Covenants++ Opcodes

Kaspa’s covenant related opcodes enable introspection and other necessary script features. These have been added through KIP-10 and KIP-17.

Opcode	Hex	Notes
OpBlake2bWithKey	0xa7	Pops 2 items off the stack - `key` and `data`. Creates a 32 byte keyed hash using blake2b. Pushes the hash onto the stack.
OpTxVersion	0xb2	Pushes the transaction’s version onto the stack.
OpTxInputCount	0xb3	Pushes number of transaction inputs onto the stack.
OpTxOutputCount	0xb4	Pushes number of transaction outputs onto the stack.
OpTxLockTime	0xb5	Pushes the transaction’s lock time onto the stack.
OpTxSubnetId	0xb6	Pushes the transaction’s subnetwork ID onto the stack.
OpTxGas	0xb7	Pushes the transaction’s gas onto the stack.
OpTxPayloadSubstr	0xb8	Pops 2 items off the stack - `start` and `end`. Pushes the substring of payload from `start` to `end` onto the stack.
OpTxInputIndex	0xb9	Pushes this transaction input’s index onto the stack.
OpOutpointTxId	0xba	Pops 1 item off the stack as `idx`. Of the input at `idx`, pushes the previous outpoint’s transaction ID onto the stack.
OpOutpointIndex	0xbb	Pops 1 item off the stack as `idx`. Of the input at `idx`, pushes the previous outpoint’s index onto the stack.
OpTxInputScriptSigSubstr	0xbc	Pops 3 items off the stack - `idx`, `start`, and `end`. Of the input at `idx`, pushes the substring of `signature_script` from `start` to `end` onto the stack.
OpTxInputSeq	0xbd	Pops 1 item off the stack as `idx`. Of the input at `idx`, pushes the sequence field as little-endian bytes onto the stack.
OpTxInputAmount	0xbe	Pops 1 item off the stack as `idx`. Of the input at `idx`, pushes the UTXO’s amount onto the stack.
OpTxInputSpk	0xbf	Pops 1 item off the stack as `idx`. Of the input at `idx`, pushes the UTXO’s script public key (including version prefix) onto the stack.
OpTxInputDaaScore	0xc0	Pops 1 item off the stack as `idx`. Of the input at `idx`, pushes the UTXO’s DAA score onto the stack.
OpTxInputIsCoinbase	0xc1	Pops 1 item off the stack as `idx`. Of the input at `idx`, pushes the UTXO’s is coinbase flag onto the stack.
OpTxOutputAmount	0xc2	Pops 1 item off the stack as `idx`. Of the output at `idx`, pushes the output’s value (amount) onto the stack.
OpTxOutputSpk	0xc3	Pops 1 item off the stack as `idx`. Of the output at `idx`, pushes the output’s value script public key (including version prefix) onto the stack.
OpTxPayloadLen	0xc4	Pushes the transaction’s payload length onto the stack.
OpTxInputSpkLen	0xc5	Pops 1 item off the stack as `idx`. Of the input at `idx`, pushes the script public key’s byte length (including version prefix) onto the stack.
OpTxInputSpkSubstr	0xc6	Pops 3 items off the stack - `idx`, `start`, and `end`. Of the input at `idx`, pushes the substring of the UTXO’s script public key from `start` to `end` onto the stack.
OpTxOutputSpkLen	0xc7	Pops 1 item off the stack as `idx`. Of the output at `idx`, pushes the script public key’s bytes length (including version prefix) onto the stack.
OpTxOutputSpkSubstr	0xc8	Pops 3 items off the stack - `idx`, `start`, and `end`. Of the output at `idx`, pushes the substring of the script public key from `start` to `end` onto the stack.
OpTxInputScriptSigLen	0xc9	Pops 1 item off the stack as `idx`. Of the input at `idx`, pushes the signature script’s length onto the stack.
OpAuthOutputCount	0xcb	Pops 1 item off the stack as `input_idx`. Of the input at `input_idx`, pushes the number of outputs authorized via covenant binding onto the stack.
OpAuthOutputIdx	0xcc	Pops 2 items off the stack - `input_idx` and `k`. Finds the `k`-th output that has a covenant binding pointing to the input at `input_idx`. Pushes the output’s actual index onto the stack.
OpNum2Bin	0xcd	Pops 2 items off the stack, treating values as `size` and `num`. `size` must be at most 8 bytes. Serializes `num` into exactly `size` bytes.
OpBin2Num	0xce	Pops 1 item off the stack, deserializes it as an i64, and pushes it back onto the stack as minimally encoded bytes.
OpInputCovenantId	0xcf	Pops 1 item off the stack as `idx`. Of the input at `idx`, pushes the UTXO’s covenant ID onto the stack, or an empty byte vector if the UTXO does not have a covenant ID.
OpCovInputCount	0xd0	Pops 1 item off the stack as `covenant_id`. Pushes the number of inputs with this covenant id onto the stack.
OpCovInputIdx	0xd1	Pops 2 items off the stack - `k` and `covenant_id`. Finds the `k`-th transaction input with `covenant_id` and pushes the input’s actual index onto the stack.
OpCovOutCount	0xd2	Pops 1 item off the stack as `covenant_id`. Pushes the number of outputs with this covenant id onto the stack.
OpCovOutputIdx	0xd3	Pops 2 items off the stack - `k` and `covenant_id`. Finds the `k`-th transaction output with `covenant_id` and pushes the output’s actual index onto the stack.
OpChainblockSeqCommit	0xd4	Pops 1 item off the stack as `block` (32 byte block hash). Checks if `block` is a chain block from the POV of the current selected parent. If `block` has been pruned, is not a chain block, is from pre-covenant activation, or is beyond an allowed depth (currently finality depth), a script error is raised. The `block`’s accepted ID merkle root is retrieved and pushed onto the stack as the sequence commitment.