Question

I need 2 simple encryption and decryption methods to encrypt a String a in an ecrypted String b using another String key as Encryption and Decryption key.

I have found this code that seems doing what I need

public class DesEncrypter {
    Cipher ecipher;
    Cipher dcipher;

    DesEncrypter(SecretKey key) {
        try {
            ecipher = Cipher.getInstance("DES");
            dcipher = Cipher.getInstance("DES");
            ecipher.init(Cipher.ENCRYPT_MODE, key);
            dcipher.init(Cipher.DECRYPT_MODE, key);

        } catch (javax.crypto.NoSuchPaddingException e) {
        } catch (java.security.NoSuchAlgorithmException e) {
        } catch (java.security.InvalidKeyException e) {
        }
    }

    public String encrypt(String str) {
        try {
            // Encode the string into bytes using utf-8
            byte[] utf8 = str.getBytes("UTF8");

            // Encrypt
            byte[] enc = ecipher.doFinal(utf8);

            // Encode bytes to base64 to get a string
            return new sun.misc.BASE64Encoder().encode(enc);
        } catch (javax.crypto.BadPaddingException e) {
        } catch (IllegalBlockSizeException e) {
        } catch (UnsupportedEncodingException e) {
        } catch (java.io.IOException e) {
        }
        return null;
    }

    public String decrypt(String str) {
        try {
            // Decode base64 to get bytes
            byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);

            // Decrypt
            byte[] utf8 = dcipher.doFinal(dec);

            // Decode using utf-8
            return new String(utf8, "UTF8");
        } catch (javax.crypto.BadPaddingException e) {
        } catch (IllegalBlockSizeException e) {
        } catch (UnsupportedEncodingException e) {
        } catch (java.io.IOException e) {
        }
        return null;
    }
}

Unfortunately need a fix to works,
I get an error in

sun.misc.BASE64Encoder()

and in

sun.misc.BASE64Decoder()

that ask me to create a base64 encoder and decoder in sun.misc package

How to fix?

Answer 1

sun.misc.BASE64Encoder and sun.misc.BASE64Decoder do not exist in the Android Java implementation. They are internal only in Oracle’s JDK, although you do have access, they are not guaranteed to be there.

You can use the android.util.Base64 class to encode and decode base 64 in Android.

To encode, change:

return new sun.misc.BASE64Encoder().encode(enc);

to:

return android.util.Base64.encodeToString(enc, android.util.Base64.DEFAULT);

To decode, change:

byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);

to:

byte[] dec = android.util.Base64.decode(str, android.util.Base64.DEFAULT);