3
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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 "mycrypt.h" |
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12 |
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13 #ifdef MDSA |
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14 |
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15 int dsa_export(unsigned char *out, unsigned long *outlen, int type, dsa_key *key) |
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16 { |
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17 unsigned long y, z; |
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18 int err; |
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19 |
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20 _ARGCHK(out != NULL); |
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21 _ARGCHK(outlen != NULL); |
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22 _ARGCHK(key != NULL); |
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23 |
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24 /* can we store the static header? */ |
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25 if (*outlen < (PACKET_SIZE + 1 + 2)) { |
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26 return CRYPT_BUFFER_OVERFLOW; |
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27 } |
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28 |
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29 if (type == PK_PRIVATE && key->type != PK_PRIVATE) { |
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30 return CRYPT_PK_TYPE_MISMATCH; |
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31 } |
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32 |
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33 if (type != PK_PUBLIC && type != PK_PRIVATE) { |
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34 return CRYPT_INVALID_ARG; |
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35 } |
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36 |
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37 /* store header */ |
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38 packet_store_header(out, PACKET_SECT_DSA, PACKET_SUB_KEY); |
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39 y = PACKET_SIZE; |
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40 |
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41 /* store g, p, q, qord */ |
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42 out[y++] = type; |
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43 out[y++] = (key->qord>>8)&255; |
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44 out[y++] = key->qord & 255; |
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45 |
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46 OUTPUT_BIGNUM(&key->g,out,y,z); |
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47 OUTPUT_BIGNUM(&key->p,out,y,z); |
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48 OUTPUT_BIGNUM(&key->q,out,y,z); |
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49 |
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50 /* public exponent */ |
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51 OUTPUT_BIGNUM(&key->y,out,y,z); |
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52 |
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53 if (type == PK_PRIVATE) { |
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54 OUTPUT_BIGNUM(&key->x,out,y,z); |
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55 } |
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56 |
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57 *outlen = y; |
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58 return CRYPT_OK; |
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59 } |
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60 |
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61 #endif |
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62 |