Merge pull request #5714

3916a81 Increase coverage of DERSIG edge cases (Pieter Wuille)
6da2028 Add RPC test for DERSIG BIP switchover logic (Pieter Wuille)
773c30d BIP66 changeover logic (Pieter Wuille)
18695f0 Example unit tests from BIP66 (Pieter Wuille)
abfbeaf Change IsDERSignature to BIP66 implementation (Pieter Wuille)

9 files changed, 405 insertions, 64 deletions

diff --git a/qa/rpc-tests/bipdersig.py b/qa/rpc-tests/bipdersig.py
new file mode 100755
index 0000000000..9f2cc84601
--- /dev/null
+++ b/qa/rpc-tests/bipdersig.py
@@ -0,0 +1,90 @@
+#!/usr/bin/env python2
+# Copyright (c) 2014 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#
+# Test the BIP66 changeover logic
+#
+
+from test_framework import BitcoinTestFramework
+from bitcoinrpc.authproxy import AuthServiceProxy, JSONRPCException
+from util import *
+import os
+import shutil
+
+class BIP66Test(BitcoinTestFramework):
+
+    def setup_network(self):
+        self.nodes = []
+        self.nodes.append(start_node(0, self.options.tmpdir, []))
+        self.nodes.append(start_node(1, self.options.tmpdir, ["-blockversion=2"]))
+        self.nodes.append(start_node(2, self.options.tmpdir, ["-blockversion=3"]))
+        connect_nodes(self.nodes[1], 0)
+        connect_nodes(self.nodes[2], 0)
+        self.is_network_split = False
+        self.sync_all()
+
+    def run_test(self):
+        cnt = self.nodes[0].getblockcount()
+
+        # Mine some old-version blocks
+        self.nodes[1].setgenerate(True, 100)
+        self.sync_all()
+        if (self.nodes[0].getblockcount() != cnt + 100):
+            raise AssertionError("Failed to mine 100 version=2 blocks")
+
+        # Mine 750 new-version blocks
+        for i in xrange(15):
+            self.nodes[2].setgenerate(True, 50)
+        self.sync_all()
+        if (self.nodes[0].getblockcount() != cnt + 850):
+            raise AssertionError("Failed to mine 750 version=3 blocks")
+
+        # TODO: check that new DERSIG rules are not enforced
+
+        # Mine 1 new-version block
+        self.nodes[2].setgenerate(True, 1)
+        self.sync_all()
+        if (self.nodes[0].getblockcount() != cnt + 851):
+            raise AssertionFailure("Failed to mine a version=3 blocks")
+
+        # TODO: check that new DERSIG rules are enforced
+
+        # Mine 198 new-version blocks
+        for i in xrange(2):
+            self.nodes[2].setgenerate(True, 99)
+        self.sync_all()
+        if (self.nodes[0].getblockcount() != cnt + 1049):
+            raise AssertionError("Failed to mine 198 version=3 blocks")
+
+        # Mine 1 old-version block
+        self.nodes[1].setgenerate(True, 1)
+        self.sync_all()
+        if (self.nodes[0].getblockcount() != cnt + 1050):
+            raise AssertionError("Failed to mine a version=2 block after 949 version=3 blocks")
+
+        # Mine 1 new-version blocks
+        self.nodes[2].setgenerate(True, 1)
+        self.sync_all()
+        if (self.nodes[0].getblockcount() != cnt + 1051):
+            raise AssertionError("Failed to mine a version=3 block")
+
+        # Mine 1 old-version blocks
+        try:
+            self.nodes[1].setgenerate(True, 1)
+            raise AssertionError("Succeeded to mine a version=2 block after 950 version=3 blocks")
+        except JSONRPCException:
+            pass
+        self.sync_all()
+        if (self.nodes[0].getblockcount() != cnt + 1051):
+            raise AssertionError("Accepted a version=2 block after 950 version=3 blocks")
+
+        # Mine 1 new-version blocks
+        self.nodes[2].setgenerate(True, 1)
+        self.sync_all()
+        if (self.nodes[0].getblockcount() != cnt + 1052):
+            raise AssertionError("Failed to mine a version=3 block")
+
+if __name__ == '__main__':
+    BIP66Test().main()
diff --git a/src/main.cpp b/src/main.cpp
index 09b0ac7af9..a7d9391cd9 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1685,6 +1685,11 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
 
     unsigned int flags = fStrictPayToScriptHash ? SCRIPT_VERIFY_P2SH : SCRIPT_VERIFY_NONE;
 
