diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -11,10 +11,12 @@
 #include <crypto/sha256.h>
 #include <primitives/transaction.h>
 #include <pubkey.h>
+#include <script/bitfield.h>
 #include <script/script.h>
 #include <script/script_flags.h>
 #include <script/sigencoding.h>
 #include <uint256.h>
+#include <util/bitmanip.h>
 
 bool CastToBool(const valtype &vch) {
     for (size_t i = 0; i < vch.size(); i++) {
@@ -1012,63 +1014,155 @@
                                 serror, ScriptError::INVALID_STACK_OPERATION);
                         }
 
-                        // A bug causes CHECKMULTISIG to consume one extra
-                        // argument whose contents were not checked in any way.
-                        //
-                        // Unfortunately this is a potential source of
-                        // mutability, so optionally verify it is exactly equal
-                        // to zero.
-                        if ((flags & SCRIPT_VERIFY_NULLDUMMY) &&
-                            stacktop(-idxDummy).size()) {
-                            return set_error(serror,
-                                             ScriptError::SIG_NULLDUMMY);
-                        }
-
                         // Subset of script starting at the most recent
                         // codeseparator
                         CScript scriptCode(pbegincodehash, pend);
 
-                        // Remove signature for pre-fork scripts
-                        for (int k = 0; k < nSigsCount; k++) {
-                            valtype &vchSig = stacktop(-idxTopSig - k);
-                            CleanupScriptCode(scriptCode, vchSig, flags);
-                        }
-
+                        // Assuming success is usually a bad idea, but the
+                        // schnorr path can only succeed.
                         bool fSuccess = true;
-                        int nSigsRemaining = nSigsCount;
-                        int nKeysRemaining = nKeysCount;
-                        while (fSuccess && nSigsRemaining > 0) {
-                            valtype &vchSig = stacktop(
-                                -idxTopSig - (nSigsCount - nSigsRemaining));
-                            valtype &vchPubKey = stacktop(
-                                -idxTopKey - (nKeysCount - nKeysRemaining));
-
-                            // Note how this makes the exact order of
-                            // pubkey/signature evaluation distinguishable by
-                            // CHECKMULTISIG NOT if the STRICTENC flag is set.
-                            // See the script_(in)valid tests for details.
-                            if (!CheckTransactionECDSASignatureEncoding(
-                                    vchSig, flags, serror) ||
-                                !CheckPubKeyEncoding(vchPubKey, flags,
-                                                     serror)) {
+
+                        if ((flags & SCRIPT_ENABLE_SCHNORR_MULTISIG) &&
+                            stacktop(-idxDummy).size() != 0) {
+                            // SCHNORR MULTISIG
+                            static_assert(MAX_PUBKEYS_PER_MULTISIG <= 32);
+                            uint32_t checkBits = 0;
+
+                            // Dummy element is to be interpreted as a bitfield
+                            // that represent which pubkeys should be checked.
+                            valtype &vchDummy = stacktop(-idxDummy);
+                            if (!DecodeBitfield(vchDummy, nKeysCount, checkBits,
+                                                serror)) {
                                 // serror is set
                                 return false;
                             }
 
-                            // Check signature
-                            bool fOk = checker.CheckSig(vchSig, vchPubKey,
-                                                        scriptCode, flags);
+                            // The bitfield doesn't set the right number of
+                            // signatures.
+                            if (countBits(checkBits) != uint32_t(nSigsCount)) {
+                                return set_error(
+                                    serror, ScriptError::INVALID_BIT_COUNT);
+                            }
+
+                            const size_t idxBottomKey =
+                                idxTopKey + nKeysCount - 1;
+                            const size_t idxBottomSig =
+                                idxTopSig + nSigsCount - 1;
+
+                            int iKey = 0;
+                            for (int iSig = 0; iSig < nSigsCount;
+                                 iSig++, iKey++) {
+                                if ((checkBits >> iKey) == 0) {
+                                    // This is a sanity check and should be
+                                    // unrecheable.
+                                    return set_error(
+                                        serror, ScriptError::INVALID_BIT_RANGE);
+                                }
+
+                                // Find the next suitable key.
+                                while (((checkBits >> iKey) & 0x01) == 0) {
+                                    iKey++;
+                                }
 
-                            if (fOk) {
-                                nSigsRemaining--;
+                                if (iKey >= nKeysCount) {
+                                    // This is a sanity check and should be
+                                    // unrecheable.
+                                    return set_error(serror,
+                                                     ScriptError::PUBKEY_COUNT);
+                                }
+
+                                // Check the signature.
+                                valtype &vchSig =
+                                    stacktop(-idxBottomSig + iSig);
+                                valtype &vchPubKey =
+                                    stacktop(-idxBottomKey + iKey);
+
+                                // Note that only pubkeys associated with a
+                                // signature are checked for validity.
+                                if (!CheckTransactionSchnorrSignatureEncoding(
+                                        vchSig, flags, serror) ||
+                                    !CheckPubKeyEncoding(vchPubKey, flags,
+                                                         serror)) {
+                                    // serror is set
+                                    return false;
+                                }
+
+                                // Check signature
+                                if (!checker.CheckSig(vchSig, vchPubKey,
+                                                      scriptCode, flags)) {
+                                    // This can fail if the signature is empty,
+                                    // which also is a NULLFAIL error as the
+                                    // bitfield should have been null in this
+                                    // situation.
+                                    return set_error(serror,
+                                                     ScriptError::SIG_NULLFAIL);
+                                }
                             }
-                            nKeysRemaining--;
 
-                            // If there are more signatures left than keys left,
-                            // then too many signatures have failed. Exit early,
-                            // without checking any further signatures.
-                            if (nSigsRemaining > nKeysRemaining) {
-                                fSuccess = false;
+                            if ((checkBits >> iKey) != 0) {
+                                // This is a sanity check and should be
+                                // unrecheable.
+                                return set_error(
+                                    serror, ScriptError::INVALID_BIT_COUNT);
+                            }
+                        } else {
+                            // LEGACY MULTISIG (ECDSA / NULL)
+                            // A bug causes CHECKMULTISIG to consume one extra
+                            // argument whose contents were not checked in any
+                            // way.
+                            //
+                            // Unfortunately this is a potential source of
+                            // mutability, so optionally verify it is exactly
+                            // equal to zero.
