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-rw-r--r--src/key.cpp117
1 files changed, 117 insertions, 0 deletions
diff --git a/src/key.cpp b/src/key.cpp
new file mode 100644
index 0000000000..400b1887c5
--- /dev/null
+++ b/src/key.cpp
@@ -0,0 +1,117 @@
+// Copyright (c) 2011 The Bitcoin developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file license.txt or http://www.opensource.org/licenses/mit-license.php.
+
+#include <openssl/ec.h>
+#include <openssl/ecdsa.h>
+
+// Generate a private key from just the secret parameter
+int EC_KEY_regenerate_key(EC_KEY *eckey, BIGNUM *priv_key)
+{
+ int ok = 0;
+ BN_CTX *ctx = NULL;
+ EC_POINT *pub_key = NULL;
+
+ if (!eckey) return 0;
+
+ const EC_GROUP *group = EC_KEY_get0_group(eckey);
+
+ if ((ctx = BN_CTX_new()) == NULL)
+ goto err;
+
+ pub_key = EC_POINT_new(group);
+
+ if (pub_key == NULL)
+ goto err;
+
+ if (!EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, ctx))
+ goto err;
+
+ EC_KEY_set_private_key(eckey,priv_key);
+ EC_KEY_set_public_key(eckey,pub_key);
+
+ ok = 1;
+
+err:
+
+ if (pub_key)
+ EC_POINT_free(pub_key);
+ if (ctx != NULL)
+ BN_CTX_free(ctx);
+
+ return(ok);
+}
+
+// Perform ECDSA key recovery (see SEC1 4.1.6) for curves over (mod p)-fields
+// recid selects which key is recovered
+// if check is nonzero, additional checks are performed
+int ECDSA_SIG_recover_key_GFp(EC_KEY *eckey, ECDSA_SIG *ecsig, const unsigned char *msg, int msglen, int recid, int check)
+{
+ if (!eckey) return 0;
+
+ int ret = 0;
+ BN_CTX *ctx = NULL;
+
+ BIGNUM *x = NULL;
+ BIGNUM *e = NULL;
+ BIGNUM *order = NULL;
+ BIGNUM *sor = NULL;
+ BIGNUM *eor = NULL;
+ BIGNUM *field = NULL;
+ EC_POINT *R = NULL;
+ EC_POINT *O = NULL;
+ EC_POINT *Q = NULL;
+ BIGNUM *rr = NULL;
+ BIGNUM *zero = NULL;
+ int n = 0;
+ int i = recid / 2;
+
+ const EC_GROUP *group = EC_KEY_get0_group(eckey);
+ if ((ctx = BN_CTX_new()) == NULL) { ret = -1; goto err; }
+ BN_CTX_start(ctx);
+ order = BN_CTX_get(ctx);
+ if (!EC_GROUP_get_order(group, order, ctx)) { ret = -2; goto err; }
+ x = BN_CTX_get(ctx);
+ if (!BN_copy(x, order)) { ret=-1; goto err; }
+ if (!BN_mul_word(x, i)) { ret=-1; goto err; }
+ if (!BN_add(x, x, ecsig->r)) { ret=-1; goto err; }
+ field = BN_CTX_get(ctx);
+ if (!EC_GROUP_get_curve_GFp(group, field, NULL, NULL, ctx)) { ret=-2; goto err; }
+ if (BN_cmp(x, field) >= 0) { ret=0; goto err; }
+ if ((R = EC_POINT_new(group)) == NULL) { ret = -2; goto err; }
+ if (!EC_POINT_set_compressed_coordinates_GFp(group, R, x, recid % 2, ctx)) { ret=0; goto err; }
+ if (check)
+ {
+ if ((O = EC_POINT_new(group)) == NULL) { ret = -2; goto err; }
+ if (!EC_POINT_mul(group, O, NULL, R, order, ctx)) { ret=-2; goto err; }
+ if (!EC_POINT_is_at_infinity(group, O)) { ret = 0; goto err; }
+ }
+ if ((Q = EC_POINT_new(group)) == NULL) { ret = -2; goto err; }
+ n = EC_GROUP_get_degree(group);
+ e = BN_CTX_get(ctx);
+ if (!BN_bin2bn(msg, msglen, e)) { ret=-1; goto err; }
+ if (8*msglen > n) BN_rshift(e, e, 8-(n & 7));
+ zero = BN_CTX_get(ctx);
+ if (!BN_zero(zero)) { ret=-1; goto err; }
+ if (!BN_mod_sub(e, zero, e, order, ctx)) { ret=-1; goto err; }
+ rr = BN_CTX_get(ctx);
+ if (!BN_mod_inverse(rr, ecsig->r, order, ctx)) { ret=-1; goto err; }
+ sor = BN_CTX_get(ctx);
+ if (!BN_mod_mul(sor, ecsig->s, rr, order, ctx)) { ret=-1; goto err; }
+ eor = BN_CTX_get(ctx);
+ if (!BN_mod_mul(eor, e, rr, order, ctx)) { ret=-1; goto err; }
+ if (!EC_POINT_mul(group, Q, eor, R, sor, ctx)) { ret=-2; goto err; }
+ if (!EC_KEY_set_public_key(eckey, Q)) { ret=-2; goto err; }
+
+ ret = 1;
+
+err:
+ if (ctx) {
+ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
+ }
+ if (R != NULL) EC_POINT_free(R);
+ if (O != NULL) EC_POINT_free(O);
+ if (Q != NULL) EC_POINT_free(Q);
+ return ret;
+}