+    // Start enforcing the DERSIG (BIP66) rules, for block.nVersion=3 blocks, when 75% of the network has upgraded:
+    if (block.nVersion >= 3 && CBlockIndex::IsSuperMajority(3, pindex->pprev, Params().EnforceBlockUpgradeMajority())) {
+        flags |= SCRIPT_VERIFY_DERSIG;
+    }
+
     CBlockUndo blockundo;
 
     CCheckQueueControl<CScriptCheck> control(fScriptChecks && nScriptCheckThreads ? &scriptcheckqueue : NULL);
@@ -2524,6 +2529,13 @@ bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& sta
                              REJECT_OBSOLETE, "bad-version");
     }
 
+    // Reject block.nVersion=2 blocks when 95% (75% on testnet) of the network has upgraded:
+    if (block.nVersion < 3 && CBlockIndex::IsSuperMajority(3, pindexPrev, Params().RejectBlockOutdatedMajority()))
+    {
+        return state.Invalid(error("%s : rejected nVersion=2 block", __func__),
+                             REJECT_OBSOLETE, "bad-version");
+    }
+
     return true;
 }
 
diff --git a/src/primitives/block.h b/src/primitives/block.h
index a189592539..9c17902e15 100644
--- a/src/primitives/block.h
+++ b/src/primitives/block.h
@@ -24,7 +24,7 @@ class CBlockHeader
 {
 public:
     // header
-    static const int32_t CURRENT_VERSION=2;
+    static const int32_t CURRENT_VERSION=3;
     int32_t nVersion;
     uint256 hashPrevBlock;
     uint256 hashMerkleRoot;
diff --git a/src/script/bitcoinconsensus.h b/src/script/bitcoinconsensus.h
index 15e3337a8d..c57d8b3cc5 100644
--- a/src/script/bitcoinconsensus.h
+++ b/src/script/bitcoinconsensus.h
@@ -46,6 +46,7 @@ enum
 {
     bitcoinconsensus_SCRIPT_FLAGS_VERIFY_NONE      = 0,
     bitcoinconsensus_SCRIPT_FLAGS_VERIFY_P2SH      = (1U << 0), // evaluate P2SH (BIP16) subscripts
+    bitcoinconsensus_SCRIPT_FLAGS_VERIFY_DERSIG    = (1U << 2), // enforce strict DER (BIP66) compliance
 };
 
 /// Returns 1 if the input nIn of the serialized transaction pointed to by
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index 41a0e1c490..555a16a243 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -93,76 +93,76 @@ bool static IsCompressedOrUncompressedPubKey(const valtype &vchPubKey) {
  * in which case a single 0 byte is necessary and even required).
  * 
  * See https://bitcointalk.org/index.php?topic=8392.msg127623#msg127623
+ *
+ * This function is consensus-critical since BIP66.
  */
-bool static IsDERSignature(const valtype &vchSig) {
+bool static IsValidSignatureEncoding(const std::vector<unsigned char> &sig) {
+    // Format: 0x30 [total-length] 0x02 [R-length] [R] 0x02 [S-length] [S] [sighash]
+    // * total-length: 1-byte length descriptor of everything that follows,
+    //   excluding the sighash byte.
+    // * R-length: 1-byte length descriptor of the R value that follows.
+    // * R: arbitrary-length big-endian encoded R value. It must use the shortest
+    //   possible encoding for a positive integers (which means no null bytes at
+    //   the start, except a single one when the next byte has its highest bit set).
+    // * S-length: 1-byte length descriptor of the S value that follows.
+    // * S: arbitrary-length big-endian encoded S value. The same rules apply.
+    // * sighash: 1-byte value indicating what data is hashed (not part of the DER
+    //   signature)
 
