import javax.crypto.*; import java.security.KeyFactory; import java.security.Key; import java.security.spec.X509EncodedKeySpec; import java.security.GeneralSecurityException; import java.security.InvalidKeyException; import java.security.spec.InvalidKeySpecException; import java.security.NoSuchAlgorithmException; import java.security.InvalidAlgorithmParameterException; import java.security.spec.Al