verify method
Verify the certificate
Implementation
void verify(X509 issuer) {
final now = DateTime.now();
if (now.compareTo(notAfter) > 0) {
throw Exception('Certificate expired: $notAfter');
}
if (now.compareTo(notBefore) < 0) {
throw Exception('Certificate not yet valid: $notBefore');
}
issuer.verifySignature(
signatureValue,
body,
digestAlgorithm,
);
}