-    if (vchSig.size() < 9) {
-        //  Non-canonical signature: too short
-        return false;
-    }
-    if (vchSig.size() > 73) {
-        // Non-canonical signature: too long
-        return false;
-    }
-    if (vchSig[0] != 0x30) {
-        //  Non-canonical signature: wrong type
-        return false;
-    }
-    if (vchSig[1] != vchSig.size()-3) {
-        //  Non-canonical signature: wrong length marker
-        return false;
-    }
-    unsigned int nLenR = vchSig[3];
-    if (5 + nLenR >= vchSig.size()) {
-        //  Non-canonical signature: S length misplaced
-        return false;
-    }
-    unsigned int nLenS = vchSig[5+nLenR];
-    if ((unsigned long)(nLenR+nLenS+7) != vchSig.size()) {
-        //  Non-canonical signature: R+S length mismatch
-        return false;
-    }
+    // Minimum and maximum size constraints.
+    if (sig.size() < 9) return false;
+    if (sig.size() > 73) return false;
 
-    const unsigned char *R = &vchSig[4];
-    if (R[-2] != 0x02) {
-        //  Non-canonical signature: R value type mismatch
-        return false;
-    }
-    if (nLenR == 0) {
-        //  Non-canonical signature: R length is zero
-        return false;
-    }
-    if (R[0] & 0x80) {
-        //  Non-canonical signature: R value negative
-        return false;
-    }
-    if (nLenR > 1 && (R[0] == 0x00) && !(R[1] & 0x80)) {
-        //  Non-canonical signature: R value excessively padded
-        return false;
-    }
+    // A signature is of type 0x30 (compound).
+    if (sig[0] != 0x30) return false;
+
+    // Make sure the length covers the entire signature.
+    if (sig[1] != sig.size() - 3) return false;
+
+    // Extract the length of the R element.
+    unsigned int lenR = sig[3];
+
+    // Make sure the length of the S element is still inside the signature.
+    if (5 + lenR >= sig.size()) return false;
+
+    // Extract the length of the S element.
+    unsigned int lenS = sig[5 + lenR];
+
+    // Verify that the length of the signature matches the sum of the length
+    // of the elements.
+    if ((size_t)(lenR + lenS + 7) != sig.size()) return false;
+ 
+    // Check whether the R element is an integer.
+    if (sig[2] != 0x02) return false;
+
+    // Zero-length integers are not allowed for R.
+    if (lenR == 0) return false;
+
+    // Negative numbers are not allowed for R.
+    if (sig[4] & 0x80) return false;
+
+    // Null bytes at the start of R are not allowed, unless R would
+    // otherwise be interpreted as a negative number.
+    if (lenR > 1 && (sig[4] == 0x00) && !(sig[5] & 0x80)) return false;
+
+    // Check whether the S element is an integer.
+    if (sig[lenR + 4] != 0x02) return false;
+
+    // Zero-length integers are not allowed for S.
+    if (lenS == 0) return false;
+
+    // Negative numbers are not allowed for S.
+    if (sig[lenR + 6] & 0x80) return false;
+
+    // Null bytes at the start of S are not allowed, unless S would otherwise be
+    // interpreted as a negative number.
+    if (lenS > 1 && (sig[lenR + 6] == 0x00) && !(sig[lenR + 7] & 0x80)) return false;
 
