private byte[]? DecryptApplePayData(byte[] keyMaterial, ApplePayPaymentToken token)
{
try
{
if (token.PaymentData?.Data == null)
{
throw new InvalidOperationException("Required payment data was not found on Payment Token JSON.");
}
return(ApplePayHelper.DecryptCipherDataUsingAesGcmAlgorithm(keyMaterial, Convert.FromBase64String(token.PaymentData.Data)));
}
catch (Exception keyDerivationException)
{
MessageBox.Show(
$"Apple Pay decryption failed:\r\n\r\n{keyDerivationException}",
"Apple Pay Key Decryption Failure",
MessageBoxButtons.OK,
MessageBoxIcon.Error);
return(null);
}
}
private bool VerifyApplePayPaymentProcessingCertificate(X509Certificate2 paymentProcessingCertificate, ApplePayPaymentToken token)
{
try
{
if (token.PaymentData?.Header?.PublicKeyHash == null)
{
throw new InvalidOperationException("Required header data was not found on Payment Token JSON.");
}
ApplePayHelper.ValidatePaymentProcessingCertificate(
paymentProcessingCertificate,
token.PaymentData.Header.PublicKeyHash);
return(true);
}
catch (Exception paymentProcessingCertificateException)
{
MessageBox.Show(
$"Payment Processing Certificate validation failed:\r\n\r\n{paymentProcessingCertificateException}",
"Apple Pay Payment Processing Certificate Failure",
MessageBoxButtons.OK,
MessageBoxIcon.Error);
return(false);
}
}
private byte[]? DeriveApplePayKeyMaterial(X509Certificate2 paymentProcessingCertificate, ApplePayPaymentToken token)
{
try
{
if (token.PaymentData?.Header?.EphemeralPublicKey == null)
{
throw new InvalidOperationException("Required header data was not found on Payment Token JSON.");
}
return(ApplePayHelper.DeriveKeyMaterialUsingEllipticCurveDiffieHellmanAlgorithm(
paymentProcessingCertificate,
token.PaymentData.Header.EphemeralPublicKey));
}
catch (Exception keyDerivationException)
{
MessageBox.Show(
$"Apple Pay key derivation failed:\r\n\r\n{keyDerivationException}",
"Apple Pay Key Derivation Failure",
MessageBoxButtons.OK,
MessageBoxIcon.Error);
return(null);
}
}
private bool VerifyApplePaySignature(X509Certificate2 rootCertificateAuthority, ApplePayPaymentToken token)
{
try
{
if (token.PaymentData?.Signature == null ||
token.PaymentData?.Data == null ||
token.PaymentData?.Header?.EphemeralPublicKey == null ||
token.PaymentData?.Header?.TransactionId == null)
{
throw new InvalidOperationException("Required signature data was not found on Payment Token JSON.");
}
ApplePayHelper.VerifyApplePaySignature(
rootCertificateAuthority,
token.PaymentData.Signature,
token.PaymentData.Data,
token.PaymentData.Header.EphemeralPublicKey,
token.PaymentData.Header.TransactionId.ToByteArray(),
token.PaymentData.Header.ApplicationData?.ToByteArray(),
_ValidateSigningTimeCheckBox.Checked ? 300 : (int?)null);
return(true);
}
catch (Exception signatureValidationException)
{
MessageBox.Show(
$"Payment Token Signature validation failed:\r\n\r\n{signatureValidationException}",
"Apple Pay Signature Verification Failure",
MessageBoxButtons.OK,
MessageBoxIcon.Error);
return(false);
}
}