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Diffstat (limited to 'src/main/java/eu/siacs/conversations/utils/CryptoHelper.java')
-rw-r--r--src/main/java/eu/siacs/conversations/utils/CryptoHelper.java129
1 files changed, 129 insertions, 0 deletions
diff --git a/src/main/java/eu/siacs/conversations/utils/CryptoHelper.java b/src/main/java/eu/siacs/conversations/utils/CryptoHelper.java
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index 00000000..2dec203d
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+++ b/src/main/java/eu/siacs/conversations/utils/CryptoHelper.java
@@ -0,0 +1,129 @@
+package eu.siacs.conversations.utils;
+
+import java.security.SecureRandom;
+import java.text.Normalizer;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.LinkedHashSet;
+import java.util.List;
+
+import eu.siacs.conversations.Config;
+
+public final class CryptoHelper {
+ public static final String FILETRANSFER = "?FILETRANSFERv1:";
+ private final static char[] hexArray = "0123456789abcdef".toCharArray();
+ private final static char[] vowels = "aeiou".toCharArray();
+ private final static char[] consonants = "bcdfghjklmnpqrstvwxyz".toCharArray();
+ final public static byte[] ONE = new byte[] { 0, 0, 0, 1 };
+
+ 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 hexToString(final String hexString) {
+ return new String(hexToBytes(hexString));
+ }
+
+ public 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 randomMucName(SecureRandom random) {
+ return randomWord(3, random) + "." + randomWord(7, random);
+ }
+
+ private 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();
+ }
+
+ /**
+ * Escapes usernames or passwords for SASL.
+ */
+ public static String saslEscape(final String s) {
+ final StringBuilder sb = new StringBuilder((int) (s.length() * 1.1));
+ for (int i = 0; i < s.length(); i++) {
+ char c = s.charAt(i);
+ switch (c) {
+ case ',':
+ sb.append("=2C");
+ break;
+ case '=':
+ sb.append("=3D");
+ break;
+ default:
+ sb.append(c);
+ break;
+ }
+ }
+ return sb.toString();
+ }
+
+ public static String saslPrep(final String s) {
+ return Normalizer.normalize(s, Normalizer.Form.NFKC);
+ }
+
+ public static String prettifyFingerprint(String fingerprint) {
+ if (fingerprint==null) {
+ return "";
+ } else if (fingerprint.length() < 40) {
+ return fingerprint;
+ }
+ StringBuilder builder = new StringBuilder(fingerprint);
+ builder.insert(8, " ");
+ builder.insert(17, " ");
+ builder.insert(26, " ");
+ builder.insert(35, " ");
+ return builder.toString();
+ }
+
+ public static String[] getOrderedCipherSuites(final String[] platformSupportedCipherSuites) {
+ final Collection<String> cipherSuites = new LinkedHashSet<>(Arrays.asList(Config.ENABLED_CIPHERS));
+ final List<String> platformCiphers = Arrays.asList(platformSupportedCipherSuites);
+ cipherSuites.retainAll(platformCiphers);
+ cipherSuites.addAll(platformCiphers);
+ filterWeakCipherSuites(cipherSuites);
+ return cipherSuites.toArray(new String[cipherSuites.size()]);
+ }
+
+ private static void filterWeakCipherSuites(final Collection<String> cipherSuites) {
+ final Iterator<String> it = cipherSuites.iterator();
+ while (it.hasNext()) {
+ String cipherName = it.next();
+ // remove all ciphers with no or very weak encryption or no authentication
+ for (String weakCipherPattern : Config.WEAK_CIPHER_PATTERNS) {
+ if (cipherName.contains(weakCipherPattern)) {
+ it.remove();
+ break;
+ }
+ }
+ }
+ }
+}