-    const unsigned char *S = &vchSig[6+nLenR];
-    if (S[-2] != 0x02) {
-        //  Non-canonical signature: S value type mismatch
-        return false;
-    }
-    if (nLenS == 0) {
-        //  Non-canonical signature: S length is zero
-        return false;
-    }
-    if (S[0] & 0x80) {
-        //  Non-canonical signature: S value negative
-        return false;
-    }
-    if (nLenS > 1 && (S[0] == 0x00) && !(S[1] & 0x80)) {
-        //  Non-canonical signature: S value excessively padded
-        return false;
-    }
     return true;
 }
 
 bool static IsLowDERSignature(const valtype &vchSig, ScriptError* serror) {
-    if (!IsDERSignature(vchSig)) {
+    if (!IsValidSignatureEncoding(vchSig)) {
         return set_error(serror, SCRIPT_ERR_SIG_DER);
     }
     unsigned int nLenR = vchSig[3];
@@ -194,7 +194,7 @@ bool static CheckSignatureEncoding(const valtype &vchSig, unsigned int flags, Sc
     if (vchSig.size() == 0) {
         return true;
     }
-    if ((flags & (SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_STRICTENC)) != 0 && !IsDERSignature(vchSig)) {
+    if ((flags & (SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_STRICTENC)) != 0 && !IsValidSignatureEncoding(vchSig)) {
         return set_error(serror, SCRIPT_ERR_SIG_DER);
     } else if ((flags & SCRIPT_VERIFY_LOW_S) != 0 && !IsLowDERSignature(vchSig, serror)) {
         // serror is set
diff --git a/src/script/standard.h b/src/script/standard.h
index c4b82b4c45..3fea6b9ab9 100644
--- a/src/script/standard.h
+++ b/src/script/standard.h
@@ -45,6 +45,7 @@ static const unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH;
  * blocks and we must accept those blocks.
  */
 static const unsigned int STANDARD_SCRIPT_VERIFY_FLAGS = MANDATORY_SCRIPT_VERIFY_FLAGS |
+                                                         SCRIPT_VERIFY_DERSIG |
                                                          SCRIPT_VERIFY_STRICTENC |
                                                          SCRIPT_VERIFY_MINIMALDATA |
                                                          SCRIPT_VERIFY_NULLDUMMY |
diff --git a/src/test/data/script_invalid.json b/src/test/data/script_invalid.json
index 09120e8838..e63018051d 100644
--- a/src/test/data/script_invalid.json
+++ b/src/test/data/script_invalid.json
@@ -510,6 +510,16 @@
     "2-of-2 CHECKMULTISIG NOT with both pubkeys valid, but first signature invalid."
 ],
 
