问如何在我的“第三方服务器”上验证GKLocalPlayer？

EN

# iOS Game Center verifier for 3rd party game servers written in Ruby.
#
# *** Credits ***
#   Based off of code and comments at https://stackoverflow.com/questions/17408729/how-to-authenticate-the-gklocalplayer-on-my-third-party-server
#
# *** Improvements ***
#   This version uses Ruby's built in HTTP client instead of a 3rd party gem.
#   It's updated to use SHA256 instead of SHA1.
#   It Base64 decodes the salt and signature.  If your client or server already does this then you will need to remove the calls to Base64.decode64().
#   It validates that the public key URL is from apple.com.
#   It has been tested with Apple's Game Center's sandbox public key URL (https://sandbox.gc.apple.com/public-key/gc-sb-2.cer) and works as of June 24th, 2015.
#
# *** Notes on public key certificate validation ***
#   You will need the correct code signing CA to verify the certificate returned from the pubic key URL.
#   You can download/verify the CA certificate here: https://knowledge.symantec.com/support/code-signing-support/index?page=content&actp=CROSSLINK&id=AR2170
#   I have embedded the CA certificate for convenience so that you don't need to save it to your filesystem.
#   When the public key URL changes in the future, you may need to update the text in the ca_certificate_text() method.
#
# *** Usage ***
#   verified, reason = GameCenterVerifier.verify(...)

class GameCenterVerifier
  # Verify that user provided Game Center data is valid.
  # False will be returned along with a reason if any validations fail.
  # Otherwise, it will return true and a nil reason if all validations pass.
  def self.verify(game_center_id, public_key_url, timestamp, salt, signature, bundle_id)
    salt = Base64.decode64(salt)
    signature = Base64.decode64(signature)
    payload = game_center_id.encode('UTF-8') + bundle_id.encode('UTF-8') + [timestamp.to_i].pack('Q>') + salt
    pkey_certificate = get_public_key_certificate(public_key_url)
    return false, 'Invalid public key url' unless public_key_url_is_valid?(public_key_url)
    return false, 'Invalid public key certificate' unless public_key_certificate_is_valid?(pkey_certificate)
    return false, 'OpenSSL errors (before signature check)' unless OpenSSL.errors.empty?
    return false, 'Invalid signature' unless signature_is_valid?(pkey_certificate, signature, payload)
    return false, 'OpenSSL errors (after signature check)' unless OpenSSL.errors.empty?
    return true, nil
  end

  private

  def self.get_public_key_certificate(url)
    uri = URI.parse(url)
    http = Net::HTTP.new(uri.host, uri.port)
    request = Net::HTTP::Get.new(uri.request_uri)
    http.use_ssl = true
    http.open_timeout = 5
    http.read_timeout = 5
    cert = http.request(request).body
    OpenSSL::X509::Certificate.new(cert)
  end

  def self.public_key_url_is_valid?(public_key_url)
    uri = URI(public_key_url)
    tokens = uri.host.split('.')
    return false if uri.scheme != 'https'
    return false if tokens[-1] != 'com' || tokens[-2] != 'apple'
    true
  end

  def self.public_key_certificate_is_valid?(pkey_cert)
    pkey_cert.verify(get_ca_certificate.public_key)
  end

  def self.signature_is_valid?(pkey_cert, signature, payload)
    pkey_cert.public_key.verify(OpenSSL::Digest::SHA256.new, signature, payload)
  end

  def self.get_ca_certificate
    OpenSSL::X509::Certificate.new(ca_certificate_text)
  end

  def self.ca_certificate_text
    data = <<EOF
-----BEGIN CERTIFICATE-----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n0thlV8ccO4XfduL5WGJeMdoG68ReBqYrsRVR1PZszLWoQ5GQMWXkorRU6eZW4U1
V9Pqk2JhIArHMHckEU1ig7a6e2iCMe5lyt/51Y2yNdyMK29qclxghJzyDJRewFZS
AEjM0/ilfd4v1xPkOKiE1Ua4E4bCG53qWjjdm9sCAwEAAaOCAYMwggF/MC8GCCsG
AQUFBwEBBCMwITAfBggrBgEFBQcwAYYTaHR0cDovL3MyLnN5bWNiLmNvbTASBgNV
HRMBAf8ECDAGAQH/AgEAMGwGA1UdIARlMGMwYQYLYIZIAYb4RQEHFwMwUjAmBggr
BgEFBQcCARYaaHR0cDovL3d3dy5zeW1hdXRoLmNvbS9jcHMwKAYIKwYBBQUHAgIw
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cZXHZVqnjjDSRFph23Bv2iEFwi5zuknx0ZP+XcnNXgPgiZ4/dB7X9ziLqdbPuzUv
M1ioklbRyE07guZ5hBb8KLCxR/Mdoj7uh9mmf6RWpT+thC4p3ny8qKqjPQQB6rqT
og5QIikXTIfkOhFf1qQliZsFay+0yQFMJ3sLrBkFIqBgFT/ayftNTI/7cmd3/SeU
x7o1DohJ/o39KK9KEr0Ns5cF3kQMFfo2KwPcwVAB8aERXRTl4r0nS1S+K4ReD6bD
dAUK75fDiSKxH3fzvc1D1PFMqT+1i4SvZPLQFCE=
-----END CERTIFICATE-----
EOF
  end
end