+                            if ((flags & SCRIPT_VERIFY_NULLDUMMY) &&
+                                stacktop(-idxDummy).size()) {
+                                return set_error(serror,
+                                                 ScriptError::SIG_NULLDUMMY);
+                            }
+
+                            // Remove signature for pre-fork scripts
+                            for (int k = 0; k < nSigsCount; k++) {
+                                valtype &vchSig = stacktop(-idxTopSig - k);
+                                CleanupScriptCode(scriptCode, vchSig, flags);
+                            }
+
+                            int nSigsRemaining = nSigsCount;
+                            int nKeysRemaining = nKeysCount;
+                            while (fSuccess && nSigsRemaining > 0) {
+                                valtype &vchSig = stacktop(
+                                    -idxTopSig - (nSigsCount - nSigsRemaining));
+                                valtype &vchPubKey = stacktop(
+                                    -idxTopKey - (nKeysCount - nKeysRemaining));
+
+                                // Note how this makes the exact order of
+                                // pubkey/signature evaluation distinguishable
+                                // by CHECKMULTISIG NOT if the STRICTENC flag is
+                                // set. See the script_(in)valid tests for
+                                // details.
+                                if (!CheckTransactionECDSASignatureEncoding(
+                                        vchSig, flags, serror) ||
+                                    !CheckPubKeyEncoding(vchPubKey, flags,
+                                                         serror)) {
+                                    // serror is set
+                                    return false;
+                                }
+
+                                // Check signature
+                                bool fOk = checker.CheckSig(vchSig, vchPubKey,
+                                                            scriptCode, flags);
+
+                                if (fOk) {
+                                    nSigsRemaining--;
+                                }
+                                nKeysRemaining--;
+
+                                // If there are more signatures left than keys
+                                // left, then too many signatures have failed.
+                                // Exit early, without checking any further
+                                // signatures.
+                                if (nSigsRemaining > nKeysRemaining) {
+                                    fSuccess = false;
+                                }
                             }
                         }
 
diff --git a/src/script/script_error.h b/src/script/script_error.h
--- a/src/script/script_error.h
+++ b/src/script/script_error.h
@@ -25,6 +25,7 @@
     INVALID_NUMBER_RANGE,
     IMPOSSIBLE_ENCODING,
     INVALID_SPLIT_RANGE,
+    INVALID_BIT_COUNT,
 
     /* Failed verify operations */
     VERIFY,
diff --git a/src/script/script_error.cpp b/src/script/script_error.cpp
--- a/src/script/script_error.cpp
+++ b/src/script/script_error.cpp
@@ -45,6 +45,8 @@
             return "The requested encoding is impossible to satisfy";
         case ScriptError::INVALID_SPLIT_RANGE:
             return "Invalid OP_SPLIT range";
+        case ScriptError::INVALID_BIT_COUNT:
+            return "Invalid number of bit set in OP_CHECKMULTISIG";
         case ScriptError::BAD_OPCODE:
             return "Opcode missing or not understood";
         case ScriptError::DISABLED_OPCODE:
diff --git a/src/test/data/script_tests.json b/src/test/data/script_tests.json
--- a/src/test/data/script_tests.json
+++ b/src/test/data/script_tests.json
@@ -3078,6 +3078,279 @@
     "SIG_BADLENGTH",
     "recovered-pubkey CHECKMULTISIG with 64-byte DER w/ SCHNORR_MULTISIG"
 ],
+[
+    "0 0 0",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG NOT",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 2-of-3 w/ SCHNORR_MULTISIG (return-false still valid via legacy mode)"
+],
+[
+    "0",
+    "0 0 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 0-of-0 w/ SCHNORR_MULTISIG"
+],
+[
+    "0",
+    "0 0x02 0xbeef 1 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 0-of-1 w/ SCHNORR_MULTISIG, null dummy"
+],
+[
+    "1 0x41 0x105e4fed395e64ca013ac1ce020ef69b9990a577fe4b74648faafb69e499f76dd53d5c64aa866924361dd3aadde9b7184bbcb4f79520396c9ed17c4d8489a59701",
+    "1 0x41 0x0479be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8 1 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 1-of-1 Schnorr"
+],
+[
+    "0x02 0x0100 0x41 0x105e4fed395e64ca013ac1ce020ef69b9990a577fe4b74648faafb69e499f76dd53d5c64aa866924361dd3aadde9b7184bbcb4f79520396c9ed17c4d8489a59701",
+    "1 0x41 0x0479be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8 1 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "BITFIELD_SIZE",
+    "CHECKMULTISIG 1-of-1 Schnorr, nonminimal bits"
