code: public static CertifyingSigner getInstance(boolean forSigning, CertifiedKeyPair certifier, SignerFactory factory)
      {
          return new CertifyingSigner(certifier.getCertificate(),
              factory.getInstance(forSigning, certifier.getPrivateKey()));
      }
docs: Get a certifying signer instance from the given signer factory for a given certifier.
  
  @param forSigning true for signing, and false for verifying.
  @param certifier the certified key pair of the certifier.
  @param factory a signer factory to create the signer.
  @return a certifying signer.