Bitcoin: If no push opcode, how does item still end up on stack (tx verification)

Push Op Code: Understanding the Mechanics of Bitcoin Transactions

Bitcoin transactions are processed on the network and verified by nodes using complex algorithms. One of these algorithms is the push op code, which plays a key role in the transaction verification process. In this article, we will dive into how the push op code works and why it is so important to put an item on the stack (confirm a transaction).

What is a push opcode?

A push opcode is a protocol that Bitcoin nodes use to verify transactions. It is an optimization method that reduces the computational cost of verifying transactions. Simply put, a push opcode allows nodes to push data directly onto the stack, without reading it from disk or memory.

How ​​does a push opcode work?

When a new transaction is created, the sender (Alice) sends it to the network along with her public key and signature. The recipient (Bob) receives the transaction, verifies its authenticity, and includes it in their transaction. To verify this transaction, Bob’s node reads all the necessary data from disk or memory, including Alice’s public key script, public key hash, signature, etc.

This process uses the push operation code. Here is a detailed description:

• Public key script insertion

  

  : The sender inserts Alice’s public key script onto the stack.

• Public key hash push: In response, Bob pushes his public key hash onto the stack.

• Signature data push: Bob also pushes the signing data from his private key onto the stack.

Why does this happen?

To successfully verify a transaction, nodes must process all the necessary data in memory or disk. By placing these components directly on the stack, nodes can avoid having to load them into memory or disk each time they are needed.

In particular, direct opcodes are useful for verifying transactions that use multiple public keys, signatures, and other data elements. This reduces the burden of verifying transactions, making them faster and more efficient.

Example: Alice’s transaction

Let’s say Alice wants to send 10 bitcoins to Bob. Her transaction would look like this:

0x00 01 02 03 04 05 06 07 08 09 10 11 12
| (unsigned integer) | (public key script) |

When Alice sends this transaction, her node uses the push opcode to push the following data onto the stack:

• Alice’s public key hash (0x1234567890abcdef)

• Bob’s public key hash (0x234567890abcddef)

Bob’s node reads these values ​​from disk or memory and verifies them as part of the transaction validation process.

Application

In summary, the push opcode is a clever optimization technique that reduces the computational burden of Bitcoin transactions. By putting public keys, signatures, and other data elements directly on the stack, nodes can verify transactions efficiently and effectively. This optimization enables faster and more efficient network operations, making it a core part of the Bitcoin protocol.

I hope this article helped you understand how the push operation code works and why it is very important to get the element on the stack (confirm the operation).