1 files changed, 47 insertions, 11 deletions

diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index adca2142ac..de5ce2ced1 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -10,6 +10,7 @@
 #include <stdint.h>
 #include <string>
 
+class CPubKey;
 class CScript;
 class CTransaction;
 class uint256;
@@ -27,19 +28,54 @@ enum
 enum
 {
     SCRIPT_VERIFY_NONE      = 0,
-    SCRIPT_VERIFY_P2SH      = (1U << 0), // evaluate P2SH (BIP16) subscripts
-    SCRIPT_VERIFY_STRICTENC = (1U << 1), // enforce strict conformance to DER and SEC2 for signatures and pubkeys
-    SCRIPT_VERIFY_LOW_S     = (1U << 2), // enforce low S values (<n/2) in signatures (depends on STRICTENC)
-    SCRIPT_VERIFY_NOCACHE   = (1U << 3), // do not store results in signature cache (but do query it)
-    SCRIPT_VERIFY_NULLDUMMY = (1U << 4), // verify dummy stack item consumed by CHECKMULTISIG is of zero-length
-};
 
-bool IsCanonicalPubKey(const std::vector<unsigned char> &vchPubKey, unsigned int flags);
-bool IsCanonicalSignature(const std::vector<unsigned char> &vchSig, unsigned int flags);
+    // Evaluate P2SH subscripts (softfork safe, BIP16).
+    SCRIPT_VERIFY_P2SH      = (1U << 0),
+
+    // Passing a non-strict-DER signature or one with undefined hashtype to a checksig operation causes script failure.
+    // Passing a pubkey that is not (0x04 + 64 bytes) or (0x02 or 0x03 + 32 bytes) to checksig causes that pubkey to be
+    // skipped (not softfork safe: this flag can widen the validity of OP_CHECKSIG OP_NOT).
+    SCRIPT_VERIFY_STRICTENC = (1U << 1),
+
+    // Passing a non-strict-DER signature to a checksig operation causes script failure (softfork safe, BIP62 rule 1)
+    SCRIPT_VERIFY_DERSIG    = (1U << 2),
+
+    // Passing a non-strict-DER signature or one with S > order/2 to a checksig operation causes script failure
+    // (softfork safe, BIP62 rule 5).
+    SCRIPT_VERIFY_LOW_S     = (1U << 3),
+
+    // verify dummy stack item consumed by CHECKMULTISIG is of zero-length (softfork safe, BIP62 rule 7).
+    SCRIPT_VERIFY_NULLDUMMY = (1U << 4),
+};
 
 uint256 SignatureHash(const CScript &scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType);
-bool CheckSig(std::vector<unsigned char> vchSig, const std::vector<unsigned char> &vchPubKey, const CScript &scriptCode, const CTransaction& txTo, unsigned int nIn, int flags);
-bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, const CTransaction& txTo, unsigned int nIn, unsigned int flags);
-bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CTransaction& txTo, unsigned int nIn, unsigned int flags);
+
+class BaseSignatureChecker
+{
+public:
+    virtual bool CheckSig(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode) const
+    {
+        return false;
+    }
+
+    virtual ~BaseSignatureChecker() {}
+};
+
+class SignatureChecker : public BaseSignatureChecker
+{
+private:
+    const CTransaction& txTo;
+    unsigned int nIn;
+
+protected:
+    virtual bool VerifySignature(const std::vector<unsigned char>& vchSig, const CPubKey& vchPubKey, const uint256& sighash) const;
+
+public:
+    SignatureChecker(const CTransaction& txToIn, unsigned int nInIn) : txTo(txToIn), nIn(nInIn) {}
+    bool CheckSig(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode) const;
+};
+
+bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker);
+bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigned int flags, const BaseSignatureChecker& checker);
 
 #endif // H_BITCOIN_SCRIPT_INTERPRETER