Use a messagebox to display the error when -server is provided without providing...

[novacoin.git] / src / key.h

diff --git a/src/key.h b/src/key.h
index 5ffd7b9..8c06a45 100644 (file)
--- a/src/key.h
+++ b/src/key.h
@@ -1,5 +1,5 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2011 The Bitcoin developers
+// Copyright (c) 2009-2012 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
@@ -39,6 +39,7 @@
 // see www.keylength.com
 // script supports up to 75 for single byte push
 
+// Generate a private key from just the secret parameter
 int static inline EC_KEY_regenerate_key(EC_KEY *eckey, BIGNUM *priv_key)
 {
     int ok = 0;
@@ -75,6 +76,9 @@ err:
     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 static inline 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;
@@ -154,7 +158,9 @@ 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
@@ -163,6 +169,11 @@ protected:
     EC_KEY* pkey;
     bool fSet;
 
+    void SetCompressedPubKey()
+    {
+        EC_KEY_set_conv_form(pkey, POINT_CONVERSION_COMPRESSED);
+    }
+
 public:
     CKey()
     {
@@ -223,10 +234,13 @@ public:
         if (vchSecret.size() != 32)
             throw key_error("CKey::SetSecret() : secret must be 32 bytes");
         BIGNUM *bn = BN_bin2bn(&vchSecret[0],32,BN_new());
-        if (bn == NULL) 
+        if (bn == NULL)
             throw key_error("CKey::SetSecret() : BN_bin2bn failed");
         if (!EC_KEY_regenerate_key(pkey,bn))
+        {
+            BN_clear_free(bn);
             throw key_error("CKey::SetSecret() : EC_KEY_regenerate_key failed");
+        }
         BN_clear_free(bn);
         fSet = true;
         return true;
@@ -281,17 +295,21 @@ public:
 
     bool Sign(uint256 hash, std::vector<unsigned char>& vchSig)
     {
-        vchSig.clear();
-        unsigned char pchSig[10000];
-        unsigned int nSize = 0;
-        if (!ECDSA_sign(0, (unsigned char*)&hash, sizeof(hash), pchSig, &nSize, pkey))
+        unsigned int nSize = ECDSA_size(pkey);
+        vchSig.resize(nSize); // Make sure it is big enough
+        if (!ECDSA_sign(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], &nSize, pkey))
+        {
+            vchSig.clear();
             return false;
-        vchSig.resize(nSize);
-        memcpy(&vchSig[0], pchSig, nSize);
+        }
+        vchSig.resize(nSize); // Shrink to fit actual size
         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;
@@ -318,7 +336,7 @@ public:
             }
 
             if (nRecId == -1)
-                throw key_error("CKEy::SignCompact() : unable to construct recoverable key");
+                throw key_error("CKey::SignCompact() : unable to construct recoverable key");
 
             vchSig[0] = nRecId+27;
             BN_bn2bin(sig->r,&vchSig[33-(nBitsR+7)/8]);
@@ -330,11 +348,15 @@ public:
     }
 
     // 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)
+        int nV = vchSig[0];
+        if (nV<27 || nV>=35)
             return false;
         ECDSA_SIG *sig = ECDSA_SIG_new();
         BN_bin2bn(&vchSig[1],32,sig->r);
@@ -342,7 +364,12 @@ public:
 
         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)
+        if (nV >= 31)
+        {
+            SetCompressedPubKey();
+            nV -= 4;
+        }
+        if (ECDSA_SIG_recover_key_GFp(pkey, sig, (unsigned char*)&hash, sizeof(hash), nV - 27, 0) == 1)
         {
             fSet = true;
             ECDSA_SIG_free(sig);
@@ -359,6 +386,7 @@ public:
         return true;
     }
 
+    // Verify a compact signature
     bool VerifyCompact(uint256 hash, const std::vector<unsigned char>& vchSig)
     {
         CKey key;
@@ -369,10 +397,22 @@ public:
         return true;
     }
 
+    // Get the address corresponding to this key
     CBitcoinAddress GetAddress() const
     {
         return CBitcoinAddress(GetPubKey());
     }
+
+    bool IsValid()
+    {
+        if (!fSet)
+            return false;
+
+        CSecret secret = GetSecret();
+        CKey key2;
+        key2.SetSecret(secret);
+        return GetPubKey() == key2.GetPubKey();
+    }
 };
 
 #endif