+["Increase DERSIG test coverage"],
+["0x4a 0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", "0 CHECKSIG NOT", "DERSIG", "Overly long signature is incorrectly encoded for DERSIG"],
+["0x25 0x30220220000000000000000000000000000000000000000000000000000000000000000000", "0 CHECKSIG NOT", "DERSIG", "Missing S is incorrectly encoded for DERSIG"],
+["0x27 0x3024021077777777777777777777777777777777020a7777777777777777777777777777777701", "0 CHECKSIG NOT", "DERSIG", "S with invalid S length is incorrectly encoded for DERSIG"],
+["0x27 0x302403107777777777777777777777777777777702107777777777777777777777777777777701", "0 CHECKSIG NOT", "DERSIG", "Non-integer R is incorrectly encoded for DERSIG"],
+["0x27 0x302402107777777777777777777777777777777703107777777777777777777777777777777701", "0 CHECKSIG NOT", "DERSIG", "Non-integer S is incorrectly encoded for DERSIG"],
+["0x17 0x3014020002107777777777777777777777777777777701", "0 CHECKSIG NOT", "DERSIG", "Zero-length R is incorrectly encoded for DERSIG"],
+["0x17 0x3014021077777777777777777777777777777777020001", "0 CHECKSIG NOT", "DERSIG", "Zero-length S is incorrectly encoded for DERSIG"],
+["0x27 0x302402107777777777777777777777777777777702108777777777777777777777777777777701", "0 CHECKSIG NOT", "DERSIG", "Negative S is incorrectly encoded for DERSIG"],
+
 ["Automatically generated test cases"],
 [
     "0x47 0x3044022053205076a7bb12d2db3162a2d97d8197631f829b065948b7019b15482af819a902204328dcc02c994ca086b1226d0d5f1674d23cfae0d846143df812b81cab3391e801",
@@ -590,6 +600,102 @@
     "P2PK NOT with too much R padding"
 ],
 [
+    "0x47 0x30440220d7a0417c3f6d1a15094d1cf2a3378ca0503eb8a57630953a9e2987e21ddd0a6502207a6266d686c99090920249991d3d42065b6d43eb70187b219c0db82e4f94d1a201",
+    "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG",
+    "DERSIG",
+    "BIP66 example 1, with DERSIG"
+],
+[
+    "0x47 0x304402208e43c0b91f7c1e5bc58e41c8185f8a6086e111b0090187968a86f2822462d3c902200a58f4076b1133b18ff1dc83ee51676e44c60cc608d9534e0df5ace0424fc0be01",
+    "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG NOT",
+    "",
+    "BIP66 example 2, without DERSIG"
+],
+[
+    "0x47 0x304402208e43c0b91f7c1e5bc58e41c8185f8a6086e111b0090187968a86f2822462d3c902200a58f4076b1133b18ff1dc83ee51676e44c60cc608d9534e0df5ace0424fc0be01",
+    "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG NOT",
+    "DERSIG",
+    "BIP66 example 2, with DERSIG"
+],
+[
+    "0",
+    "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG",
+    "",
+    "BIP66 example 3, without DERSIG"
+],
+[
+    "0",
+    "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG",
+    "DERSIG",
+    "BIP66 example 3, with DERSIG"
+],
+[
+    "1",
+    "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG",
+    "",
+    "BIP66 example 5, without DERSIG"
+],
+[
+    "1",
+    "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG",
+    "DERSIG",
+    "BIP66 example 5, with DERSIG"
+],
+[
+    "1",
+    "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG NOT",
+    "DERSIG",
+    "BIP66 example 6, with DERSIG"
+],
+[