+],
+[
+    "7 0x41 0x833682d4f60cc916a22a2c263e658fa662c49badb1e2a8c6208987bf99b1abd740498371480069e7a7a6e7471bf78c27bd9a1fd04fb212a92017346250ac187b01 0x41 0xea4a8d20562a950f4695dc24804565482e9fa111704886179d0c348f2b8a15fe691a305cd599c59c131677146661d5b98cb935330989a85f33afc70d0a21add101 0x41 0xce9011d76a4df05d6280b2382b4d91490dbec7c3e72dc826be1fc9b4718f627955190745cac96521ea46d6d324c7376461e225310e6cd605b9f266d170769b7901",
+    "3 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 3-of-3 Schnorr"
+],
+[
+    "15 0x41 0x6d1d1f8db2b4e43a51b4f5f16367045f9c1832b8103ce2bab3a21afc223351a685e84bca02c863110e7ad22d4735cd31e1908e741530e3a07863292c3ff21df901 0x41 0x6d1d1f8db2b4e43a51b4f5f16367045f9c1832b8103ce2bab3a21afc223351a685e84bca02c863110e7ad22d4735cd31e1908e741530e3a07863292c3ff21df901 0x41 0x98ac816c0adb14db2a593f6402bf70e347a219fba0ccad805a5e37a67e265c800b1d493440965634fe740852fbe4164ec45a722a463099ae8a9872896da972ef01 0x41 0xe62867a73ae91b390f6ae11717d360fbc7e813a6dc3917040556834350d5b3cfb464e7222a716f37a32ba3fee353ad4957aa3f47cf7ea1285873bc9a0e64759801",
+    "4 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "SIG_COUNT",
+    "CHECKMULTISIG 4-of-3 Schnorr"
+],
+[
+    "6 0x41 0x4829a4df8042001ba6a3ee6ec1e9c26de662aade55a49f8d018acff0bac0df2edd881cf21f2a1aa651b6f703f0cde22fedaa9b8bc3451101bcac37bcb89dcc8001 0x41 0xa3fac6b1aa2cc8bb222ee379711c243b26a164ced7f2e2f4a0e184a3e53352bfaee598c6446861e5a7e819871b7ce948f5562ecf214c19dfa5112c19d74adc7101",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 2-of-3 (110) Schnorr"
+],
+[
+    "5 0x41 0xb8c744ebecfa75ef478b2b8852795d93b99640e5c05421ef6f651d4044be6cf2db2c61d0b5395e685731556c87e501433fb6e6a3b44c113d0ba19df8fd01c18101 0x41 0xa3fac6b1aa2cc8bb222ee379711c243b26a164ced7f2e2f4a0e184a3e53352bfaee598c6446861e5a7e819871b7ce948f5562ecf214c19dfa5112c19d74adc7101",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 2-of-3 (101) Schnorr"
+],
+[
+    "3 0x41 0xb8c744ebecfa75ef478b2b8852795d93b99640e5c05421ef6f651d4044be6cf2db2c61d0b5395e685731556c87e501433fb6e6a3b44c113d0ba19df8fd01c18101 0x41 0x4829a4df8042001ba6a3ee6ec1e9c26de662aade55a49f8d018acff0bac0df2edd881cf21f2a1aa651b6f703f0cde22fedaa9b8bc3451101bcac37bcb89dcc8001",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 2-of-3 (011) Schnorr"
+],
+[
+    "3 0x41 0xb8c744ebecfa75ef478b2b8852795d93b99640e5c05421ef6f651d4044be6cf2db2c61d0b5395e685731556c87e501433fb6e6a3b44c113d0ba19df8fd01c18101 0x41 0xa3fac6b1aa2cc8bb222ee379711c243b26a164ced7f2e2f4a0e184a3e53352bfaee598c6446861e5a7e819871b7ce948f5562ecf214c19dfa5112c19d74adc7101",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "NULLFAIL",
+    "CHECKMULTISIG 2-of-3 Schnorr, mismatched bits Schnorr"
+],
+[
+    "7 0x41 0x4829a4df8042001ba6a3ee6ec1e9c26de662aade55a49f8d018acff0bac0df2edd881cf21f2a1aa651b6f703f0cde22fedaa9b8bc3451101bcac37bcb89dcc8001 0x41 0xa3fac6b1aa2cc8bb222ee379711c243b26a164ced7f2e2f4a0e184a3e53352bfaee598c6446861e5a7e819871b7ce948f5562ecf214c19dfa5112c19d74adc7101",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "INVALID_BIT_COUNT",
+    "CHECKMULTISIG 2-of-3 Schnorr, all bits set"
+],
+[
+    "14 0x41 0xb8c744ebecfa75ef478b2b8852795d93b99640e5c05421ef6f651d4044be6cf2db2c61d0b5395e685731556c87e501433fb6e6a3b44c113d0ba19df8fd01c18101 0x41 0x4829a4df8042001ba6a3ee6ec1e9c26de662aade55a49f8d018acff0bac0df2edd881cf21f2a1aa651b6f703f0cde22fedaa9b8bc3451101bcac37bcb89dcc8001",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "BIT_RANGE",
+    "CHECKMULTISIG 2-of-3 Schnorr, extra high bit set"
+],
+[
+    "10 0x41 0xb8c744ebecfa75ef478b2b8852795d93b99640e5c05421ef6f651d4044be6cf2db2c61d0b5395e685731556c87e501433fb6e6a3b44c113d0ba19df8fd01c18101 0x41 0x4829a4df8042001ba6a3ee6ec1e9c26de662aade55a49f8d018acff0bac0df2edd881cf21f2a1aa651b6f703f0cde22fedaa9b8bc3451101bcac37bcb89dcc8001",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "BIT_RANGE",
+    "CHECKMULTISIG 2-of-3 Schnorr, too high bit set"
+],
+[
+    "2 0x41 0xb8c744ebecfa75ef478b2b8852795d93b99640e5c05421ef6f651d4044be6cf2db2c61d0b5395e685731556c87e501433fb6e6a3b44c113d0ba19df8fd01c18101 0x41 0x4829a4df8042001ba6a3ee6ec1e9c26de662aade55a49f8d018acff0bac0df2edd881cf21f2a1aa651b6f703f0cde22fedaa9b8bc3451101bcac37bcb89dcc8001",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "INVALID_BIT_COUNT",
+    "CHECKMULTISIG 2-of-3 Schnorr, too few bits set"
+],
+[
+    "0x01 0x00 0 0",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "INVALID_BIT_COUNT",
+    "CHECKMULTISIG 2-of-3 Schnorr, with no bits set (attempt to malleate return-false)"
+],
+[
+    "0 0x41 0xb8c744ebecfa75ef478b2b8852795d93b99640e5c05421ef6f651d4044be6cf2db2c61d0b5395e685731556c87e501433fb6e6a3b44c113d0ba19df8fd01c18101 0x41 0x4829a4df8042001ba6a3ee6ec1e9c26de662aade55a49f8d018acff0bac0df2edd881cf21f2a1aa651b6f703f0cde22fedaa9b8bc3451101bcac37bcb89dcc8001",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "SIG_BADLENGTH",
+    "CHECKMULTISIG null dummy with schnorr sigs (with SCHNORR_MULTISIG on)"
+],
+[
