Mega Code Archive
Util for digesting and encoding bytesstrings
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//Copyright 2007-2008 David Yu dyuproject@gmail.com
//------------------------------------------------------------------------
//Licensed under the Apache License, Version 2.0 (the "License");
//you may not use this file except in compliance with the License.
//You may obtain a copy of the License at
//http://www.apache.org/licenses/LICENSE-2.0
//Unless required by applicable law or agreed to in writing, software
//distributed under the License is distributed on an "AS IS" BASIS,
//WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//See the License for the specific language governing permissions and
//limitations under the License.
//package com.dyuproject.util;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
/**
* Util for digesting and encoding bytes/strings.
*
* @author David Yu
* @created Sep 7, 2008
*/
public final class DigestUtil
{
/**
* "MD5"
*/
public static final String MD5 = "MD5";
/**
* "SHA-1"
*/
public static final String SHA1 = "SHA-1";
/**
* "SHA-256"
*/
public static final String SHA256 = "SHA-256";
/**
* The hex chars as bytes.
*/
public static final byte[] HEXADECIMAL =
{
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
0x61, 0x62, 0x63, 0x64, 0x65, 0x66
};
/**
* Returns the bytes {@code data} in hex form.
*/
public static byte[] getHexBytes(byte[] data)
{
byte[] out = new byte[data.length*2];
for (int i=0,y=0; i<data.length; i++)
{
int l = (data[i] & 0xf0) >> 4;
int r = data[i] & 0x0f;
out[y++] = HEXADECIMAL[l];
out[y++] = HEXADECIMAL[r];
}
return out;
}
/**
* Returns the bytes {@code data} in hex form as characters.
*/
public static char[] getHexChars(byte[] data)
{
char[] out = new char[data.length*2];
for (int i=0,y=0; i<data.length; i++)
{
int l = (data[i] & 0xf0) >> 4;
int r = data[i] & 0x0f;
out[y++] = (char)HEXADECIMAL[l];
out[y++] = (char)HEXADECIMAL[r];
}
return out;
}
static String getHexString(byte[] data)
{
return new String(getHexBytes(data));
}
/**
* Returns the bytes {@code data} in hex form as string.
*/
public static String getHexString(byte[] data, String charset)
throws UnsupportedEncodingException
{
return new String(getHexBytes(data), charset);
}
/**
* Digests the {@code data} with the specified {@code type} and {@code charset}.
*/
public static String getDigestedValue(String type, String data, String charset)
throws UnsupportedEncodingException
{
return getDigestedValue(type, data.getBytes(charset), charset);
}
/**
* Digests the {@code data} with the specified {@code type}.
*/
public static String getDigestedValue(String type, String data)
{
return getDigestedValue(type, data.getBytes());
}
static String getDigestedValue(String type, byte[] data, String charset)
{
try
{
MessageDigest digest = MessageDigest.getInstance(type);
return getHexString(digest.digest(data), charset);
}
catch(Exception e)
{
e.printStackTrace();
return null;
}
}
static String getDigestedValue(String type, byte[] data)
{
try
{
MessageDigest digest = MessageDigest.getInstance(type);
return getHexString(digest.digest(data));
}
catch(Exception e)
{
e.printStackTrace();
return null;
}
}
/**
* Digests the {@code data} with the specified {@code type} and returns the
* raw unencoded bytes.
*/
public static byte[] getPlainDigestedValue(String type, byte[] data)
{
try
{
MessageDigest digest = MessageDigest.getInstance(type);
return digest.digest(data);
}
catch(Exception e)
{
e.printStackTrace();
return null;
}
}
/**
* Digests the {@code data} with MD5 and returns the raw unencoded bytes.
*/
public static String digestMD5(String data)
{
return getDigestedValue(MD5, data.getBytes());
}
/**
* Digests the {@code data} with MD5 and the specified {@code charset} and
* returns the raw unencoded bytes.
*/
public static String digestMD5(String data, String charset)
{
try
{
return getDigestedValue(MD5, data, charset);
}
catch (Exception e)
{
e.printStackTrace();
return null;
}
}
/**
* Digests the {@code data} with SHA-1 and returns the raw unencoded bytes.
*/
public static String digestSHA1(String data)
{
return getDigestedValue(SHA1, data.getBytes());
}
/**
* Digests the {@code data} with SHA-1 and the specified {@code charset} and
* returns the raw unencoded bytes.
*/
public static String digestSHA1(String data, String charset)
{
try
{
return getDigestedValue(SHA1, data, charset);
}
catch (Exception e)
{
e.printStackTrace();
return null;
}
}
/**
* Digests the {@code data} with SHA-256 and returns the raw unencoded bytes.
*/
public static String digestSHA256(String data)
{
return getDigestedValue(SHA256, data.getBytes());
}
/**
* Digests the {@code data} with SHA-256 and the specified {@code charset} and
* returns the raw unencoded bytes.
*/
public static String digestSHA256(String data, String charset)
{
try
{
return getDigestedValue(SHA256, data, charset);
}
catch (Exception e)
{
e.printStackTrace();
return null;
}
}
}
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