53 lines
1.8 KiB
C
53 lines
1.8 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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#include "tomcrypt_private.h"
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#ifdef LTC_MDH
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/**
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Export a DH key to a binary packet
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@param out [out] The destination for the key
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@param outlen [in/out] The max size and resulting size of the DH key
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@param type Which type of key (PK_PRIVATE or PK_PUBLIC)
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@param key The key you wish to export
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@return CRYPT_OK if successful
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*/
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int dh_export(unsigned char *out, unsigned long *outlen, int type, const dh_key *key)
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{
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unsigned char flags[1];
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int err;
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unsigned long version = 0;
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LTC_ARGCHK(out != NULL);
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LTC_ARGCHK(outlen != NULL);
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LTC_ARGCHK(key != NULL);
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if (type == PK_PRIVATE) {
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/* export x - private key */
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flags[0] = 1;
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err = der_encode_sequence_multi(out, outlen,
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LTC_ASN1_SHORT_INTEGER, 1UL, &version,
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LTC_ASN1_BIT_STRING, 1UL, flags,
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LTC_ASN1_INTEGER, 1UL, key->prime,
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LTC_ASN1_INTEGER, 1UL, key->base,
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LTC_ASN1_INTEGER, 1UL, key->x,
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LTC_ASN1_EOL, 0UL, NULL);
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}
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else {
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/* export y - public key */
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flags[0] = 0;
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err = der_encode_sequence_multi(out, outlen,
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LTC_ASN1_SHORT_INTEGER, 1UL, &version,
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LTC_ASN1_BIT_STRING, 1UL, flags,
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LTC_ASN1_INTEGER, 1UL, key->prime,
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LTC_ASN1_INTEGER, 1UL, key->base,
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LTC_ASN1_INTEGER, 1UL, key->y,
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LTC_ASN1_EOL, 0UL, NULL);
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}
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return err;
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}
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#endif /* LTC_MDH */
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