Pharao Release

Version 4.0.0.4
- refactored code
- migrated vom Qt4 to Qt5
- added secure messaging

src/key.cpp

@@ -126,6 +126,17 @@ void CKey::SetCompressedPubKey()
     fCompressedPubKey = true;
 }
 
+void CKey::SetUnCompressedPubKey()
+{
+    EC_KEY_set_conv_form(pkey, POINT_CONVERSION_UNCOMPRESSED);
+    fCompressedPubKey = false;
+}
+
+EC_KEY* CKey::GetECKey()
+{
+    return pkey;
+}
+
 void CKey::Reset()
 {
     fCompressedPubKey = false;
@@ -174,6 +185,54 @@ bool CKey::IsCompressed() const
     return fCompressedPubKey;
 }
 
+int CompareBigEndian(const unsigned char *c1, size_t c1len, const unsigned char *c2, size_t c2len) {
+    while (c1len > c2len) {
+        if (*c1)
+            return 1;
+        c1++;
+        c1len--;
+    }
+    while (c2len > c1len) {
+        if (*c2)
+            return -1;
+        c2++;
+        c2len--;
+    }
+    while (c1len > 0) {
+        if (*c1 > *c2)
+            return 1;
+        if (*c2 > *c1)
+            return -1;
+        c1++;
+        c2++;
+        c1len--;
+    }
+    return 0;
+}
+
+// Order of secp256k1's generator minus 1.
+const unsigned char vchMaxModOrder[32] = {
+    0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
+    0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFE,
+    0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,
+    0xBF,0xD2,0x5E,0x8C,0xD0,0x36,0x41,0x40
+};
+
+// Half of the order of secp256k1's generator minus 1.
+const unsigned char vchMaxModHalfOrder[32] = {
+    0x7F,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
+    0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
+    0x5D,0x57,0x6E,0x73,0x57,0xA4,0x50,0x1D,
+    0xDF,0xE9,0x2F,0x46,0x68,0x1B,0x20,0xA0
+};
+
+const unsigned char vchZero[0] = {};
+
+bool CKey::CheckSignatureElement(const unsigned char *vch, int len, bool half) {
+    return CompareBigEndian(vch, len, vchZero, 0) > 0 &&
+           CompareBigEndian(vch, len, half ? vchMaxModHalfOrder : vchMaxModOrder, 32) <= 0;
+}
+
 void CKey::MakeNewKey(bool fCompressed)
 {
     if (!EC_KEY_generate_key(pkey))
@@ -285,13 +344,28 @@ CPubKey CKey::GetPubKey() const
 
 bool CKey::Sign(uint256 hash, std::vector<unsigned char>& vchSig)
 {
+    vchSig.clear();
+    ECDSA_SIG *sig = ECDSA_do_sign((unsigned char*)&hash, sizeof(hash), pkey);
+    if (sig == NULL)
+        return false;
+    BN_CTX *ctx = BN_CTX_new();
+    BN_CTX_start(ctx);
+    const EC_GROUP *group = EC_KEY_get0_group(pkey);
+    BIGNUM *order = BN_CTX_get(ctx);
+    BIGNUM *halforder = BN_CTX_get(ctx);
+    EC_GROUP_get_order(group, order, ctx);
+    BN_rshift1(halforder, order);
+    if (BN_cmp(sig->s, halforder) > 0) {
+        // enforce low S values, by negating the value (modulo the order) if above order/2.
+        BN_sub(sig->s, order, sig->s);
+    }
+    BN_CTX_end(ctx);
+    BN_CTX_free(ctx);
     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;
-    }
+    unsigned char *pos = &vchSig[0];
+    nSize = i2d_ECDSA_SIG(sig, &pos);
+    ECDSA_SIG_free(sig);
     vchSig.resize(nSize); // Shrink to fit actual size
     return true;
 }
@@ -328,7 +402,10 @@ bool CKey::SignCompact(uint256 hash, std::vector<unsigned char>& vchSig)
         }
 
         if (nRecId == -1)
+        {
+            ECDSA_SIG_free(sig);
             throw key_error("CKey::SignCompact() : unable to construct recoverable key");
+        }
 
         vchSig[0] = nRecId+27+(fCompressedPubKey ? 4 : 0);
         BN_bn2bin(sig->r,&vchSig[33-(nBitsR+7)/8]);
@@ -367,6 +444,7 @@ bool CKey::SetCompactSignature(uint256 hash, const std::vector<unsigned char>& v
         ECDSA_SIG_free(sig);
         return true;
     }
+    ECDSA_SIG_free(sig);
     return false;
 }
 
@@ -404,3 +482,13 @@ bool CKey::IsValid()
     key2.SetSecret(secret, fCompr);
     return GetPubKey() == key2.GetPubKey();
 }
+
+bool ECC_InitSanityCheck() {
+    EC_KEY *pkey = EC_KEY_new_by_curve_name(NID_secp256k1);
+    if(pkey == NULL)
+        return false;
+    EC_KEY_free(pkey);
+
+    // TODO Is there more EC functionality that could be missing?
+    return true;
+}