hash_signature_for_input

exampl.cr

def hash_signature_for_input(input_idx : Int32) : String
  
  buffer = IO::Memory.new
        
  # 1. Version
  buffer.write_bytes(ver, IO::ByteFormat::LittleEndian)
  
  # 2. Inputs
  Transaction.write_var_int(buffer, inputs.size.to_u64)
  inputs[input_idx].to_buffer(buffer)
  
  # 3. Outputs
  Transaction.write_var_int(buffer, outputs.size.to_u64)
  outputs.each do |output|
    output.to_buffer(buffer)
  end
  
  # 4. Lock time
  buffer.write_bytes(lock_time, IO::ByteFormat::LittleEndian)
  
  # 5. Hash type = 1 for SIG_HASH_ALL
  buffer.write_bytes(1.to_u32, IO::ByteFormat::LittleEndian)
  
  
  hash = OpenSSL::Digest.new("SHA256")
  hash.update(buffer.to_slice)
  hash1 = hash.digest
  
  hash = OpenSSL::Digest.new("SHA256")
  hash.update(hash1)
  hash2 = hash.digest
  
  return OnChain.to_hex(hash2)
end