01 - Pay to Public Key (P2PK)

Pay to Public Key is the most simple script that can be deployed that uses the security of Elliptic curve signatures to lock transaction outputs.

A pay to public key script is defined as follows:

<public_key> OP_CHECKSIG

To spend an output that is locked with a P2PK script, the following solution is provided:

<signature>

The validation engine will evaluate the full script as follows:

<signature> <public_key> OP_CHECKSIG

For the purposes of brevity, we exclude the pushdata opcodes and use | | to represent the OP_CODESEPARATOR that the validation engine automatically inserts inbetween the input and output scripts.

A breakdown of the script evaluation process is shown below:

Stack	Script	Description
Empty.	<sig> | | <pubKey> OP_CHECKSIG	scriptSig and scriptPubKey are combined.
<sig>	<pubKey> OP_CHECKSIG	Signature is added to the stack.
<sig> <pubKey>	OP_CHECKSIG	Pubkey is added to stack.
true	Empty.	Signature is checked against the public key

As shown above, the signature and public key are pushed onto the stack, and then consumed by OP_CHECKSIG which leaves the result of the check on the stack. If the signature is valid, the input can be spent in the transaction.