+    "0 0x47 0x30440220cae00b1444babfbf6071b0ba8707f6bd373da3df494d6e74119b0430c5db810502205d5231b8c5939c8ff0c82242656d6e06edb073d42af336c99fe8837c36ea39d501 0x47 0x304402200b3d0b0375bb15c14620afa4aa10ae90a0d6a046ce217bc20fe0bc1ced68c1b802204b550acab90ae6d3478057c9ad24f9df743815b799b6449dd7e7f6d3bc6e274c01",
+    "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG",
+    "DERSIG",
+    "BIP66 example 7, with DERSIG"
+],
+[
+    "0 0x47 0x30440220f00a77260d34ec2f0c59621dc710f58169d0ca06df1a88cd4b1f1b97bd46991b02201ee220c7e04f26aed03f94aa97fb09ca5627163bf4ba07e6979972ec737db22601 0x47 0x3044022079ea80afd538d9ada421b5101febeb6bc874e01dde5bca108c1d0479aec339a4022004576db8f66130d1df686ccf00935703689d69cf539438da1edab208b0d63c4801",
+    "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG NOT",
+    "",
+    "BIP66 example 8, without DERSIG"
+],
+[
+    "0 0x47 0x30440220f00a77260d34ec2f0c59621dc710f58169d0ca06df1a88cd4b1f1b97bd46991b02201ee220c7e04f26aed03f94aa97fb09ca5627163bf4ba07e6979972ec737db22601 0x47 0x3044022079ea80afd538d9ada421b5101febeb6bc874e01dde5bca108c1d0479aec339a4022004576db8f66130d1df686ccf00935703689d69cf539438da1edab208b0d63c4801",
+    "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG NOT",
+    "DERSIG",
+    "BIP66 example 8, with DERSIG"
+],
+[
+    "0 0 0x47 0x3044022081aa9d436f2154e8b6d600516db03d78de71df685b585a9807ead4210bd883490220534bb6bdf318a419ac0749660b60e78d17d515558ef369bf872eff405b676b2e01",
+    "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG",
+    "",
+    "BIP66 example 9, without DERSIG"
+],
+[
+    "0 0 0x47 0x3044022081aa9d436f2154e8b6d600516db03d78de71df685b585a9807ead4210bd883490220534bb6bdf318a419ac0749660b60e78d17d515558ef369bf872eff405b676b2e01",
+    "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG",
+    "DERSIG",
+    "BIP66 example 9, with DERSIG"
+],
+[
+    "0 0 0x47 0x30440220afa76a8f60622f813b05711f051c6c3407e32d1b1b70b0576c1f01b54e4c05c702200d58e9df044fd1845cabfbeef6e624ba0401daf7d7e084736f9ff601c3783bf501",
+    "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG NOT",
+    "DERSIG",
+    "BIP66 example 10, with DERSIG"
+],
+[
+    "0 0x47 0x30440220cae00b1444babfbf6071b0ba8707f6bd373da3df494d6e74119b0430c5db810502205d5231b8c5939c8ff0c82242656d6e06edb073d42af336c99fe8837c36ea39d501 0",
+    "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG",
+    "",
+    "BIP66 example 11, without DERSIG"
+],
+[
+    "0 0x47 0x30440220cae00b1444babfbf6071b0ba8707f6bd373da3df494d6e74119b0430c5db810502205d5231b8c5939c8ff0c82242656d6e06edb073d42af336c99fe8837c36ea39d501 0",
+    "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG",
+    "DERSIG",
+    "BIP66 example 11, with DERSIG"
+],
+[
     "0x49 0x304502203e4516da7253cf068effec6b95c41221c0cf3a8e6ccb8cbf1725b562e9afde2c022100ab1e3da73d67e32045a20e0b999e049978ea8d6ee5480d485fcf2ce0d03b2ef05101",
     "0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 CHECKSIG",
     "LOW_S",
diff --git a/src/test/data/script_valid.json b/src/test/data/script_valid.json
index 17398ca1bd..42e9edbd37 100644
--- a/src/test/data/script_valid.json
+++ b/src/test/data/script_valid.json
@@ -688,6 +688,16 @@
     "2-of-2 CHECKMULTISIG NOT with both pubkeys valid, but second signature invalid. Valid pubkey fails, and CHECKMULTISIG exits early, prior to evaluation of second invalid signature."
 ],
 
