Peach Webhook Decrypter

readme.md

Usage

Peach payments encrypts their webhook payload, so you'll need to decrypt it in order to do any sort of business logic with the notification.

decoder = PeachPayments::Decoder.new(
  body: params[:encryptedBody], # This param is correct, don't change it
  iv: request.headers["HTTP_X_INITIALIZATION_VECTOR"],
  auth_tag: request.headers["HTTP_X_AUTHENTICATION_TAG"]
  key: "some_super_secret_key" # when you create a webhook with peach, they will give you the decryption key as well
)
decoded_response = decoder.decode # a hash will be returned

# fancy business logic here ...

decoder.rb

class PeachPayments::Decoder
  def initialize(body:, auth_tag:, iv:, key:)
    @body = body
    @key = key
    @auth_tag = auth_tag
    @iv = iv
  end

  def decode
    packed_key, packed_iv, packed_auth_tag, packed_body = *[
      @key,
      @iv,
      @auth_tag,
      @body
    ].map do |value|
      [value].pack("H*")
    end

    decipher = OpenSSL::Cipher.new("aes-256-gcm").tap do |cipher|
      cipher.decrypt
      cipher.key = packed_key
      cipher.iv = packed_iv
      cipher.auth_tag = packed_auth_tag
    end
    JSON.parse(decipher.update(packed_body) + decipher.final, symbolize_names: true)
  rescue # I don't really care what exceptions are thrown, but you can modify it for your usecase.
    {}
  end
end