1    package it.unisa.dia.gas.crypto.arcanum.fe.rl.w12;
2    
3    import it.unisa.dia.gas.crypto.dfa.DFA;
4    import it.unisa.dia.gas.crypto.dfa.DefaultDFA;
5    import it.unisa.dia.gas.crypto.arcanum.fe.rl.w12.engines.RLW12KEMEngine;
6    import it.unisa.dia.gas.crypto.arcanum.fe.rl.w12.generators.RLW12KeyPairGenerator;
7    import it.unisa.dia.gas.crypto.arcanum.fe.rl.w12.generators.RLW12ParametersGenerator;
8    import it.unisa.dia.gas.crypto.arcanum.fe.rl.w12.generators.RLW12SecretKeyGenerator;
9    import it.unisa.dia.gas.crypto.arcanum.fe.rl.w12.params.*;
10   import it.unisa.dia.gas.crypto.kem.KeyEncapsulationMechanism;
11   import PairingFactory;
12   import org.bouncycastle.crypto.AsymmetricCipherKeyPair;
13   import org.bouncycastle.crypto.CipherParameters;
14   import org.bouncycastle.crypto.InvalidCipherTextException;
15   
16   import java.security.SecureRandom;
17   import java.util.Arrays;
18   
19   import static org.junit.Assert.*;
20   
21   /**
22    * @author Angelo De Caro (arcanumlib@gmail.com)
23    */
24   public class RLW12KEM {
25   
26   
27       public RLW12KEM() {
28       }
29   
30   
31       public AsymmetricCipherKeyPair setup(DFA.Alphabet alphabet) {
32           RLW12KeyPairGenerator setup = new RLW12KeyPairGenerator();
33           setup.init(new RLW12KeyPairGenerationParameters(
34                   new SecureRandom(),
35                   new RLW12ParametersGenerator().init(
36                           PairingFactory.getPairingParameters("params/curves/a.properties"),
37                           alphabet).generateParameters()
38           ));
39           return setup.generateKeyPair();
40       }
41   
42       public byte[][] encaps(CipherParameters publicKey, String w) {
43           try {
44               KeyEncapsulationMechanism kem = new RLW12KEMEngine();
45               kem.init(true, new RLW12EncryptionParameters((RLW12PublicKeyParameters) publicKey, w));
46   
47               byte[] ciphertext = kem.process();
48   
49               assertNotNull(ciphertext);
50               assertNotSame(0, ciphertext.length);
51   
52               byte[] key = Arrays.copyOfRange(ciphertext, 0, kem.getKeyBlockSize());
53               byte[] ct = Arrays.copyOfRange(ciphertext, kem.getKeyBlockSize(), ciphertext.length);
54   
55               return new byte[][]{key, ct};
56           } catch (InvalidCipherTextException e) {
57               e.printStackTrace();
58               fail(e.getMessage());
59           }
60           return null;
61       }
62   
63       public CipherParameters keyGen(CipherParameters publicKey, CipherParameters masterSecretKey, DFA dfa) {
64           RLW12SecretKeyGenerator keyGen = new RLW12SecretKeyGenerator();
65           keyGen.init(new RLW12SecretKeyGenerationParameters(
66                   (RLW12PublicKeyParameters) publicKey,
67                   (RLW12MasterSecretKeyParameters) masterSecretKey,
68                   dfa
69           ));
70   
71           return keyGen.generateKey();
72       }
73   
74       public byte[] decaps(CipherParameters secretKey, byte[] ciphertext) {
75           try {
76               KeyEncapsulationMechanism kem = new RLW12KEMEngine();
77   
78               kem.init(false, secretKey);
79               byte[] key = kem.processBlock(ciphertext);
80   
81               assertNotNull(key);
82               assertNotSame(0, key.length);
83   
84               return key;
85           } catch (InvalidCipherTextException e) {
86               e.printStackTrace();
87               fail(e.getMessage());
88           }
89   
90           return null;
91       }
92   
93   
94       public static void main(String[] args) {
95           DefaultDFA dfa = new DefaultDFA(2);
96           dfa.addFinalState(0);
97           dfa.addTransition(0, '0', 1);
98           dfa.addTransition(0, '1', 0);
99           dfa.addTransition(1, '0', 0);
100          dfa.addTransition(1, '1', 1);
101  
102          DefaultDFA.DefaultAlphabet alphabet = new DefaultDFA.DefaultAlphabet();
103          alphabet.addLetter('0', '1');
104  
105          RLW12KEM rlw12KEM = new RLW12KEM();
106  
107          // setup
108          AsymmetricCipherKeyPair keyPair = rlw12KEM.setup(alphabet);
109  
110          // keygen
111          CipherParameters secretKey = rlw12KEM.keyGen(keyPair.getPublic(), keyPair.getPrivate(), dfa);
112  
113          // Encaps/Decaps for accepting word
114          String w = "00111100";
115          assertTrue(dfa.accept(w));
116          byte[][] ct = rlw12KEM.encaps(keyPair.getPublic(), w);
117          assertEquals(true, Arrays.equals(ct[0], rlw12KEM.decaps(secretKey, ct[1])));
118  
119          // Encaps/Decaps for non-accepting word
120          w = "01111100";
121          assertFalse(dfa.accept(w));
122          ct = rlw12KEM.encaps(keyPair.getPublic(), "01111100");
123          assertEquals(false, Arrays.equals(ct[0], rlw12KEM.decaps(secretKey, ct[1])));
124      }
125  }
126  
127