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ZRTP for Java library, Jitsi fork without embedded ciphers
/*
* Copyright (C) 2006-2008 Werner Dittmann
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see
*/
/**
*
* Copyright (c) 2002 Bryce "Zooko" Wilcox-O'Hearn Permission is hereby
* granted, free of charge, to any person obtaining a copy of this software to
* deal in this software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of this software, and to permit persons to whom this software
* is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of this software.
*
* THIS SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THIS SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THIS SOFTWARE.
*
* Converted to Java by: Werner Dittmann
*/
package gnu.java.zrtp.utils;
/**
* @author Werner Dittmann <[email protected]>
*
*/
public class Base32 {
// 1 2 3
// 01234567890123456789012345678901
private static final char[] chars = "ybndrfg8ejkmcpqxot1uwisza345h769".toCharArray();
/*
* revchars: index into this table with the ASCII value of the char.
* The result is the value of that quintet.
*/
private static int[] revchars = {
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 18, 255, 25, 26, 27, 30, 29,
7, 31, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 24, 1, 12, 3, 8, 5, 6,
28, 21, 9, 10, 255, 11, 2, 16,
13, 14, 4, 22, 17, 19, 255, 20,
15, 0, 23, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255
};
public static int divceil(int a, int b) {
int c;
if (a > 0) {
if (b > 0) c = a + b - 1;
else c = a;
} else {
if (b > 0) c = a;
else c = a + b + 1;
}
return c/b;
}
/**
* Encode binary data into a Base32 string.
*
* The method returns a string that contains the base32 encoded
* data.
*
* @param os The byte array containing the binary data. The length
* must be at least (lengthInBits + 7) / 8 .
* @param lengthInBits Defines how may bits of the binary data shall be
* encoded into a base32 string.
* @return
* The string containing the base32 encoded data.
*/
public static String binary2ascii(byte[] os, int lengthInBits) {
/* if lengthInBits is not a multiple of 8 then this is allocating
* space for 0, 1, or 2 extra quintets that will be truncated at the
* end of this function if they are not needed
*/
int len = (lengthInBits + 7) / 8;
char[] result = new char[divceil(len*8, 5)];
for (int i = 0; i < result.length; i++) {
result[i] = ' ';
}
/* index into the result buffer, initially pointing to the
* "one-past-the-end" quintet
*/
int resp = result.length;
int x = 0; // to hold up to 32 bits worth of the input
// Now this is a real live Duff's device, modifyed for Java usage. You gotta love it.
int switcher = len % 5;
do {
switch (switcher) {
case 0:
x = os[--len] & 0xff;
result[--resp] = chars[x % 32]; /* The least sig 5 bits go into the final quintet. */
x /= 32; /* ... now we have 3 bits worth in x... */
case 4:
x |= (os[--len]&0xff) << 3; /* ... now we have 11 bits worth in x... */
result[--resp] = chars[x % 32];
x /= 32; /* ... now we have 6 bits worth in x... */
result[--resp] = chars[x % 32];
x /= 32; /* ... now we have 1 bits worth in x... */
case 3:
x |= (os[--len] & 0xff) << 1; /* The 8 bits from the 2-indexed octet.
So now we have 9 bits worth in x... */
result[--resp] = chars[x % 32];
x /= 32; /* ... now we have 4 bits worth in x... */
case 2:
x |= (os[--len] & 0xff) << 4; /* The 8 bits from the 1-indexed octet.
So now we have 12 bits worth in x... */
result[--resp] = chars[x%32];
x /= 32; /* ... now we have 7 bits worth in x... */
result[--resp] = chars[x%32];
x /= 32; /* ... now we have 2 bits worth in x... */
case 1:
x |= (os[--len] & 0xff) << 2; /* The 8 bits from the 0-indexed octet.
So now we have 10 bits worth in x... */
result[--resp] = chars[x%32];
x /= 32; /* ... now we have 5 bits worth in x... */
result[--resp] = chars[x];
} /* switch (switcher) */
switcher = 0;
} while (len > 0);
/* truncate any unused trailing zero quintets */
return new String(result, 0, divceil(lengthInBits, 5));
}
/**
* Decode a Base32 string into binary data.
*
* The method returns a byte array that contains the binary data
* that was decoded from the base32 string.
*
* @param cs The String containing the base32 data. The length
* must be at least (lengthInBits + 5 - 1) / 5 characters .
* @param lengthInBits Defines how may bits shall be decoded from the
* String.
* @return
* The byte array containg the decoded data.
