question: public ISO9796d2PSSSigner ( AsymmetricBlockCipher cipher , Digest digest , int saltLength , boolean implicit ) { this . cipher = cipher ; this . digest = digest ; this . hLen = digest . getDigestSize ( ) ; this . saltLength = saltLength ; if ( implicit ) { trailer = TRAILER_IMPLICIT ; } else { Integer trailerObj = ( Integer ) trailerMap . get ( digest . getAlgorithmName ( ) ) ; if ( trailerObj != null ) { trailer = trailerObj . intValue ( ) ; } else { throw new IllegalArgumentException ( "no valid trailer for digest" ) ; } } }
target:  Generate a signer for the with either implicit or explicit trailers for ISO9796-2, scheme 2 or 3.