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Draagon Utilities used by other Draagon projects
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package com.draagon.util;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import javax.crypto.spec.SecretKeySpec;
public class EncryptionUtil {
private static String ALGORITHM = "DESede";
/** Our default secret key, shhh! Don't tell anybody about it!
* If you want to create a new one (and thus invalidate all existing encrypted
* data), just run method generateKey() and store its value here. Then call
* setPrivatekey() in an initialization block of your code.
*/
private static String privatekey = "9JiPL4ws33auLxqe04Ms9xbWSRO6StA0";
/**
* This array is a lookup table that translates 6-bit positive integer
* index values into their "Base64 Alphabet" equivalents as specified
* in Table 1 of RFC 2045.
*/
private static final char intToBase64[] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
};
/**
* This array is a lookup table that translates unicode characters
* drawn from the "Base64 Alphabet" (as specified in Table 1 of RFC 2045)
* into their 6-bit positive integer equivalents. Characters that
* are not in the Base64 alphabet but fall within the bounds of the
* array are translated to -1.
*/
private static final byte base64ToInt[] = {
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54,
55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4,
5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34,
35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
};
/**
* Translates the specified character, which is assumed to be in the
* "Base 64 Alphabet" into its equivalent 6-bit positive integer.
*
* @throw IllegalArgumentException or ArrayOutOfBoundsException if
* c is not in the Base64 Alphabet.
*/
private static int base64toInt(char c, byte[] alphaToInt) {
int result = alphaToInt[c];
if (result < 0)
throw new IllegalArgumentException("Illegal character " + c);
return result;
}
/** Convert given byte array to base 64. */
private static String byteArrayToBase64(byte[] a) {
int aLen = a.length;
int numFullGroups = aLen/3;
int numBytesInPartialGroup = aLen - 3*numFullGroups;
int resultLen = 4*((aLen + 2)/3);
StringBuffer result = new StringBuffer(resultLen);
char[] intToAlpha = intToBase64;
// Translate all full groups from byte array elements to Base64
int inCursor = 0;
for (int i=0; i> 2]);
result.append(intToAlpha[(byte0 << 4)&0x3f | (byte1 >> 4)]);
result.append(intToAlpha[(byte1 << 2)&0x3f | (byte2 >> 6)]);
result.append(intToAlpha[byte2 & 0x3f]);
}
// Translate partial group if present
if (numBytesInPartialGroup != 0) {
int byte0 = a[inCursor++] & 0xff;
result.append(intToAlpha[byte0 >> 2]);
if (numBytesInPartialGroup == 1) {
result.append(intToAlpha[(byte0 << 4) & 0x3f]);
result.append("==");
} else {
// assert numBytesInPartialGroup == 2;
int byte1 = a[inCursor++] & 0xff;
result.append(intToAlpha[(byte0 << 4)&0x3f | (byte1 >> 4)]);
result.append(intToAlpha[(byte1 << 2)&0x3f]);
result.append('=');
}
}
// assert inCursor == a.length;
// assert result.length() == resultLen;
return result.toString();
}
/** Decode given base 64 string to byte array. */
private static byte[] base64ToByteArray(String s) {
byte[] alphaToInt = base64ToInt;
int sLen = s.length();
int numGroups = sLen/4;
if (4*numGroups != sLen)
throw new IllegalArgumentException(
"String length must be a multiple of four.");
int missingBytesInLastGroup = 0;
int numFullGroups = numGroups;
if (sLen != 0) {
if (s.charAt(sLen-1) == '=') {
missingBytesInLastGroup++;
numFullGroups--;
}
if (s.charAt(sLen-2) == '=')
missingBytesInLastGroup++;
}
byte[] result = new byte[3*numGroups - missingBytesInLastGroup];
// Translate all full groups from base64 to byte array elements
int inCursor = 0, outCursor = 0;
for (int i=0; i> 4));
result[outCursor++] = (byte) ((ch1 << 4) | (ch2 >> 2));
result[outCursor++] = (byte) ((ch2 << 6) | ch3);
}
// Translate partial group, if present
if (missingBytesInLastGroup != 0) {
int ch0 = base64toInt(s.charAt(inCursor++), alphaToInt);
int ch1 = base64toInt(s.charAt(inCursor++), alphaToInt);
result[outCursor++] = (byte) ((ch0 << 2) | (ch1 >> 4));
if (missingBytesInLastGroup == 1) {
int ch2 = base64toInt(s.charAt(inCursor++), alphaToInt);
result[outCursor++] = (byte) ((ch1 << 4) | (ch2 >> 2));
}
}
// assert inCursor == s.length()-missingBytesInLastGroup;
// assert outCursor == result.length;
return result;
}
/** Generate key, primarily useful during development to get a key. */
public static String generateKey() throws Exception {
KeyGenerator keygen = KeyGenerator.getInstance(ALGORITHM);
SecretKey key = keygen.generateKey();
SecretKeyFactory desEdeFactory = SecretKeyFactory.getInstance(ALGORITHM);
DESedeKeySpec desEdeSpec = (DESedeKeySpec)
desEdeFactory.getKeySpec(key, javax.crypto.spec.DESedeKeySpec.class);
byte[] rawDesEdeKey = desEdeSpec.getKey();
return byteArrayToBase64(rawDesEdeKey);
}
/** Sets the private key to use for encryption/decryption */
public static void setPrivateKey( String key ) {
privatekey = key;
}
/** Return private key. Note that this way of creating key doesn't work for all ciphers. */
private static SecretKeySpec getPrivateKey() {
return new SecretKeySpec(base64ToByteArray(privatekey), ALGORITHM);
}
/** Encrypt given text. */
public static String encrypt( String plaintext ) {
try {
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, getPrivateKey());
byte[] ciphertext = cipher.doFinal(plaintext.getBytes());
return byteArrayToBase64(ciphertext);
}
catch( Exception e ) {
throw new RuntimeException( "Could not encrypt string [" + plaintext + "]: " + e.getMessage(), e );
}
}
/** Decrypt given text. */
public static String decrypt( String ciphertext ) {
try {
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, getPrivateKey());
byte[] plaintext = cipher.doFinal(base64ToByteArray(ciphertext));
return new String( plaintext );
}
catch( Exception e ) {
throw new RuntimeException( "Could not decrypt string [" + ciphertext + "]: " + e.getMessage(), e );
}
}
public static void main(String argv[]) throws Exception {
String key = EncryptionUtil.generateKey();
System.out.println("New key (" + key.length() + " chars): " + key);
String plaintext, encrypted, decrypted;
plaintext = "insight";
encrypted = EncryptionUtil.encrypt(plaintext);
System.out.println("Encrypted to: " + encrypted);
decrypted = EncryptionUtil.decrypt(encrypted);
System.out.println("Decrypted to: " + decrypted);
if( decrypted.equals( plaintext ) ) {
System.out.println("Success, they MATCH!!!");
} else {
System.out.println("Failure, they do NOT MATCH!!!");
}
}
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