EncryptedTimeStamp encryptedTimeStamp = new EncryptedTimeStamp( timeStamp, 0 );
EncryptionKey clientKey = getEncryptionKey( clientPrincipal, passPhrase );
EncryptedData encryptedData = lockBox.seal( clientKey, encryptedTimeStamp, KeyUsage.NUMBER1 );
byte[] encodedEncryptedData = EncryptedDataEncoder.encode( encryptedData );
PaData preAuth = new PaData();
preAuth.setPaDataType( PaDataType.PA_PK_AS_REQ );