+    "3 0x41 0x4829a4df8042001ba6a3ee6ec1e9c26de662aade55a49f8d018acff0bac0df2edd881cf21f2a1aa651b6f703f0cde22fedaa9b8bc3451101bcac37bcb89dcc8001 0x41 0xb8c744ebecfa75ef478b2b8852795d93b99640e5c05421ef6f651d4044be6cf2db2c61d0b5395e685731556c87e501433fb6e6a3b44c113d0ba19df8fd01c18101",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "NULLFAIL",
+    "CHECKMULTISIG 2-of-3 Schnorr, misordered signatures"
+],
+[
+    "-1 0x41 0x34b9918c9cd9aa3ad0f642f1dd435164e7bed979e539b2890b8d465b70db47385c514a21b1c6659ab40b8e5395ceae8f6c67c6f4c24e940cbe0a6fe496e7d15e01 0x41 0x057e3e62dbcf8a1bd3526271ad63f568bdae4d248bd87dfcf4a80b9f6da28e0994e04c670a56e624301141f53efc9a40f7d503171809e3f70d5aee203a90567d01",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 DUP 2DUP 2DUP 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 8 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 2-of-8 Schnorr, right way to represent 0b10000001"
+],
+[
+    "0x02 0x8100 0x41 0x34b9918c9cd9aa3ad0f642f1dd435164e7bed979e539b2890b8d465b70db47385c514a21b1c6659ab40b8e5395ceae8f6c67c6f4c24e940cbe0a6fe496e7d15e01 0x41 0x057e3e62dbcf8a1bd3526271ad63f568bdae4d248bd87dfcf4a80b9f6da28e0994e04c670a56e624301141f53efc9a40f7d503171809e3f70d5aee203a90567d01",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 DUP 2DUP 2DUP 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 8 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "BITFIELD_SIZE",
+    "CHECKMULTISIG 2-of-8 Schnorr, wrong way to represent 0b10000001"
+],
+[
+    "0x03 0xffff0f 0x41 0x5f4f7ffff1fa44347dbc148d51fe661b60fbc44b5abe22a04d97ecfb891bdb2568eb91aa38a426dfd7b82e0b45b57af6f3e56143fabc850ebfdfcf6a0d03c4b001 0x41 0x28add881f6fa489a9016f066022ed80acecbafc351a6d17025cf87bf2b0d9b09f6d001f5df2b1be0d1909a8fe9280b59b5a8cb6d1e37425e733ff3267ce1e1b401 0x41 0x9f66f20bca4a64fc3cc170c3e1ef2bcb62f86b719b2f8e7154407e9210fde99164d754f787bf65020dc7db3838c8aae3591eaf465f45433fcb3d0a94bea4090401",
+    "OVER DUP DUP 2DUP 3DUP 3DUP 3DUP 3DUP 0x01 0x14 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 OVER DUP DUP 2DUP 3DUP 3DUP 3DUP 3DUP 0x01 0x14 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 20-of-20 Schnorr"
+],
+[
+    "0x03 0x000010 0x41 0x5f4f7ffff1fa44347dbc148d51fe661b60fbc44b5abe22a04d97ecfb891bdb2568eb91aa38a426dfd7b82e0b45b57af6f3e56143fabc850ebfdfcf6a0d03c4b001 0x41 0x28add881f6fa489a9016f066022ed80acecbafc351a6d17025cf87bf2b0d9b09f6d001f5df2b1be0d1909a8fe9280b59b5a8cb6d1e37425e733ff3267ce1e1b401 0x41 0x9f66f20bca4a64fc3cc170c3e1ef2bcb62f86b719b2f8e7154407e9210fde99164d754f787bf65020dc7db3838c8aae3591eaf465f45433fcb3d0a94bea4090401",
+    "OVER DUP DUP 2DUP 3DUP 3DUP 3DUP 3DUP 0x01 0x14 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 OVER DUP DUP 2DUP 3DUP 3DUP 3DUP 3DUP 0x01 0x14 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "BIT_RANGE",
+    "CHECKMULTISIG 20-of-20 Schnorr, checkbits +1"
+],
+[
+    "0x03 0x000010 0x41 0xbe6635b93b92ff98d0d929d3537bf2941bbc33b9b4adc14d928e1b6eae1aa1fd23455e4094764f70dd896f47b3279b57965ecad1b4d32c1000be27be8cf83ece01",
+    "1 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 DUP 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 3DUP 3DUP 3DUP 3DUP 3DUP 3DUP 0x01 0x15 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "PUBKEY_COUNT",
+    "CHECKMULTISIG 1-of-21 Schnorr"
+],
+[
+    "0x03 0x010000 0x41 0x020fb4d03e4c7ea6e17f5a7d03c74a6cc33fd7f949d6bc5eb8f6122a4fa5a9bc208adafc7a92030fea664f044cccfd473b8ebaae94cd7bdeec8346a02ac0e3df01",
+    "1 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 DUP 2DUP 3DUP 3DUP 3DUP 3DUP 3DUP 0x01 0x14 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 1-of-20 Schnorr, first key"
+],
+[
+    "0x03 0x000001 0x41 0x020fb4d03e4c7ea6e17f5a7d03c74a6cc33fd7f949d6bc5eb8f6122a4fa5a9bc208adafc7a92030fea664f044cccfd473b8ebaae94cd7bdeec8346a02ac0e3df01",
+    "1 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 DUP 2DUP 3DUP 3DUP 3DUP 3DUP 3DUP 0x01 0x14 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "NULLFAIL",
+    "CHECKMULTISIG 1-of-20 Schnorr, first key, wrong endianness"
+],
+[
+    "1 0x41 0xf92f753aa4238dfce5e2c68a5bb9f04c4a457c775ef247a2fda9318d2b6ab086cf7d116a24f38a045d179ff59d84c872e9fc2ef0f7574306c22380cd18da411301",
+    "1 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 2DUP 2DUP 3DUP 3DUP 3DUP 3DUP 3DUP 0x01 0x14 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "BITFIELD_SIZE",
+    "CHECKMULTISIG 1-of-20 Schnorr, truncating zeros not allowed"
+],
+[
+    "0x03 0x000008 0x41 0xdbcb269b86b9b0abb01fdf0a38b3ba9852150188bb2255e4a0794ecbbdcba52a6577ca08e0dd89b9543cae1bcf152e5444ee70759bc58a553a4c1e41144fc27001",
+    "1 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 DUP 2DUP 3DUP 3DUP 3DUP 3DUP 3DUP 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x01 0x14 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 1-of-20 Schnorr, last key"
+],
+[
+    "0x03 0x080000 0x41 0xdbcb269b86b9b0abb01fdf0a38b3ba9852150188bb2255e4a0794ecbbdcba52a6577ca08e0dd89b9543cae1bcf152e5444ee70759bc58a553a4c1e41144fc27001",
