netbout-spi-1.5.6.src.main.java.com.netbout.spi.text.SecureString Maven / Gradle / Ivy
/**
* Copyright (c) 2009-2012, Netbout.com
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met: 1) Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer. 2) Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution. 3) Neither the name of the NetBout.com nor
* the names of its contributors may be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
* NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.netbout.spi.text;
import com.rexsl.core.Manifests;
import org.apache.commons.lang.CharEncoding;
/**
* String, which encrypts itself.
*
* Objects of this class are immutable and thread-safe.
*
* @author Yegor Bugayenko ([email protected])
* @version $Id: SecureString.java 3470 2012-10-16 18:46:28Z [email protected] $
* @see One Time Pad
* @see Base64
* @checkstyle MagicNumber (500 lines)
*/
public final class SecureString {
/**
* Open content (without encryption).
*/
private final transient String raw;
/**
* Public ctor.
* @param text The text (without encryption)
*/
public SecureString(final Object text) {
this.raw = text.toString();
}
/**
* {@inheritDoc}
*/
@Override
public String toString() {
return SecureString.pack(SecureString.xor(this.raw.getBytes()));
}
/**
* Create it from encrypted input.
* @param hash The hash to use
* @return The string
* @throws StringDecryptionException When can't decrypt
*/
public static SecureString valueOf(final String hash)
throws StringDecryptionException {
try {
return new SecureString(
new String(
SecureString.xor(SecureString.unpack(hash)),
CharEncoding.UTF_8
)
);
} catch (java.io.UnsupportedEncodingException ex) {
throw new IllegalStateException(ex);
}
}
/**
* Get its original text, without encryption.
* @return The text
*/
public String text() {
return this.raw;
}
/**
* XOR array of bytes.
* @param input The input to XOR
* @return Encrypted output
*/
private static byte[] xor(final byte[] input) {
final byte[] output = new byte[input.length];
final byte[] secret = Manifests.read("Netbout-SecurityKey").getBytes();
if (secret.length == 0) {
throw new IllegalStateException("empty security key");
}
int spos = 0;
for (int pos = 0; pos < input.length; ++pos) {
output[pos] = (byte) (input[pos] ^ secret[spos]);
++spos;
if (spos >= secret.length) {
spos = 0;
}
}
return output;
}
/**
* Pack array of bytes into string.
* @param input The array of bytes
* @return Packed output
*/
private static String pack(final byte[] input) {
final StringBuilder text = new StringBuilder();
int buffer = 0;
int bits = 0;
for (int pos = 0; pos < input.length; ++pos) {
buffer = (buffer << 8) | (0xFF & input[pos]);
bits += 8;
while (bits >= 5) {
text.append(
SecureString.toChar(
(byte) ((buffer >> (bits - 5)) & 0x1F)
)
);
bits -= 5;
}
}
if (bits > 0) {
text.append(
SecureString.toChar((byte) ((buffer << (5 - bits)) & 0x1F))
);
}
return text.toString();
}
/**
* Unpack sting into array of bytes.
* @param input The packed string
* @return Unpacked output
* @throws StringDecryptionException When can't unpack
*/
private static byte[] unpack(final String input)
throws StringDecryptionException {
final int length = input.length();
final byte[] output = new byte[length * 5 / 8];
long buffer = 0;
int bits = 0;
int opos = 0;
for (int pos = 0; pos < length; pos += 1) {
buffer = (buffer << 5) + SecureString.toBits(input.charAt(pos));
bits += 5;
while (bits >= 8) {
output[opos] = (byte) (buffer >> (bits - 8));
opos += 1;
bits -= 8;
}
}
return output;
}
/**
* Convert 5 bits to one char.
* @param bits The bits
* @return The char
*/
private static char toChar(final byte bits) {
char output;
if (bits >= 0 && bits <= 6) {
output = (char) ('0' + bits);
} else if (bits >= 7 && bits <= 32) {
output = (char) ('A' + bits - 7);
} else {
throw new IllegalArgumentException(
String.format("Illegal bits value: '%d'", bits)
);
}
return output;
}
/**
* Convert char to 5 bits.
* @param symbol The character
* @return The bits
* @throws StringDecryptionException When can't decrypt
*/
private static byte toBits(final char symbol)
throws StringDecryptionException {
byte output;
if (symbol >= 'A' && symbol <= 'Z') {
output = (byte) (symbol - 'A' + 7);
} else if (symbol >= '0' && symbol <= '6') {
output = (byte) (symbol - '0');
} else {
throw new StringDecryptionException(
String.format("Illegal character in Base32: '%s'", symbol)
);
}
return output;
}
}