1    package it.unisa.dia.gas.crypto.arcanum.fe.abe.gghsw13;
2    
3    import it.unisa.dia.gas.crypto.circuit.Circuit;
4    import it.unisa.dia.gas.crypto.circuit.DefaultCircuit;
5    import it.unisa.dia.gas.crypto.arcanum.fe.abe.gghsw13.engines.GGHSW13KEMEngine;
6    import it.unisa.dia.gas.crypto.arcanum.fe.abe.gghsw13.generators.GGHSW13KeyPairGenerator;
7    import it.unisa.dia.gas.crypto.arcanum.fe.abe.gghsw13.generators.GGHSW13ParametersGenerator;
8    import it.unisa.dia.gas.crypto.arcanum.fe.abe.gghsw13.generators.GGHSW13SecretKeyGenerator;
9    import it.unisa.dia.gas.crypto.arcanum.fe.abe.gghsw13.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 it.unisa.dia.gas.crypto.circuit.Circuit.Gate.Type.*;
20   import static it.unisa.dia.gas.crypto.circuit.DefaultCircuit.DefaultGate;
21   import static org.junit.Assert.*;
22   
23   /**
24    * @author Angelo De Caro (arcanumlib@gmail.com)
25    */
26   public class GGHSW13KEM {
27   
28       public GGHSW13KEM() {
29       }
30   
31   
32       public AsymmetricCipherKeyPair setup(int n) {
33           GGHSW13KeyPairGenerator setup = new GGHSW13KeyPairGenerator();
34           setup.init(new GGHSW13KeyPairGenerationParameters(
35                   new SecureRandom(),
36                   new GGHSW13ParametersGenerator().init(
37                           PairingFactory.getPairing("params/mm/ctl13/toy.properties"),
38                           n).generateParameters()
39           ));
40   
41           return setup.generateKeyPair();
42       }
43   
44       public byte[][] encaps(CipherParameters publicKey, String w) {
45           try {
46               KeyEncapsulationMechanism kem = new GGHSW13KEMEngine();
47               kem.init(true, new GGHSW13EncryptionParameters((GGHSW13PublicKeyParameters) publicKey, w));
48   
49               byte[] ciphertext = kem.process();
50   
51               assertNotNull(ciphertext);
52               assertNotSame(0, ciphertext.length);
53   
54               byte[] key = Arrays.copyOfRange(ciphertext, 0, kem.getKeyBlockSize());
55               byte[] ct = Arrays.copyOfRange(ciphertext, kem.getKeyBlockSize(), ciphertext.length);
56   
57               return new byte[][]{key, ct};
58           } catch (InvalidCipherTextException e) {
59               e.printStackTrace();
60               fail(e.getMessage());
61           }
62           return null;
63       }
64   
65       public CipherParameters keyGen(CipherParameters publicKey, CipherParameters masterSecretKey, Circuit circuit) {
66           GGHSW13SecretKeyGenerator keyGen = new GGHSW13SecretKeyGenerator();
67           keyGen.init(new GGHSW13SecretKeyGenerationParameters(
68                   (GGHSW13PublicKeyParameters) publicKey,
69                   (GGHSW13MasterSecretKeyParameters) masterSecretKey,
70                   circuit
71           ));
72   
73           return keyGen.generateKey();
74       }
75   
76       public byte[] decaps(CipherParameters secretKey, byte[] ciphertext) {
77           try {
78               KeyEncapsulationMechanism kem = new GGHSW13KEMEngine();
79   
80               kem.init(false, secretKey);
81               byte[] key = kem.processBlock(ciphertext);
82   
83               assertNotNull(key);
84               assertNotSame(0, key.length);
85   
86               return key;
87           } catch (InvalidCipherTextException e) {
88               e.printStackTrace();
89               fail(e.getMessage());
90           }
91   
92           return null;
93       }
94   
95   
96       public static void main(String[] args) {
97           int n = 4;
98           int q = 3;
99           Circuit circuit = new DefaultCircuit(n, q, 3, new DefaultGate[]{
100                  new DefaultGate(INPUT, 0, 1),
101                  new DefaultGate(INPUT, 1, 1),
102                  new DefaultGate(INPUT, 2, 1),
103                  new DefaultGate(INPUT, 3, 1),
104  
105                  new DefaultGate(AND, 4, 2, new int[]{0, 1}),
106                  new DefaultGate(OR, 5, 2, new int[]{2, 3}),
107  
108                  new DefaultGate(AND, 6, 3, new int[]{4, 5}),
109          });
110  
111          GGHSW13KEM kem = new GGHSW13KEM();
112  
113          // Setup
114          AsymmetricCipherKeyPair keyPair = kem.setup(n);
115  
116          // Keygen
117          CipherParameters secretKey = kem.keyGen(keyPair.getPublic(), keyPair.getPrivate(), circuit);
118  
119          // Encaps/Decaps for satisfying assignment
120          String assignment = "1101";
121          byte[][] ct = kem.encaps(keyPair.getPublic(), assignment);
122          assertEquals(true, Arrays.equals(ct[0], kem.decaps(secretKey, ct[1])));
123  
124          // Encaps/Decaps for not-satisfying assignment
125          assignment = "1001";
126          ct = kem.encaps(keyPair.getPublic(), assignment);
127          assertEquals(false, Arrays.equals(ct[0], kem.decaps(secretKey, ct[1])));
128      }
129  
130  }