+    "1 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 DUP 2DUP 3DUP 3DUP 3DUP 3DUP 3DUP 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x01 0x14 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "NULLFAIL",
+    "CHECKMULTISIG 1-of-20 Schnorr, last key, wrong endianness"
+],
+[
+    "0x02 0x0800 0x41 0xdbcb269b86b9b0abb01fdf0a38b3ba9852150188bb2255e4a0794ecbbdcba52a6577ca08e0dd89b9543cae1bcf152e5444ee70759bc58a553a4c1e41144fc27001",
+    "1 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 DUP 2DUP 3DUP 3DUP 3DUP 3DUP 3DUP 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x01 0x14 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "BITFIELD_SIZE",
+    "CHECKMULTISIG 1-of-20 Schnorr, last key, truncating zeros not allowed"
+],
+[
+    "6 0x41 0x3dfd744897afdad123edf671b9f7ad99f884cf714ada36f4c1cba12f7bdc71c6369832821a91964eb7d05552f1e32e5506d6dc2262e3ca5d1238690e3ddb075401 0x41 0x84aa5be4ebc905d6390a5be1b0101a0f2aab9563603a52c864db5deb459266cf1ea4376d378aa69a907a4e255919ecbff044d21b76dd004d34266c7ad8b84af501",
+    "2 0x02 0xbeef 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 2-of-3 (110) Schnorr, first key garbage"
+],
+[
+    "3 0x41 0xb7aa94db79ecf22bdfd4d986ac4ba294fc044dd75696a6f95b12fef2dee48e02e06ccda571e0d513a03c585f86a8df1223a02556c11d7f1da71ba10544e9bc9501 0x41 0x3dfd744897afdad123edf671b9f7ad99f884cf714ada36f4c1cba12f7bdc71c6369832821a91964eb7d05552f1e32e5506d6dc2262e3ca5d1238690e3ddb075401",
+    "2 0x02 0xbeef 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "PUBKEYTYPE",
+    "CHECKMULTISIG 2-of-3 (011) Schnorr, first key garbage"
+],
+[
+    "3 0x41 0xc09a62bbf5b7e45503a682cc72559b4d060edf1144023b47e765375a8e0cb017da3b0b72e2912a772989ce922f7f298890e66ff9f36c813b872682fc6b95a04b01 0x41 0x7e57eab163176c372e6f2baa2446998817b429d9cd8e3ee3a6841a95bf19fa128562848b590bf2ada480a23bbb6697f3e920594e7bf410b3b8af489862ee660601",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x02 0xbeef 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 2-of-3 (011) Schnorr, last key garbage"
+],
+[
+    "6 0x41 0x7e57eab163176c372e6f2baa2446998817b429d9cd8e3ee3a6841a95bf19fa128562848b590bf2ada480a23bbb6697f3e920594e7bf410b3b8af489862ee660601 0x41 0x64b53fe45bc169d53366fe20f7340596ba9ad86566ae725535e32c5a40d4d3dbd448bc898d0528395eca1c634e4ce422c856c6063cb947d8191127317da4a5a001",
+    "2 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x02 0xbeef 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "PUBKEYTYPE",
+    "CHECKMULTISIG 2-of-3 (110) Schnorr, last key garbage"
+],
+[
+    "0x01 0x00",
+    "0 0 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "BITFIELD_SIZE",
+    "CHECKMULTISIG 0-of-0 with SCHNORR_MULTISIG, dummy must be null"
+],
+[
+    "0x01 0x00",
+    "0 0x02 0xbeef 1 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "CHECKMULTISIG 0-of-1 with SCHNORR_MULTISIG, dummy need not be null"
+],
+[
+    "1 0x41 0x105e4fed395e64ca013ac1ce020ef69b9990a577fe4b74648faafb69e499f76dd53d5c64aa866924361dd3aadde9b7184bbcb4f79520396c9ed17c4d8489a59701",
+    "1 0x41 0x0479be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8 1 CHECKMULTISIG",
+    "MINIMALDATA,NULLDUMMY,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "SCHNORR_MULTISIG implies that NULLDUMMY flag has no effect"
+],
+[
+    "1 0x41 0x17fa4dd3e62694cc7816d32b73d5646ea768072aea4926a09e159e5f57be8fd6523800b259fe2a12e27aa29a3719f19e9e4b99d7f8e465a6f19454f914ccb3ec01",
+    "1 0x41 0x0479be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8 1 CHECKMULTISIGVERIFY 1",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "OK",
+    "OP_CHECKMULTISIGVERIFY Schnorr"
+],
+[
+    "1 0x47 0x304402204d0106d6babcaca95277692eaa566bdc89d9f44b1106c18423345c7e9ac40d79022033a3750421038d15f15101ffdca1147a0eb980bb1b809280cb5368c50c10c42c01",
+    "1 0x41 0x0479be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8 1 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "SIG_NONSCHNORR",
+    "CHECKMULTISIG 1-of-1 ECDSA signature in Schnorr mode"
+],
+[
+    "7 0x47 0x304402204d69d5caa4dbab259f79fce89d3b459bbd91697c1c052a1554ff3b08b2241cbd0220330a8e17a90d51996e363cb8902fce6278c6350fa59ae12832db2f6a44d64dce01 0x41 0xea4a8d20562a950f4695dc24804565482e9fa111704886179d0c348f2b8a15fe691a305cd599c59c131677146661d5b98cb935330989a85f33afc70d0a21add101 0x41 0xce9011d76a4df05d6280b2382b4d91490dbec7c3e72dc826be1fc9b4718f627955190745cac96521ea46d6d324c7376461e225310e6cd605b9f266d170769b7901",
+    "3 0x21 0x0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 0x21 0x038282263212c609d9ea2a6e3e172de238d8c39cabd5ac1ca10646e23fd5f51508 0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 3 CHECKMULTISIG",
+    "MINIMALDATA,NULLFAIL,SCHNORR_MULTISIG,STRICTENC",
+    "SIG_NONSCHNORR",
+    "CHECKMULTISIG 3-of-3 Schnorr with mixed-in ECDSA signature"
+],
 
 ["CHECKSEQUENCEVERIFY tests"],
 ["", "CHECKSEQUENCEVERIFY", "CHECKSEQUENCEVERIFY", "INVALID_STACK_OPERATION", "CSV automatically fails on an empty stack"],
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -36,7 +36,7 @@
 #include <vector>
 
 // Uncomment if you want to output updated JSON tests.
