2

I'm playing with OP_CHECKSEQUENCEVERIFY.

Here is my transaction that I'm trying to spend:

https://tchain.btc.com/e79d469698915aa6724288ae3a4141a31706d081f39fb7fd0b956a73a9044b22

which has the folowing redeem script:

2 OP_CHECKSEQUENCEVERIFY f45d94733d430261962932e0c847075195916a04 OP_CHECKSIG

But got an error when I broadcast it (after two block confirmations left):

mandatory-script-verify-flag-failed (Non-canonical DER signature) (code 16)

I have no issues to spend transaction if I:

  1. Just specify 2 CHECKLOCKTIMEVERIFY (can spend anyone)
  2. With standart transaction HASH160 f45d94733d430261962932e0c847075195916a04 OP_EQUAL

but none with combination of them. Here is a signed transaction:

0200000001224b04a9736a950bfdb79ff381d00617a341413aae884272a65a919896469de7000000006b4830450221008801d7f0e402724b090133ec01a817e993675a44a871f1a3afc0dba730e24ea4022044097be610bece524e90a743fa9d060cd194079105e6f6d150265a1164e722c3012103e8546cfe53ca9014f6a352bc2e5c1f7cec1f5b344c73d4db3ed3b8f075d5c9ef020000000120a107000000000017a914f45d94733d430261962932e0c847075195916a048700000000

Can someone explain me what I'm doing wrong?

P.S. With the folowing redeem script (OP_DROP added)

https://tchain.btc.com/022d42355ac90e63f2667208112cf22471397dd2812645b5571da2d212596932

2 OP_CHECKSEQUENCEVERIFY OP_DROP f45d94733d430261962932e0c847075195916a04 OP_CHECKSIG

I got another error 

(Script evaluated without error but finished with a false/empty top stack element) (code 16)

[UPDATED]:

https://tchain.btc.com/46894d9dd5e20147826523b1a3ac8e8c5c64603338430d04bd6f5846af2bb9b4

3 OP_CHECKSEQUENCEVERIFY OP_DROP OP_HASH160 f45d94733d430261962932e0c847075195916a04 OP_EQUAL

Then trying to broadcast this tx:

0200000001b4b92baf46586fbd040d43383360645c8c8eaca3b12365824701e2d59d4d8946000000006a47304402205649f715d2553cc4a66dd36a61b3c1b187d19f585bd40427d795c600373a45ab02203325ef44a3aae191ed3f2a90efe382d7992712c03f249f8dd61d8a30997806dc012103e8546cfe53ca9014f6a352bc2e5c1f7cec1f5b344c73d4db3ed3b8f075d5c9ef0300000001e00f97000000000017a914f45d94733d430261962932e0c847075195916a048700000000

I got 

error code: -26
error message:
mandatory-script-verify-flag-failed (Script evaluated without error but finished with a false/empty top stack element) (code 16)

Here is a privatekey 

cUB1iazKDHngknjpTHUfKtH9zNRvHn1aBMPJbK2s913zUegjkeNn

Can someone spend it?

Andrew
  • 173
  • 8

1 Answers1

2

You must provide a scriptSig that, when executed with scriptPubKey results in a true (or any nonzero item) on the stack (and passes all verification ops).

The scriptPubKey you need to satisfy (with a scriptSig) is:

2 OP_CHECKSEQUENCEVERIFY f45d94733d430261962932e0c847075195916a04 OP_CHECKSIG

(note this is not the redeemScript)

There main problem is:

OP_CHECKSIG is looking for a public key, but you have provided a script hash: f45d94733d430261962932e0c847075195916a04. This will never be satisfied so this transaction output is not spendable.

If you want to use the same redeemScript as before, you probably want the following scriptPubKey:

2 OP_CHECKSEQUENCEVERIFY OP_DROP HASH160 f45d94733d430261962932e0c847075195916a04 OP_EQUAL

Note the OP_DROP because the OP_CHECKSEQUENCEVERIFY leaves the 2 on the stack.

In order to spend this, you must provide any signatures and the redeemScript whose hash equals f45d94733d430261962932e0c847075195916a04.

Update:

The redeemScript is still wrong. Instead of 03e8546cfe53ca9014f6a352bc2e5c1f7cec1f5b344c73d4db3ed3b8f075d5c9ef, try 0014e17bbad678e82f8188099a351170c3e0efd4011b. This is the P2WPKH script you used previously in https://tchain.btc.com/46894d9dd5e20147826523b1a3ac8e8c5c64603338430d04bd6f5846af2bb9b4. Also note this is a segwit script so it will look for the signature and pubkey in the witness data: https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki#p2wpkh

Community
  • 1
JBaczuk
  • 7,278
  • 1
  • 11
  • 32
  • Shouldn't that be `OP_DUP OP_HASH160 OP_EQUAL OP_CHECKSIG`? Your example only verifies that the pubkey matches, it does not verify the signature. – Raghav Sood Nov 14 '18 at 15:04
  • I was attempting to provide a `P2SH` example, not a `P2PKH`. – JBaczuk Nov 14 '18 at 15:19
  • Ah, of course, my mistake then! – Raghav Sood Nov 14 '18 at 15:21
  • Please, see my updated post – Andrew Nov 14 '18 at 17:45
  • @Andrew It looks like you're providing a public key `03e8546cfe53ca9014f6a352bc2e5c1f7cec1f5b344c73d4db3ed3b8f075d5c9ef` that doesn't hash to the right value for the `OP_EQUAL` check. You need the `redeemScript` that hashes to `f45d94733d430261962932e0c847075195916a04` – JBaczuk Nov 14 '18 at 18:33
  • What about this transaction? The public key and redeem script is the same, but it's valid tx https://tchain.btc.com/194fe9b2e266b47f51410ceb58f0765551f75bd018e7bfc3439efee14a344777 – Andrew Nov 14 '18 at 18:44
  • That is a witness transaction, and the `redeemScript`is provided in the `scriptSig`: `0014e17bbad678e82f8188099a351170c3e0efd4011b` – JBaczuk Nov 14 '18 at 18:55
  • Can you spend this tx https://tchain.btc.com/46894d9dd5e20147826523b1a3ac8e8c5c64603338430d04bd6f5846af2bb9b4 ? Here is a private key: cUB1iazKDHngknjpTHUfKtH9zNRvHn1aBMPJbK2s913zUegjkeNn – Andrew Nov 14 '18 at 19:47
  • @Andrew see my updated answer – JBaczuk Nov 14 '18 at 22:06
  • Let us [continue this discussion in chat](https://chat.stackexchange.com/rooms/85770/discussion-between-andrew-and-jbaczuk). – Andrew Nov 14 '18 at 22:42
  • Oh my God! I'm so sorry, but I'm not a programmer. I have no idea how to insert redeemscript into transaction and/or how to calculate it. Is there a easy way to just spend this inputs using bitcoin-cli with the folowing private key ? – Andrew Nov 15 '18 at 01:02