTET STRING |
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21 @param noctets The number of octets in the string to encode |
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22 @param outlen [out] The length of the DER encoding for the given string |
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23 @return CRYPT_OK if successful |
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24 */ |
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25 int der_length_octet_string(unsigned long noctets, unsigned long *outlen) |
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26 { |
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27 LTC_ARGCHK(outlen != NULL); |
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28 |
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29 if (noctets < 128) { |
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30 /* 04 LL DD DD DD ... */ |
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31 *outlen = 2 + noctets; |
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32 } else if (noctets < 256) { |
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33 /* 04 81 LL DD DD DD ... */ |
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34 *outlen = 3 + noctets; |
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35 } else if (noctets < 65536UL) { |
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36 /* 04 82 LL LL DD DD DD ... */ |
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37 *outlen = 4 + noctets; |
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38 } else if (noctets < 16777216UL) { |
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39 /* 04 83 LL LL LL DD DD DD ... */ |
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40 *outlen = 5 + noctets; |
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41 } else { |
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42 return CRYPT_INVALID_ARG; |
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43 } |
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44 |
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45 return CRYPT_OK; |
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46 } |
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47 |
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48 #endif |
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49 |
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50 |
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51 /* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/octet/der_length_octet_string.c,v $ */ |
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52 /* $Revision: 1.1 $ */ |
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53 /* $Date: 2005/05/16 15:08:11 $ */ |
