Opcodes · crypto · enabled

OP_CHECKDATASIG (0xba)

Checks a signature over arbitrary message data (SHA-256 of msg), not the transaction. It lets contracts verify oracle-signed data. Accepts Schnorr signatures since May 2019.

Verified
Stack in → out
sig msg pubkey → ok
Since
November 2018: CTOR, OP_CHECKDATASIG and the BSV split
Cost
Base instruction cost 100 plus 26,000 per signature check, plus hashing cost for the message (2025 VM limits).
Bitcoin status
Not in Bitcoin (BTC)BTC has no data-signature opcode. In Tapscript, 0xba is OP_CHECKSIGADD (BIP-342), a different operation.

Example

<sig> <msg> <oracle_pubkey> OP_CHECKDATASIG

Step through it opcode by opcode in Bitauth IDE, the in-browser BCH VM debugger.

Sources

  1. BCHN upgrade specs: OP_CHECKDATASIG
  2. Libauth BCH_2023_05 opcodes (bch-2023-opcodes.ts)
  3. BIP-342: Validation of Taproot Scripts