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76a4b576e5
This introduces a third system of elliptic curve representation and arithmetic, namely Edwards form.
80 lines
1.9 KiB
C
80 lines
1.9 KiB
C
/*
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* EC key generation.
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*/
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#include "ssh.h"
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/* Forward reference from sshecc.c */
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struct ec_point *ecp_mul(const struct ec_point *a, const Bignum b);
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int ec_generate(struct ec_key *key, int bits, progfn_t pfn,
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void *pfnparam)
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{
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struct ec_point *publicKey;
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if (bits == 256) {
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key->publicKey.curve = ec_p256();
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} else if (bits == 384) {
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key->publicKey.curve = ec_p384();
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} else if (bits == 521) {
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key->publicKey.curve = ec_p521();
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} else {
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return 0;
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}
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key->privateKey = bignum_random_in_range(One, key->publicKey.curve->w.n);
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if (!key->privateKey) return 0;
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publicKey = ec_public(key->privateKey, key->publicKey.curve);
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if (!publicKey) {
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freebn(key->privateKey);
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key->privateKey = NULL;
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return 0;
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}
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key->publicKey.x = publicKey->x;
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key->publicKey.y = publicKey->y;
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key->publicKey.z = NULL;
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sfree(publicKey);
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return 1;
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}
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int ec_edgenerate(struct ec_key *key, int bits, progfn_t pfn,
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void *pfnparam)
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{
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struct ec_point *publicKey;
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if (bits == 256) {
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key->publicKey.curve = ec_ed25519();
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} else {
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return 0;
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}
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{
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/* EdDSA secret keys are just 32 bytes of hash preimage; the
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* 64-byte SHA-512 hash of that key will be used when signing,
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* but the form of the key stored on disk is the preimage
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* only. */
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Bignum privMax = bn_power_2(bits);
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if (!privMax) return 0;
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key->privateKey = bignum_random_in_range(Zero, privMax);
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freebn(privMax);
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if (!key->privateKey) return 0;
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}
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publicKey = ec_public(key->privateKey, key->publicKey.curve);
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if (!publicKey) {
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freebn(key->privateKey);
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key->privateKey = NULL;
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return 0;
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}
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key->publicKey.x = publicKey->x;
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key->publicKey.y = publicKey->y;
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key->publicKey.z = NULL;
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sfree(publicKey);
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return 1;
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}
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