*/
@SuppressWarnings("unused")
public static byte[] ascii2binary(String cs, int lengthInBits ) {
int x = 0; // to hold up to 32 bits worth of the input
int size = divceil(lengthInBits, 5); // minimum length of input String
/* if lengthinbits is not a multiple of 5 then this is
* allocating space for 0 or 1 extra octets that will be
* truncated at the end of this function if they are
* not needed
*/
int len = divceil(size*5, 8);
byte[] binaryResult = new byte[len];
/* offset into the result buffer, initially pointing to
* the "one-past-the-end" octet
*/
int resp = binaryResult.length;
/* index into the input buffer, initially pointing to the
* "one-past-the-end" character
*/
int csp = size;
/* Now this is a real live Duff's device, modifyed for Java usage. You gotta love it. */
int switcher = csp % 8;
do {
switch (switcher) {
case 0:
x = revchars[cs.charAt(--csp)& 0xff]; /* 5 bits... */
case 7:
x |= revchars[cs.charAt(--csp)& 0xff] << 5; /* 10 bits... */
binaryResult[--resp] = (byte)(x % 256);
x /= 256; /* 2 bits... */
case 6:
x |= revchars[cs.charAt(--csp)& 0xff] << 2; /* 7 bits... */
case 5:
x |= revchars[cs.charAt(--csp)& 0xff] << 7; /* 12 bits... */
binaryResult[--resp] = (byte)(x % 256);
x /= 256; /* 4 bits... */
case 4:
x |= revchars[cs.charAt(--csp)& 0xff] << 4; /* 9 bits... */
binaryResult[--resp] = (byte)(x % 256);
x /= 256; /* 1 bit... */
case 3:
x |= revchars[cs.charAt(--csp)& 0xff] << 1; /* 6 bits... */
case 2:
x |= revchars[cs.charAt(--csp)& 0xff] << 6; /* 11 bits... */
binaryResult[--resp] = (byte)(x % 256);
x /= 256; /* 3 bits... */
case 1:
x |= revchars[cs.charAt(--csp)& 0xff] << 3; /* 8 bits... */
binaryResult[--resp] = (byte)(x % 256);
} /* switch ((csp - cs.buf) % 8) */
switcher = 0;
} while (csp > 0);
/* truncate any unused trailing zero octets */
int resultLength = divceil(lengthInBits, 8);
if (resultLength < len) {
byte[] shorterResult = new byte[resultLength];
System.arraycopy(binaryResult, 0, shorterResult, 0, shorterResult.length);
return shorterResult;
}
return binaryResult;
}
// public static void main(String[] args)
// {
// byte[] ones = {1, 1, 1, 1, 1};
// byte[] onesMore = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
// byte[] eightOne = {(byte)0x81, (byte)0x81, (byte)0x81, (byte)0x81,
// (byte)0x81, (byte)0x81, (byte)0x81, (byte)0x81};
//
// String encoded = binary2ascii(ones, 40);
// System.err.println("Endcoded zeroOne, 40bits (expected: 'yryonyeb'): " + encoded);
// encoded = binary2ascii(ones, 15);
// System.err.println("Endcoded zeroOne, 15bits (expected: 'yry'): " + encoded);
// encoded = binary2ascii(onesMore, 80);
// System.err.println("Endcoded zeroOne, 80bits (expected: 'yryonyebyryonyeb'): " + encoded);
// byte[] decoded = ascii2binary(encoded, 80);
// ZrtpUtils.hexdump("Decoded 80 bits zeroOne", decoded, decoded.length);
// decoded = ascii2binary(encoded, 8);
// ZrtpUtils.hexdump("Decoded 8 bits zeroOne", decoded, decoded.length);
//
// encoded = binary2ascii(eightOne, 15);
// System.err.println("Endcoded eightOne, 15bits (expected: 'ogy'): " + encoded);
// encoded = binary2ascii(eightOne, 16);
// System.err.println("Endcoded eightOne, 16bits (expected: 'ogyo'): " + encoded);
// encoded = binary2ascii(eightOne, 20);
// System.err.println("Endcoded eightOne, 20bits (expected: 'ogya'): " + encoded);
// encoded = binary2ascii(eightOne, 64);
// System.err.println("Endcoded eightOne, 64bits (expected: 'ogyadycbogyan'): " + encoded);
//
// decoded = ascii2binary(encoded, 7);
// ZrtpUtils.hexdump("Decoded 7 bits eightOne", decoded, decoded.length);
// decoded = ascii2binary(encoded, 8);
// ZrtpUtils.hexdump("Decoded 8 bits eightOne", decoded, decoded.length);
// decoded = ascii2binary(encoded, 15);
// ZrtpUtils.hexdump("Decoded 15 bits eightOne", decoded, decoded.length);
// decoded = ascii2binary(encoded, 16);
// ZrtpUtils.hexdump("Decoded 16 bits eightOne", decoded, decoded.length);
// decoded = ascii2binary(encoded, 64);
// ZrtpUtils.hexdump("Decoded 64 bits eightOne", decoded, decoded.length);
// }
}