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package eu.siacs.conversations.utils;
import java.math.BigInteger;
import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import eu.siacs.conversations.entities.Account;
import android.util.Base64;
public class CryptoHelper {
public static final String FILETRANSFER = "?FILETRANSFERv1:";
final protected static char[] hexArray = "0123456789abcdef".toCharArray();
final protected static char[] vowels = "aeiou".toCharArray();
final protected static char[] consonants = "bcdfghjklmnpqrstvwxyz"
.toCharArray();
public static String bytesToHex(byte[] bytes) {
char[] hexChars = new char[bytes.length * 2];
for (int j = 0; j < bytes.length; j++) {
int v = bytes[j] & 0xFF;
hexChars[j * 2] = hexArray[v >>> 4];
hexChars[j * 2 + 1] = hexArray[v & 0x0F];
}
return new String(hexChars);
}
public static byte[] hexToBytes(String hexString) {
int len = hexString.length();
byte[] array = new byte[len / 2];
for (int i = 0; i < len; i += 2) {
array[i / 2] = (byte) ((Character.digit(hexString.charAt(i), 16) << 4) + Character
.digit(hexString.charAt(i + 1), 16));
}
return array;
}
public static String saslPlain(String username, String password) {
String sasl = '\u0000' + username + '\u0000' + password;
return Base64.encodeToString(sasl.getBytes(Charset.defaultCharset()),
Base64.NO_WRAP);
}
private static byte[] concatenateByteArrays(byte[] a, byte[] b) {
byte[] result = new byte[a.length + b.length];
System.arraycopy(a, 0, result, 0, a.length);
System.arraycopy(b, 0, result, a.length, b.length);
return result;
}
public static String saslDigestMd5(Account account, String challenge,
SecureRandom random) {
try {
String[] challengeParts = new String(Base64.decode(challenge,
Base64.DEFAULT)).split(",");
String nonce = "";
for (int i = 0; i < challengeParts.length; ++i) {
String[] parts = challengeParts[i].split("=");
if (parts[0].equals("nonce")) {
nonce = parts[1].replace("\"", "");
} else if (parts[0].equals("rspauth")) {
return null;
}
}
String digestUri = "xmpp/" + account.getServer();
String nonceCount = "00000001";
String x = account.getUsername() + ":" + account.getServer() + ":"
+ account.getPassword();
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] y = md.digest(x.getBytes(Charset.defaultCharset()));
String cNonce = new BigInteger(100, random).toString(32);
byte[] a1 = concatenateByteArrays(y,
(":" + nonce + ":" + cNonce).getBytes(Charset
.defaultCharset()));
String a2 = "AUTHENTICATE:" + digestUri;
String ha1 = bytesToHex(md.digest(a1));
String ha2 = bytesToHex(md.digest(a2.getBytes(Charset
.defaultCharset())));
String kd = ha1 + ":" + nonce + ":" + nonceCount + ":" + cNonce
+ ":auth:" + ha2;
String response = bytesToHex(md.digest(kd.getBytes(Charset
.defaultCharset())));
String saslString = "username=\"" + account.getUsername()
+ "\",realm=\"" + account.getServer() + "\",nonce=\""
+ nonce + "\",cnonce=\"" + cNonce + "\",nc=" + nonceCount
+ ",qop=auth,digest-uri=\"" + digestUri + "\",response="
+ response + ",charset=utf-8";
return Base64.encodeToString(
saslString.getBytes(Charset.defaultCharset()),
Base64.NO_WRAP);
} catch (NoSuchAlgorithmException e) {
return null;
}
}
public static String randomMucName(SecureRandom random) {
return randomWord(3, random) + "." + randomWord(7, random);
}
protected static String randomWord(int lenght, SecureRandom random) {
StringBuilder builder = new StringBuilder(lenght);
for (int i = 0; i < lenght; ++i) {
if (i % 2 == 0) {
builder.append(consonants[random.nextInt(consonants.length)]);
} else {
builder.append(vowels[random.nextInt(vowels.length)]);
}
}
return builder.toString();
}
}
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