1package eu.siacs.conversations.utils;
2
3import java.math.BigInteger;
4import java.nio.charset.Charset;
5import java.security.MessageDigest;
6import java.security.NoSuchAlgorithmException;
7import java.security.SecureRandom;
8
9import eu.siacs.conversations.entities.Account;
10import android.util.Base64;
11
12public class CryptoHelper {
13 public static final String FILETRANSFER = "?FILETRANSFERv1:";
14 final protected static char[] hexArray = "0123456789abcdef".toCharArray();
15 final protected static char[] vowels = "aeiou".toCharArray();
16 final protected static char[] consonants = "bcdfghjklmnpqrstvwxyz"
17 .toCharArray();
18
19 public static String bytesToHex(byte[] bytes) {
20 char[] hexChars = new char[bytes.length * 2];
21 for (int j = 0; j < bytes.length; j++) {
22 int v = bytes[j] & 0xFF;
23 hexChars[j * 2] = hexArray[v >>> 4];
24 hexChars[j * 2 + 1] = hexArray[v & 0x0F];
25 }
26 return new String(hexChars);
27 }
28
29 public static byte[] hexToBytes(String hexString) {
30 int len = hexString.length();
31 byte[] array = new byte[len / 2];
32 for (int i = 0; i < len; i += 2) {
33 array[i / 2] = (byte) ((Character.digit(hexString.charAt(i), 16) << 4) + Character
34 .digit(hexString.charAt(i + 1), 16));
35 }
36 return array;
37 }
38
39 public static String saslPlain(String username, String password) {
40 String sasl = '\u0000' + username + '\u0000' + password;
41 return Base64.encodeToString(sasl.getBytes(Charset.defaultCharset()),
42 Base64.NO_WRAP);
43 }
44
45 private static byte[] concatenateByteArrays(byte[] a, byte[] b) {
46 byte[] result = new byte[a.length + b.length];
47 System.arraycopy(a, 0, result, 0, a.length);
48 System.arraycopy(b, 0, result, a.length, b.length);
49 return result;
50 }
51
52 public static String saslDigestMd5(Account account, String challenge,
53 SecureRandom random) {
54 try {
55 String[] challengeParts = new String(Base64.decode(challenge,
56 Base64.DEFAULT)).split(",");
57 String nonce = "";
58 for (int i = 0; i < challengeParts.length; ++i) {
59 String[] parts = challengeParts[i].split("=");
60 if (parts[0].equals("nonce")) {
61 nonce = parts[1].replace("\"", "");
62 } else if (parts[0].equals("rspauth")) {
63 return null;
64 }
65 }
66 String digestUri = "xmpp/" + account.getServer();
67 String nonceCount = "00000001";
68 String x = account.getUsername() + ":" + account.getServer() + ":"
69 + account.getPassword();
70 MessageDigest md = MessageDigest.getInstance("MD5");
71 byte[] y = md.digest(x.getBytes(Charset.defaultCharset()));
72 String cNonce = new BigInteger(100, random).toString(32);
73 byte[] a1 = concatenateByteArrays(y,
74 (":" + nonce + ":" + cNonce).getBytes(Charset
75 .defaultCharset()));
76 String a2 = "AUTHENTICATE:" + digestUri;
77 String ha1 = bytesToHex(md.digest(a1));
78 String ha2 = bytesToHex(md.digest(a2.getBytes(Charset
79 .defaultCharset())));
80 String kd = ha1 + ":" + nonce + ":" + nonceCount + ":" + cNonce
81 + ":auth:" + ha2;
82 String response = bytesToHex(md.digest(kd.getBytes(Charset
83 .defaultCharset())));
84 String saslString = "username=\"" + account.getUsername()
85 + "\",realm=\"" + account.getServer() + "\",nonce=\""
86 + nonce + "\",cnonce=\"" + cNonce + "\",nc=" + nonceCount
87 + ",qop=auth,digest-uri=\"" + digestUri + "\",response="
88 + response + ",charset=utf-8";
89 return Base64.encodeToString(
90 saslString.getBytes(Charset.defaultCharset()),
91 Base64.NO_WRAP);
92 } catch (NoSuchAlgorithmException e) {
93 return null;
94 }
95 }
96
97 public static String randomMucName(SecureRandom random) {
98 return randomWord(3, random) + "." + randomWord(7, random);
99 }
100
101 protected static String randomWord(int lenght, SecureRandom random) {
102 StringBuilder builder = new StringBuilder(lenght);
103 for (int i = 0; i < lenght; ++i) {
104 if (i % 2 == 0) {
105 builder.append(consonants[random.nextInt(consonants.length)]);
106 } else {
107 builder.append(vowels[random.nextInt(vowels.length)]);
108 }
109 }
110 return builder.toString();
111 }
112}