-// #define UPDATE_JSON_TESTS
+#define UPDATE_JSON_TESTS
 
 static const uint32_t gFlags = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC;
 
@@ -60,6 +60,7 @@
     {ScriptError::INVALID_NUMBER_RANGE, "INVALID_NUMBER_RANGE"},
     {ScriptError::IMPOSSIBLE_ENCODING, "IMPOSSIBLE_ENCODING"},
     {ScriptError::INVALID_SPLIT_RANGE, "SPLIT_RANGE"},
+    {ScriptError::INVALID_BIT_COUNT, "INVALID_BIT_COUNT"},
     {ScriptError::VERIFY, "VERIFY"},
     {ScriptError::EQUALVERIFY, "EQUALVERIFY"},
     {ScriptError::CHECKMULTISIGVERIFY, "CHECKMULTISIGVERIFY"},
@@ -91,6 +92,8 @@
     {ScriptError::MUST_USE_FORKID, "MISSING_FORKID"},
     {ScriptError::DIV_BY_ZERO, "DIV_BY_ZERO"},
     {ScriptError::MOD_BY_ZERO, "MOD_BY_ZERO"},
+    {ScriptError::INVALID_BITFIELD_SIZE, "BITFIELD_SIZE"},
+    {ScriptError::INVALID_BIT_RANGE, "BIT_RANGE"},
 };
 
 static const char *FormatScriptError(ScriptError err) {
@@ -1843,6 +1846,393 @@
                             .PushECDSARecoveredPubKey(rdata, sdata)
                             .SetScriptError(ScriptError::SIG_BADLENGTH));
     }
+    tests.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                                          << ToByteVector(keys.pubkey1C)
+                                          << ToByteVector(keys.pubkey2C) << OP_3
+                                          << OP_CHECKMULTISIG << OP_NOT,
+                                "CHECKMULTISIG 2-of-3 w/ SCHNORR_MULTISIG "
+                                "(return-false still valid via legacy mode)",
+                                newmultisigflags)
+                        .Num(0)
+                        .Num(0)
+                        .Num(0));
+    tests.push_back(TestBuilder(CScript() << OP_0 << OP_0 << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG 0-of-0 w/ SCHNORR_MULTISIG",
+                                newmultisigflags)
+                        .Num(0));
+    tests.push_back(
+        TestBuilder(CScript() << OP_0 << ToByteVector(ParseHex("BEEF")) << OP_1
+                              << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 0-of-1 w/ SCHNORR_MULTISIG, null dummy",
+                    newmultisigflags)
+            .Num(0));
+
+    // Tests of schnorr checkmultisig actually turned on (flag on & dummy
+    // element is not null).
+    tests.push_back(TestBuilder(CScript() << OP_1 << ToByteVector(keys.pubkey0)
+                                          << OP_1 << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG 1-of-1 Schnorr",
+                                newmultisigflags)
+                        .Num(0b1)
+                        .PushSigSchnorr(keys.key0));
+    tests.push_back(TestBuilder(CScript() << OP_1 << ToByteVector(keys.pubkey0)
+                                          << OP_1 << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG 1-of-1 Schnorr, nonminimal bits",
+                                newmultisigflags)
+                        .Push("0100")
+                        .PushSigSchnorr(keys.key0)
+                        .SetScriptError(ScriptError::INVALID_BITFIELD_SIZE));
+    tests.push_back(TestBuilder(CScript() << OP_3 << ToByteVector(keys.pubkey0C)
+                                          << ToByteVector(keys.pubkey1C)
+                                          << ToByteVector(keys.pubkey2C) << OP_3
+                                          << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG 3-of-3 Schnorr",
+                                newmultisigflags)
+                        .Num(0b111)
+                        .PushSigSchnorr(keys.key0)
+                        .PushSigSchnorr(keys.key1)
+                        .PushSigSchnorr(keys.key2));
+    tests.push_back(TestBuilder(CScript() << OP_4 << ToByteVector(keys.pubkey0C)
+                                          << ToByteVector(keys.pubkey1C)
+                                          << ToByteVector(keys.pubkey2C) << OP_3
+                                          << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG 4-of-3 Schnorr",
+                                newmultisigflags)
+                        .Num(0b1111)
+                        .PushSigSchnorr(keys.key0)
+                        .PushSigSchnorr(keys.key0)
+                        .PushSigSchnorr(keys.key1)
+                        .PushSigSchnorr(keys.key2)
+                        .SetScriptError(ScriptError::SIG_COUNT));
+    tests.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                                          << ToByteVector(keys.pubkey1C)
+                                          << ToByteVector(keys.pubkey2C) << OP_3
+                                          << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG 2-of-3 (110) Schnorr",
+                                newmultisigflags)
+                        .Num(0b110)
+                        .PushSigSchnorr(keys.key1)
+                        .PushSigSchnorr(keys.key2));
+    tests.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                                          << ToByteVector(keys.pubkey1C)
+                                          << ToByteVector(keys.pubkey2C) << OP_3
+                                          << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG 2-of-3 (101) Schnorr",
+                                newmultisigflags)
+                        .Num(0b101)
+                        .PushSigSchnorr(keys.key0)
+                        .PushSigSchnorr(keys.key2));
+    tests.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                                          << ToByteVector(keys.pubkey1C)
+                                          << ToByteVector(keys.pubkey2C) << OP_3
+                                          << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG 2-of-3 (011) Schnorr",
+                                newmultisigflags)
+                        .Num(0b011)
+                        .PushSigSchnorr(keys.key0)
+                        .PushSigSchnorr(keys.key1));
+    tests.push_back(
+        TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                              << ToByteVector(keys.pubkey1C)
+                              << ToByteVector(keys.pubkey2C) << OP_3
+                              << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 2-of-3 Schnorr, mismatched bits Schnorr",
+                    newmultisigflags)
+            .Num(0b011)
+            .PushSigSchnorr(keys.key0)
+            .PushSigSchnorr(keys.key2)
+            .SetScriptError(ScriptError::SIG_NULLFAIL));
+    tests.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                                          << ToByteVector(keys.pubkey1C)
+                                          << ToByteVector(keys.pubkey2C) << OP_3
+                                          << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG 2-of-3 Schnorr, all bits set",
+                                newmultisigflags)
+                        .Num(0b111)
+                        .PushSigSchnorr(keys.key1)
+                        .PushSigSchnorr(keys.key2)
+                        .SetScriptError(ScriptError::INVALID_BIT_COUNT));
+    tests.push_back(
