Add GetSecret() and GetKeys() to CKeyStore

[novacoin.git] / src / key.h

diff --git a/src/key.h b/src/key.h
index 3c14cfe..3f4b72d 100644 (file)
--- a/src/key.h
+++ b/src/key.h
@@ -1,13 +1,20 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
+// 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.
 #ifndef BITCOIN_KEY_H
 #define BITCOIN_KEY_H
 
+#include <stdexcept>
+#include <vector>
+
 #include <openssl/ec.h>
 #include <openssl/ecdsa.h>
 #include <openssl/obj_mac.h>
 
+#include "serialize.h"
+#include "uint256.h"
+
 // secp160k1
 // const unsigned int PRIVATE_KEY_SIZE = 192;
 // const unsigned int PUBLIC_KEY_SIZE  = 41;
@@ -31,42 +38,8 @@
 // see www.keylength.com
 // script supports up to 75 for single byte push
 
-int static inline 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);
-}
-
+int extern EC_KEY_regenerate_key(EC_KEY *eckey, BIGNUM *priv_key);
+int extern ECDSA_SIG_recover_key_GFp(EC_KEY *eckey, ECDSA_SIG *ecsig, const unsigned char *msg, int msglen, int recid, int check);
 
 class key_error : public std::runtime_error
 {
@@ -76,7 +49,9 @@ public:
 
 
 // secure_allocator is defined in serialize.h
+// CPrivKey is a serialized private key, with all parameters included (279 bytes)
 typedef std::vector<unsigned char, secure_allocator<unsigned char> > CPrivKey;
+// CSecret is a serialization of just the secret parameter (32 bytes)
 typedef std::vector<unsigned char, secure_allocator<unsigned char> > CSecret;
 
 class CKey
@@ -213,6 +188,72 @@ public:
         return true;
     }
 
+    // create a compact signature (65 bytes), which allows reconstructing the used public key
+    // The format is one header byte, followed by two times 32 bytes for the serialized r and s values.
+    // The header byte: 0x1B = first key with even y, 0x1C = first key with odd y,
+    //                  0x1D = second key with even y, 0x1E = second key with odd y
+    bool SignCompact(uint256 hash, std::vector<unsigned char>& vchSig)
+    {
+        bool fOk = false;
+        ECDSA_SIG *sig = ECDSA_do_sign((unsigned char*)&hash, sizeof(hash), pkey);
+        if (sig==NULL)
+            return false;
+        vchSig.clear();
+        vchSig.resize(65,0);
+        int nBitsR = BN_num_bits(sig->r);
+        int nBitsS = BN_num_bits(sig->s);
+        if (nBitsR <= 256 && nBitsS <= 256)
+        {
+            int nRecId = -1;
+            for (int i=0; i<4; i++)
+            {
+                CKey keyRec;
+                keyRec.fSet = true;
+                if (ECDSA_SIG_recover_key_GFp(keyRec.pkey, sig, (unsigned char*)&hash, sizeof(hash), i, 1) == 1)
+                    if (keyRec.GetPubKey() == this->GetPubKey())
+                    {
+                        nRecId = i;
+                        break;
+                    }
+            }
+
+            if (nRecId == -1)
+                throw key_error("CKey::SignCompact() : unable to construct recoverable key");
+
+            vchSig[0] = nRecId+27;
+            BN_bn2bin(sig->r,&vchSig[33-(nBitsR+7)/8]);
+            BN_bn2bin(sig->s,&vchSig[65-(nBitsS+7)/8]);
+            fOk = true;
+        }
+        ECDSA_SIG_free(sig);
+        return fOk;
+    }
+
+    // reconstruct public key from a compact signature
+    // This is only slightly more CPU intensive than just verifying it.
+    // If this function succeeds, the recovered public key is guaranteed to be valid
+    // (the signature is a valid signature of the given data for that key)
+    bool SetCompactSignature(uint256 hash, const std::vector<unsigned char>& vchSig)
+    {
+        if (vchSig.size() != 65)
+            return false;
+        if (vchSig[0]<27 || vchSig[0]>=31)
+            return false;
+        ECDSA_SIG *sig = ECDSA_SIG_new();
+        BN_bin2bn(&vchSig[1],32,sig->r);
+        BN_bin2bn(&vchSig[33],32,sig->s);
+
+        EC_KEY_free(pkey);
+        pkey = EC_KEY_new_by_curve_name(NID_secp256k1);
+        if (ECDSA_SIG_recover_key_GFp(pkey, sig, (unsigned char*)&hash, sizeof(hash), vchSig[0] - 27, 0) == 1)
+        {
+            fSet = true;
+            ECDSA_SIG_free(sig);
+            return true;
+        }
+        return false;
+    }
+
     bool Verify(uint256 hash, const std::vector<unsigned char>& vchSig)
     {
         // -1 = error, 0 = bad sig, 1 = good
@@ -221,9 +262,15 @@ public:
         return true;
     }
 
-    CBitcoinAddress GetAddress() const
+    // Verify a compact signature
+    bool VerifyCompact(uint256 hash, const std::vector<unsigned char>& vchSig)
     {
-        return CBitcoinAddress(GetPubKey());
+        CKey key;
+        if (!key.SetCompactSignature(hash, vchSig))
+            return false;
+        if (GetPubKey() != key.GetPubKey())
+            return false;
+        return true;
     }
 };