Opcode Explained

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OP_EQUALVERIFY ​

INFO

Opcode number: 136
Byte representation: 0x88
Short description: Compare the top two items on the stack and halts the script if they are not equal.

OP_EQUALVERIFY combines the functionality of OP_EQUAL and OP_VERIFY. It compares the top two items on the stack and removes them. If they are equal, the script continues execution. If they are not equal, the script fails immediately. This opcode is commonly used in scripts to ensure that two values match without leaving a true or false result on the stack.

Operation ​

  1. Compare the top two items on the stack.
  2. If the items are equal, remove them from the stack and continue the script.
  3. If the items are not equal, the script fails.

Notes ​

  • OP_EQUALVERIFY is frequently used in Pay-to-PubKeyHash (P2PKH) scripts, where it ensures the provided public key hash matches the expected hash.
  • Unlike OP_EQUAL, OP_EQUALVERIFY does not leave a result (true or false) on the stack. Instead, it either allows the script to continue or fails immediately.

Examples ​

Example 1 ​

Using OP_EQUALVERIFY to check equality:

shell
# ASM script
OP_7 OP_7 OP_EQUALVERIFY

# Raw script
575788

# Stack (before OP_EQUALVERIFY)
7
7

# Stack (after OP_EQUALVERIFY)
(empty stack)  # items removed, script continues

Example 2 ​

Using OP_EQUALVERIFY with unequal items:

shell
# ASM script
OP_1 OP_2 OP_EQUALVERIFY

# Raw script
515288

# Stack (before OP_EQUALVERIFY)
2  # top
1

# Stack (after OP_EQUALVERIFY)
# Script fails immediately due to inequality

Common Usage: Pay to Public Key Hash (P2PKH) ​

In P2PKH scripts, OP_EQUALVERIFY is used to ensure the provided public key hash matches the expected hash:

shell
# ASM script for P2PKH
OP_DUP OP_HASH160 <PubKeyHash> OP_EQUALVERIFY OP_CHECKSIG

Here, OP_EQUALVERIFY confirms that the hash of the provided public key matches the expected PubKeyHash. If they match, the script continues to OP_CHECKSIG; otherwise, it fails.