+        TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                              << ToByteVector(keys.pubkey1C)
+                              << ToByteVector(keys.pubkey2C) << OP_3
+                              << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 2-of-3 Schnorr, extra high bit set",
+                    newmultisigflags)
+            .Num(0b1110)
+            .PushSigSchnorr(keys.key0)
+            .PushSigSchnorr(keys.key1)
+            .SetScriptError(ScriptError::INVALID_BIT_RANGE));
+    tests.push_back(
+        TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                              << ToByteVector(keys.pubkey1C)
+                              << ToByteVector(keys.pubkey2C) << OP_3
+                              << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 2-of-3 Schnorr, too high bit set",
+                    newmultisigflags)
+            .Num(0b1010)
+            .PushSigSchnorr(keys.key0)
+            .PushSigSchnorr(keys.key1)
+            .SetScriptError(ScriptError::INVALID_BIT_RANGE));
+    tests.push_back(
+        TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                              << ToByteVector(keys.pubkey1C)
+                              << ToByteVector(keys.pubkey2C) << OP_3
+                              << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 2-of-3 Schnorr, too few bits set",
+                    newmultisigflags)
+            .Num(0b010)
+            .PushSigSchnorr(keys.key0)
+            .PushSigSchnorr(keys.key1)
+            .SetScriptError(ScriptError::INVALID_BIT_COUNT));
+    tests.push_back(
+        TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                              << ToByteVector(keys.pubkey1C)
+                              << ToByteVector(keys.pubkey2C) << OP_3
+                              << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 2-of-3 Schnorr, with no bits set "
+                    "(attempt to malleate return-false)",
+                    newmultisigflags)
+            .Push("00")
+            .Num(0)
+            .Num(0)
+            .SetScriptError(ScriptError::INVALID_BIT_COUNT));
+    tests.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                                          << ToByteVector(keys.pubkey1C)
+                                          << ToByteVector(keys.pubkey2C) << OP_3
+                                          << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG null dummy with schnorr sigs "
+                                "(with SCHNORR_MULTISIG on)",
+                                newmultisigflags)
+                        .Num(0)
+                        .PushSigSchnorr(keys.key0)
+                        .PushSigSchnorr(keys.key1)
+                        .SetScriptError(ScriptError::SIG_BADLENGTH));
+    tests.push_back(
+        TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                              << ToByteVector(keys.pubkey1C)
+                              << ToByteVector(keys.pubkey2C) << OP_3
+                              << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 2-of-3 Schnorr, misordered signatures",
+                    newmultisigflags)
+            .Num(0b011)
+            .PushSigSchnorr(keys.key1)
+            .PushSigSchnorr(keys.key0)
+            .SetScriptError(ScriptError::SIG_NULLFAIL));
+    tests.push_back(
+        TestBuilder(
+            CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                      << ToByteVector(keys.pubkey1C) << OP_DUP << OP_2DUP
+                      << OP_2DUP << ToByteVector(keys.pubkey2C) << OP_8
+                      << OP_CHECKMULTISIG,
+            "CHECKMULTISIG 2-of-8 Schnorr, right way to represent 0b10000001",
+            newmultisigflags)
+            .Num(-1)
+            .PushSigSchnorr(keys.key0)
+            .PushSigSchnorr(keys.key2));
+    tests.push_back(
+        TestBuilder(
+            CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                      << ToByteVector(keys.pubkey1C) << OP_DUP << OP_2DUP
+                      << OP_2DUP << ToByteVector(keys.pubkey2C) << OP_8
+                      << OP_CHECKMULTISIG,
+            "CHECKMULTISIG 2-of-8 Schnorr, wrong way to represent 0b10000001",
+            newmultisigflags)
+            .Num(0b10000001)
+            .PushSigSchnorr(keys.key0)
+            .PushSigSchnorr(keys.key2)
+            .SetScriptError(ScriptError::INVALID_BITFIELD_SIZE));
+    tests.push_back(
+        TestBuilder(CScript()
+                        << OP_OVER << OP_DUP << OP_DUP << OP_2DUP << OP_3DUP
+                        << OP_3DUP << OP_3DUP << OP_3DUP << 20
+                        << ToByteVector(keys.pubkey0C)
+                        << ToByteVector(keys.pubkey1C)
+                        << ToByteVector(keys.pubkey2C) << OP_OVER << OP_DUP
+                        << OP_DUP << OP_2DUP << OP_3DUP << OP_3DUP << OP_3DUP
+                        << OP_3DUP << 20 << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 20-of-20 Schnorr", newmultisigflags)
+            .Push("ffff0f")
+            .PushSigSchnorr(keys.key0)
+            .PushSigSchnorr(keys.key1)
+            .PushSigSchnorr(keys.key2));
+    tests.push_back(
+        TestBuilder(
+            CScript() << OP_OVER << OP_DUP << OP_DUP << OP_2DUP << OP_3DUP
+                      << OP_3DUP << OP_3DUP << OP_3DUP << 20
+                      << ToByteVector(keys.pubkey0C)
+                      << ToByteVector(keys.pubkey1C)
+                      << ToByteVector(keys.pubkey2C) << OP_OVER << OP_DUP
+                      << OP_DUP << OP_2DUP << OP_3DUP << OP_3DUP << OP_3DUP
+                      << OP_3DUP << 20 << OP_CHECKMULTISIG,
+            "CHECKMULTISIG 20-of-20 Schnorr, checkbits +1", newmultisigflags)
+            .Push("000010")
+            .PushSigSchnorr(keys.key0)
+            .PushSigSchnorr(keys.key1)
+            .PushSigSchnorr(keys.key2)
+            .SetScriptError(ScriptError::INVALID_BIT_RANGE));
+    tests.push_back(
+        TestBuilder(CScript() << OP_1 << ToByteVector(keys.pubkey0C) << OP_DUP
+                              << ToByteVector(keys.pubkey1C) << OP_3DUP
+                              << OP_3DUP << OP_3DUP << OP_3DUP << OP_3DUP
+                              << OP_3DUP << 21 << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 1-of-21 Schnorr", newmultisigflags)
+            .Push("000010")
+            .PushSigSchnorr(keys.key0)
+            .SetScriptError(ScriptError::PUBKEY_COUNT));
+    tests.push_back(TestBuilder(CScript() << OP_1 << ToByteVector(keys.pubkey0C)
+                                          << ToByteVector(keys.pubkey1C)
+                                          << OP_DUP << OP_2DUP << OP_3DUP
+                                          << OP_3DUP << OP_3DUP << OP_3DUP
+                                          << OP_3DUP << 20 << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG 1-of-20 Schnorr, first key",
+                                newmultisigflags)
+                        .Push("010000")
+                        .PushSigSchnorr(keys.key0));
+    tests.push_back(
+        TestBuilder(
+            CScript() << OP_1 << ToByteVector(keys.pubkey0C)
