Certificate ::= SEQUENCE {
     version [0] EXPLICIT Version DEFAULT v1,
     serialNumber CertificateSerialNumber,
     signature AlgorithmIdentifier,
     issuer Name,
     validity Validity,
     subject Name,
     subjectPublicKeyInfo SubjectPublicKeyInfo,
     issuerUniqueID [1] IMPLICIT UniqueIdentifier OPTIONAL,
     subjectUniqueID [2] IMPLICIT UniqueIdentifier OPTIONAL,
     extensions [3] EXPLICIT Extensions OPTIONAL
