PaEncTsEnc encryptedTimeStamp = new PaEncTsEnc( timeStamp, 0 );
EncryptionKey clientKey = getEncryptionKey( clientPrincipal, passPhrase, config.getEncryptionTypes() );
EncryptedData encryptedData = lockBox.seal( clientKey, encryptedTimeStamp,
KeyUsage.AS_REQ_PA_ENC_TIMESTAMP_WITH_CKEY );
ByteBuffer buffer = ByteBuffer.allocate( encryptedData.computeLength() );
byte[] encodedEncryptedData = encryptedData.encode( buffer ).array();
PaData preAuth = new PaData();
preAuth.setPaDataType( PaDataType.PA_PK_AS_REQ );
preAuth.setPaDataValue( encodedEncryptedData );