question: public static CertificateID createCertId ( BigInteger subjectSerialNumber , X509Certificate issuer ) throws Exception { return new CertificateID ( createDigestCalculator ( SHA1_ID ) , new X509CertificateHolder ( issuer . getEncoded ( ) ) , subjectSerialNumber ) ; }
target:  Creates a new certificate ID instance (using SHA-1 digest calculator) for the specified subject certificate serial number and issuer certificate.