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1Manual implementation of 3DES (academic)
2KeyGenerator kgen = KeyGenerator.getInstance("DES");
3        SecretKey sk_1 = kgen.generateKey(); 
4        SecretKey sk_2 = kgen.generateKey();
5        byte[] raw_1 = sk_1.getEncoded();
6        byte[] raw_2 = sk_2.getEncoded();
7
8        spec_1 = new SecretKeySpec(raw_1, "DES"); //key 1
9        spec_2 = new SecretKeySpec(raw_2, "DES"); //key 2
10
11        cipher = Cipher.getInstance("DES"); //standard mode is ECB which is block-by-block w/PKCS5Padding
12        cipher2 = Cipher.getInstance("DES");
13
14
15    protected byte[] get3DESEncryption(byte[] plaintext) throws Exception{
16        byte[] output = new byte[plaintext.length];
17        System.out.println("output len init: " + output.length);
18        cipher.init(Cipher.ENCRYPT_MODE, spec_1);
19        cipher2.init(Cipher.DECRYPT_MODE, spec_2);
20
21        //first encryption round, key 1 used
22        output = cipher.doFinal(plaintext);
23        //second "encryption" round, key 2 used but decrypt run
24        output = cipher2.doFinal(output);
25        //third encryption round, key 1 used
26        output = cipher.doFinal(output);
27
28        //return ciphertext
29        return output;
30    }