+["Increase test coverage for DERSIG"],
+["0x4a 0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", "0 CHECKSIG NOT", "", "Overly long signature is correctly encoded"],
+["0x25 0x30220220000000000000000000000000000000000000000000000000000000000000000000", "0 CHECKSIG NOT", "", "Missing S is correctly encoded"],
+["0x27 0x3024021077777777777777777777777777777777020a7777777777777777777777777777777701", "0 CHECKSIG NOT", "", "S with invalid S length is correctly encoded"],
+["0x27 0x302403107777777777777777777777777777777702107777777777777777777777777777777701", "0 CHECKSIG NOT", "", "Non-integer R is correctly encoded"],
+["0x27 0x302402107777777777777777777777777777777703107777777777777777777777777777777701", "0 CHECKSIG NOT", "", "Non-integer S is correctly encoded"],
+["0x17 0x3014020002107777777777777777777777777777777701", "0 CHECKSIG NOT", "", "Zero-length R is correctly encoded"],
+["0x17 0x3014021077777777777777777777777777777777020001", "0 CHECKSIG NOT", "", "Zero-length S is correctly encoded for DERSIG"],
+["0x27 0x302402107777777777777777777777777777777702108777777777777777777777777777777701", "0 CHECKSIG NOT", "", "Negative S is correctly encoded"],
+
 ["Automatically generated test cases"],
 [
     "0x47 0x3044022053205076a7bb13d2db3162a2d97d8197631f829b065948b7019b15482af819a902204328dcc02c994ca086b1226d0d5f1674d23cfae0d846143df812b81cab3391e801",
@@ -756,6 +766,54 @@
     "P2PK NOT with bad sig with too much R padding but no DERSIG"
 ],
 [
+    "0x47 0x30440220d7a0417c3f6d1a15094d1cf2a3378ca0503eb8a57630953a9e2987e21ddd0a6502207a6266d686c99090920249991d3d42065b6d43eb70187b219c0db82e4f94d1a201",
+    "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG",
+    "",
+    "BIP66 example 1, without DERSIG"
+],
+[
+    "0",
+    "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG NOT",
+    "",
+    "BIP66 example 4, without DERSIG"
+],
+[
+    "0",
+    "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG NOT",
+    "DERSIG",
+    "BIP66 example 4, with DERSIG"
+],
+[
+    "1",
+    "0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 CHECKSIG NOT",
+    "",
+    "BIP66 example 6, without DERSIG"
+],
+[
+    "0 0x47 0x30440220cae00b1444babfbf6071b0ba8707f6bd373da3df494d6e74119b0430c5db810502205d5231b8c5939c8ff0c82242656d6e06edb073d42af336c99fe8837c36ea39d501 0x47 0x304402200b3d0b0375bb15c14620afa4aa10ae90a0d6a046ce217bc20fe0bc1ced68c1b802204b550acab90ae6d3478057c9ad24f9df743815b799b6449dd7e7f6d3bc6e274c01",
+    "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG",
+    "",
+    "BIP66 example 7, without DERSIG"
+],
+[
+    "0 0 0x47 0x30440220afa76a8f60622f813b05711f051c6c3407e32d1b1b70b0576c1f01b54e4c05c702200d58e9df044fd1845cabfbeef6e624ba0401daf7d7e084736f9ff601c3783bf501",
+    "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG NOT",
+    "",
+    "BIP66 example 10, without DERSIG"
+],
+[
+    "0 0x47 0x30440220f00a77260d34ec2f0c59621dc710f58169d0ca06df1a88cd4b1f1b97bd46991b02201ee220c7e04f26aed03f94aa97fb09ca5627163bf4ba07e6979972ec737db22601 0",
+    "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG NOT",
+    "",
+    "BIP66 example 12, without DERSIG"
+],
+[
+    "0 0x47 0x30440220f00a77260d34ec2f0c59621dc710f58169d0ca06df1a88cd4b1f1b97bd46991b02201ee220c7e04f26aed03f94aa97fb09ca5627163bf4ba07e6979972ec737db22601 0",
+    "2 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 2 CHECKMULTISIG NOT",
+    "DERSIG",
+    "BIP66 example 12, with DERSIG"
+],
+[
     "0x49 0x304502203e4516da7253cf068effec6b95c41221c0cf3a8e6ccb8cbf1725b562e9afde2c022100ab1e3da73d67e32045a20e0b999e049978ea8d6ee5480d485fcf2ce0d03b2ef05101",
     "0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 CHECKSIG",
     "",
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index 1772a70322..a084a145c8 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -413,6 +413,79 @@ BOOST_AUTO_TEST_CASE(script_build)
                               "P2PK NOT with too much R padding", SCRIPT_VERIFY_DERSIG
                              ).PushSig(keys.key2, SIGHASH_ALL, 31, 32).EditPush(1, "43021F", "44022000"));
 
