public byte[] getDecryptionCipherKey() {
        return decryptionCipherKey;
    }
Returns the decryption cipher key to use for decryption operations.

@return the cipher key to use for decryption operations.
@see #setCipherService for a description of the various {@code get/set*Key} methods.
core/src/main/java/org/apache/shiro/mgt/AbstractRememberMeManager.java