defmodule BitcoinLib.Script.Opcodes.Crypto.Sha256 do
@moduledoc """
Based on https://en.bitcoin.it/wiki/Script
Word OP_SHA256
Opcode 168
Hex 0xa8
Input in
Output hash
The input is hashed using SHA-256.
"""
@behaviour BitcoinLib.Script.Opcode
defstruct []
alias BitcoinLib.Crypto
alias BitcoinLib.Script.Opcodes.Crypto.Sha256
@type t :: Sha256
@value 0xA8
@doc """
Returns 0xa8
## Examples
iex> BitcoinLib.Script.Opcodes.Crypto.Sha256.v()
0xa8
"""
@spec v() :: 0xA8
def v do
@value
end
@doc """
Returns <<0xa8>>
## Examples
iex> BitcoinLib.Script.Opcodes.Crypto.Sha256.encode()
<<0xa8>>
"""
@spec encode() :: <<_::8>>
def encode() do
<<@value::8>>
end
@doc """
The input is hashed using SHA-256.
## Examples
iex> pub_key = <<0x0218fb7aff2c6cb9c25b7cd9aa0b9bdd712e5617f07cb0c96bdda0b44c25a5d25f::264>>
...> %BitcoinLib.Script.Opcodes.Crypto.Sha256{}
...> |> BitcoinLib.Script.Opcodes.Crypto.Sha256.execute([pub_key, 3])
{:ok, [<<0x01e9a3394b9fdf95aa04dcb91bf540aae4196bf8c550d9be4c2d0ff94fd505bd::256>>, 3]}
"""
@spec execute(Sha256.t(), [<<_::264>> | list()]) :: {:ok, [<<_::256>> | list()]}
def execute(_opcode, []), do: {:error, "trying to execute OP_SHA256 on an empty stack"}
def execute(_opcode, [first_element | remaining]) do
hash = Crypto.sha256(first_element)
{:ok, [hash | remaining]}
end
end