+    good.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey1C) << OP_CHECKSIG,
+                               "BIP66 example 1, without DERSIG", 0
+                              ).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220"));
+    bad.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey1C) << OP_CHECKSIG,
+                              "BIP66 example 1, with DERSIG", SCRIPT_VERIFY_DERSIG
+                             ).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220"));
+    bad.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey1C) << OP_CHECKSIG << OP_NOT,
+                              "BIP66 example 2, without DERSIG", 0
+                             ).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220"));
+    bad.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey1C) << OP_CHECKSIG << OP_NOT,
+                              "BIP66 example 2, with DERSIG", SCRIPT_VERIFY_DERSIG
+                             ).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220"));
+    bad.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey1C) << OP_CHECKSIG,
+                              "BIP66 example 3, without DERSIG", 0
+                             ).Num(0));
+    bad.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey1C) << OP_CHECKSIG,
+                              "BIP66 example 3, with DERSIG", SCRIPT_VERIFY_DERSIG
+                             ).Num(0));
+    good.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey1C) << OP_CHECKSIG << OP_NOT,
+                               "BIP66 example 4, without DERSIG", 0
+                              ).Num(0));
+    good.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey1C) << OP_CHECKSIG << OP_NOT,
+                               "BIP66 example 4, with DERSIG", SCRIPT_VERIFY_DERSIG
+                              ).Num(0));
+    bad.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey1C) << OP_CHECKSIG,
+                              "BIP66 example 5, without DERSIG", 0
+                             ).Num(1));
+    bad.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey1C) << OP_CHECKSIG,
+                              "BIP66 example 5, with DERSIG", SCRIPT_VERIFY_DERSIG
+                             ).Num(1));
+    good.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey1C) << OP_CHECKSIG << OP_NOT,
+                               "BIP66 example 6, without DERSIG", 0
+                              ).Num(1));
+    bad.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey1C) << OP_CHECKSIG << OP_NOT,
+                              "BIP66 example 6, with DERSIG", SCRIPT_VERIFY_DERSIG
+                             ).Num(1));
+    good.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG,
+                               "BIP66 example 7, without DERSIG", 0
+                              ).Num(0).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220").PushSig(keys.key2));
+    bad.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG,
+                              "BIP66 example 7, with DERSIG", SCRIPT_VERIFY_DERSIG
+                             ).Num(0).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220").PushSig(keys.key2));
+    bad.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG << OP_NOT,
+                              "BIP66 example 8, without DERSIG", 0
+                             ).Num(0).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220").PushSig(keys.key2));
+    bad.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG << OP_NOT,
+                              "BIP66 example 8, with DERSIG", SCRIPT_VERIFY_DERSIG
+                             ).Num(0).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220").PushSig(keys.key2));
+    bad.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG,
+                              "BIP66 example 9, without DERSIG", 0
+                             ).Num(0).Num(0).PushSig(keys.key2, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220"));
+    bad.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG,
+                              "BIP66 example 9, with DERSIG", SCRIPT_VERIFY_DERSIG
+                             ).Num(0).Num(0).PushSig(keys.key2, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220"));
+    good.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG << OP_NOT,
+                               "BIP66 example 10, without DERSIG", 0
+                              ).Num(0).Num(0).PushSig(keys.key2, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220"));
+    bad.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG << OP_NOT,
+                              "BIP66 example 10, with DERSIG", SCRIPT_VERIFY_DERSIG
+                             ).Num(0).Num(0).PushSig(keys.key2, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220"));
+    bad.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG,
+                              "BIP66 example 11, without DERSIG", 0
+                             ).Num(0).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220").Num(0));
+    bad.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG,
+                              "BIP66 example 11, with DERSIG", SCRIPT_VERIFY_DERSIG
+                             ).Num(0).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220").Num(0));
+    good.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG << OP_NOT,
+                               "BIP66 example 12, without DERSIG", 0
+                              ).Num(0).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220").Num(0));
+    good.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG << OP_NOT,
+                               "BIP66 example 12, with DERSIG", SCRIPT_VERIFY_DERSIG
+                              ).Num(0).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220").Num(0));
+
     good.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey2C) << OP_CHECKSIG,
                                "P2PK with high S but no LOW_S", 0
                               ).PushSig(keys.key2, SIGHASH_ALL, 32, 33));