Operation not valid with the current stack size

According to bip65 https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki

I can use expressions like IF ... ELSE ... ENDIF Here is example script from this document:

IF
    HASH160 <Hash160(encryption key)> EQUALVERIFY
    <publisher pubkey> CHECKSIG
ELSE
    <expiry time> CHECKLOCKTIMEVERIFY DROP
    <buyer pubkey> CHECKSIG
ENDIF

But when I trying to spend transaction with the following script:

OP_IF 
    OP_SHA256 4bf5122f344554c53bde2ebb8cd2b7e3d1600ad631c385a5d7cce23c7785459a OP_EQUAL 
OP_ELSE 
    10 OP_CHECKLOCKTIMEVERIFY OP_DROP OP_SHA256 dbc1b4c900ffe48d575b5da5c638040125f65db0fe3e24494b76ea986457d986 OP_EQUAL
OP_ENDIF

https://tchain.btc.com/dbf477b700b7e159c07f15e1b6f5917e1247175e055fe533068a6fbc4ce2c374

I get error:

bitcoin-cli -testnet sendrawtransaction 020000000174c3e24cbc6f8a0633e55f055e1747127e91f5b6e1157fc059e1b700b777f4db000000000151ffffffff01c0d401000000000023a820dbc1b4c900ffe48d575b5da5c638040125f65db0fe3e24494b76ea986457d9868700000000
error code: -26
error message:
mandatory-script-verify-flag-failed (Operation not valid with the current stack size) (code 16)

Where is my error ?

P.S.

SHA256 from 1 -> 4bf5122f344554c53bde2ebb8cd2b7e3d1600ad631c385a5d7cce23c7785459a

SHA256 from 2 -> dbc1b4c900ffe48d575b5da5c638040125f65db0fe3e24494b76ea986457d986

Andrew

Posted 2018-12-07T20:08:44.607

Reputation: 161

Answers

Your transaction only has 0x51 (just OP_1) in its scriptsig, the OP_IF consumes the 1, and OP_SHA256 then operates on an empty stack, causing this error.

arubi

Posted 2018-12-07T20:08:44.607

Reputation: 1 460

Like arubi said, you're scriptSig is just 0x51:

$ bitcoin-cli decoderawtransaction 020000000174c3e24cbc6f8a0633e55f055e1747127e91f5b6e1157fc059e1b700b777f4db000000000151ffffffff01c0d401000000000023a820dbc1b4c900ffe48d575b5da5c638040125f65db0fe3e24494b76ea986457d9868700000000
{
  "txid": "2e7c6efc9dc6104f132a10d0d64263269d1ece326b4d64cb1061fe5a81b4d53b",
  "hash": "2e7c6efc9dc6104f132a10d0d64263269d1ece326b4d64cb1061fe5a81b4d53b",
  "version": 2,
  "size": 96,
  "vsize": 96,
  "weight": 384,
  "locktime": 0,
  "vin": [
    {
      "txid": "dbf477b700b7e159c07f15e1b6f5917e1247175e055fe533068a6fbc4ce2c374",
      "vout": 0,
      "scriptSig": {
        "asm": "1",
        "hex": "51"
      },
      "sequence": 4294967295
    }
  ],
  "vout": [
    {
      "value": 0.00120000,
      "n": 0,
      "scriptPubKey": {
        "asm": "OP_SHA256 dbc1b4c900ffe48d575b5da5c638040125f65db0fe3e24494b76ea986457d986 OP_EQUAL",
        "hex": "a820dbc1b4c900ffe48d575b5da5c638040125f65db0fe3e24494b76ea986457d98687",
        "type": "nonstandard"
      }
    }
  ]
}

This means if the scriptPubKey of the input you're spending is:

OP_IF 
    OP_SHA256 4bf5122f344554c53bde2ebb8cd2b7e3d1600ad631c385a5d7cce23c7785459a OP_EQUAL 
OP_ELSE 
    10 OP_CHECKLOCKTIMEVERIFY OP_DROP OP_SHA256 dbc1b4c900ffe48d575b5da5c638040125f65db0fe3e24494b76ea986457d986 OP_EQUAL
OP_ENDIF

It will execute this branch (since the top stack element is true):

OP_IF 
    OP_SHA256 4bf5122f344554c53bde2ebb8cd2b7e3d1600ad631c385a5d7cce23c7785459a OP_EQUAL

You must also provide whatever hashes to the value 4bf5122f344554c53bde2ebb8cd2b7e3d1600ad631c385a5d7cce23c7785459a in order for it to return successfully.

JBaczuk

Posted 2018-12-07T20:08:44.607

Reputation: 6 172