Update copyrights to 2012 for files modified this year

[novacoin.git] / src / key.h

diff --git a/src/key.h b/src/key.h
index 5ffd7b9..6da0dc2 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
@@ -292,6 +298,9 @@ public:
     }
 
     // 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 +327,7 @@ 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]);
@@ -330,6 +339,9 @@ 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)
@@ -359,6 +371,7 @@ public:
         return true;
     }
 
+    // Verify a compact signature
     bool VerifyCompact(uint256 hash, const std::vector<unsigned char>& vchSig)
     {
         CKey key;
@@ -369,10 +382,22 @@ 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