1 files changed, 112 insertions, 0 deletions
diff --git a/conversations/src/main/java/eu/siacs/conversations/utils/CryptoHelper.java b/conversations/src/main/java/eu/siacs/conversations/utils/CryptoHelper.java
new file mode 100644
index 00000000..47595c6e
--- /dev/null
+++ b/conversations/src/main/java/eu/siacs/conversations/utils/CryptoHelper.java
@@ -0,0 +1,112 @@
+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();
+	}
+}