+                      << ToByteVector(keys.pubkey1C) << OP_DUP << OP_2DUP
+                      << OP_3DUP << OP_3DUP << OP_3DUP << OP_3DUP << OP_3DUP
+                      << 20 << OP_CHECKMULTISIG,
+            "CHECKMULTISIG 1-of-20 Schnorr, first key, wrong endianness",
+            newmultisigflags)
+            .Push("000001")
+            .PushSigSchnorr(keys.key0)
+            .SetScriptError(ScriptError::SIG_NULLFAIL));
+    tests.push_back(
+        TestBuilder(
+            CScript() << OP_1 << ToByteVector(keys.pubkey0C) << OP_2DUP
+                      << OP_2DUP << OP_3DUP << OP_3DUP << OP_3DUP << OP_3DUP
+                      << OP_3DUP << 20 << OP_CHECKMULTISIG,
+            "CHECKMULTISIG 1-of-20 Schnorr, truncating zeros not allowed",
+            newmultisigflags)
+            .Num(1)
+            .PushSigSchnorr(keys.key0)
+            .SetScriptError(ScriptError::INVALID_BITFIELD_SIZE));
+    tests.push_back(
+        TestBuilder(CScript()
+                        << OP_1 << ToByteVector(keys.pubkey0C) << OP_DUP
+                        << OP_2DUP << OP_3DUP << OP_3DUP << OP_3DUP << OP_3DUP
+                        << OP_3DUP << ToByteVector(keys.pubkey1C) << 20
+                        << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 1-of-20 Schnorr, last key", newmultisigflags)
+            .Push("000008")
+            .PushSigSchnorr(keys.key1));
+    tests.push_back(
+        TestBuilder(CScript()
+                        << OP_1 << ToByteVector(keys.pubkey0C) << OP_DUP
+                        << OP_2DUP << OP_3DUP << OP_3DUP << OP_3DUP << OP_3DUP
+                        << OP_3DUP << ToByteVector(keys.pubkey1C) << 20
+                        << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 1-of-20 Schnorr, last key, wrong endianness",
+                    newmultisigflags)
+            .Push("080000")
+            .PushSigSchnorr(keys.key1)
+            .SetScriptError(ScriptError::SIG_NULLFAIL));
+    tests.push_back(TestBuilder(CScript()
+                                    << OP_1 << ToByteVector(keys.pubkey0C)
+                                    << OP_DUP << OP_2DUP << OP_3DUP << OP_3DUP
+                                    << OP_3DUP << OP_3DUP << OP_3DUP
+                                    << ToByteVector(keys.pubkey1C) << 20
+                                    << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG 1-of-20 Schnorr, last key, "
+                                "truncating zeros not allowed",
+                                newmultisigflags)
+                        .Push("0800")
+                        .PushSigSchnorr(keys.key1)
+                        .SetScriptError(ScriptError::INVALID_BITFIELD_SIZE));
+    tests.push_back(
+        TestBuilder(CScript() << OP_2 << ToByteVector(ParseHex("BEEF"))
+                              << ToByteVector(keys.pubkey1C)
+                              << ToByteVector(keys.pubkey2C) << OP_3
+                              << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 2-of-3 (110) Schnorr, first key garbage",
+                    newmultisigflags)
+            .Num(0b110)
+            .PushSigSchnorr(keys.key1)
+            .PushSigSchnorr(keys.key2));
+    tests.push_back(
+        TestBuilder(CScript() << OP_2 << ToByteVector(ParseHex("BEEF"))
+                              << ToByteVector(keys.pubkey1C)
+                              << ToByteVector(keys.pubkey2C) << OP_3
+                              << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 2-of-3 (011) Schnorr, first key garbage",
+                    newmultisigflags)
+            .Num(0b011)
+            .PushSigSchnorr(keys.key0)
+            .PushSigSchnorr(keys.key1)
+            .SetScriptError(ScriptError::PUBKEYTYPE));
+    tests.push_back(
+        TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                              << ToByteVector(keys.pubkey1C)
+                              << ToByteVector(ParseHex("BEEF")) << OP_3
+                              << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 2-of-3 (011) Schnorr, last key garbage",
+                    newmultisigflags)
+            .Num(0b011)
+            .PushSigSchnorr(keys.key0)
+            .PushSigSchnorr(keys.key1));
+    tests.push_back(
+        TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey0C)
+                              << ToByteVector(keys.pubkey1C)
+                              << ToByteVector(ParseHex("BEEF")) << OP_3
+                              << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 2-of-3 (110) Schnorr, last key garbage",
+                    newmultisigflags)
+            .Num(0b110)
+            .PushSigSchnorr(keys.key1)
+            .PushSigSchnorr(keys.key2)
+            .SetScriptError(ScriptError::PUBKEYTYPE));
+    tests.push_back(
+        TestBuilder(
+            CScript() << OP_0 << OP_0 << OP_CHECKMULTISIG,
+            "CHECKMULTISIG 0-of-0 with SCHNORR_MULTISIG, dummy must be null",
+            newmultisigflags)
+            .Push("00")
+            .SetScriptError(ScriptError::INVALID_BITFIELD_SIZE));
+    tests.push_back(TestBuilder(CScript()
+                                    << OP_0 << ToByteVector(ParseHex("BEEF"))
+                                    << OP_1 << OP_CHECKMULTISIG,
+                                "CHECKMULTISIG 0-of-1 with SCHNORR_MULTISIG, "
+                                "dummy need not be null",
+                                newmultisigflags)
+                        .Push("00"));
+    tests.push_back(
+        TestBuilder(
+            CScript() << OP_1 << ToByteVector(keys.pubkey0) << OP_1
+                      << OP_CHECKMULTISIG,
+            "SCHNORR_MULTISIG implies that NULLDUMMY flag has no effect",
+            newmultisigflags | SCRIPT_VERIFY_NULLDUMMY)
+            .Num(0b1)
+            .PushSigSchnorr(keys.key0));
+    tests.push_back(
+        TestBuilder(CScript() << OP_1 << ToByteVector(keys.pubkey0) << OP_1
+                              << OP_CHECKMULTISIGVERIFY << OP_1,
+                    "OP_CHECKMULTISIGVERIFY Schnorr", newmultisigflags)
+            .Num(0b1)
+            .PushSigSchnorr(keys.key0));
+    tests.push_back(
+        TestBuilder(CScript() << OP_1 << ToByteVector(keys.pubkey0) << OP_1
+                              << OP_CHECKMULTISIG,
+                    "CHECKMULTISIG 1-of-1 ECDSA signature in Schnorr mode",
+                    newmultisigflags)
+            .Num(0b1)
+            .PushSigECDSA(keys.key0)
+            .SetScriptError(ScriptError::SIG_NONSCHNORR));
+    tests.push_back(
+        TestBuilder(
+            CScript() << OP_3 << ToByteVector(keys.pubkey0C)
+                      << ToByteVector(keys.pubkey1C)
+                      << ToByteVector(keys.pubkey2C) << OP_3
+                      << OP_CHECKMULTISIG,
+            "CHECKMULTISIG 3-of-3 Schnorr with mixed-in ECDSA signature",
+            newmultisigflags)
+            .Num(0b111)
+            .PushSigECDSA(keys.key0)
+            .PushSigSchnorr(keys.key1)
+            .PushSigSchnorr(keys.key2)
+            .SetScriptError(ScriptError::SIG_NONSCHNORR));
 
     std::set<std::string> tests_set;