Java crypto library:
Example:
Crypto _c = new Crypto();
Crypto.AES aes = _c .new AES();
int keySizeInBits = 128;
int keySizeInBytes = keySizeInBits/8;
// Derive a cryptographic key: PBKDF2
String salt = Utils.byteArrayToHexString(Utils.getRandomBytes(8));
String key = Utils.pbkdf2("Secret Passphrase", salt, 1000, keySizeInBytes);
// generate IV
byte[] ivBytes = aes.generateIV();
aes.setIV(ivBytes);
/*** encrypt */
String ciphertext = aes.encrypt("plaintext", key);
/*** decrypt */
String plaintext = aes.decrypt(ciphertext, key);
Example JCrypto: JCrypto.jar
Library:
package it.polito.ai;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.InvalidAlgorithmParameterException;
import java.security.NoSuchProviderException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.InvalidParameterSpecException;
import java.security.spec.RSAPublicKeySpec;
import java.util.regex.Pattern;
import java.util.Random;
import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.nio.charset.Charset;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
public class Crypto
{
/*
* AES
*/
public class AES
{
private final String ALGORITHM = "AES"; // symmetric algorithm for data encryption
private final String MODE = "CBC";
private final String PADDING = "PKCS5Padding"; // Padding for symmetric algorithm
private final String CIPHER_TRANSFORMATION = ALGORITHM + "/" + MODE + "/" + PADDING;
private Charset PLAIN_TEXT_ENCODING = Charset.forName("UTF-8"); // character encoding
//private final String CRYPTO_PROVIDER = "SunMSCAPI"; // provider for the crypto
private int KEY_SIZE_BITS = 128; /* symmetric key size (128, 192, 256)
* if using 256 you must have the Java Cryptography Extension (JCE)
* Unlimited Strength Jurisdiction Policy Files installed */
private int KEY_SIZE_BYTES = KEY_SIZE_BITS/8;
private Cipher cipher = Cipher.getInstance(CIPHER_TRANSFORMATION);
private byte[] ivBytes = new byte[KEY_SIZE_BYTES];
private SecretKey key;
public AES()
throws NoSuchAlgorithmException, NoSuchPaddingException, NoSuchProviderException,
InvalidParameterSpecException, InvalidKeyException, InvalidAlgorithmParameterException
{
KeyGenerator kgen = KeyGenerator.getInstance(ALGORITHM);
kgen.init(KEY_SIZE_BITS);
key = kgen.generateKey();
cipher.init(Cipher.ENCRYPT_MODE, key);
ivBytes = cipher.getParameters().getParameterSpec(IvParameterSpec.class).getIV();
}
public String getIVAsHex()
{
return Utils.byteArrayToHexString(ivBytes);
}
public String getKeyAsHex()
{
return Utils.byteArrayToHexString(key.getEncoded());
}
public void setStringToKey(String keyText) throws NoSuchAlgorithmException, UnsupportedEncodingException
{
setKey(keyText.getBytes());
}
public void setHexToKey(String hexKey)
{
setKey(Utils.hexStringToByteArray(hexKey));
}
public void setKey(byte[] bArray)
{
byte[] bText = new byte[KEY_SIZE_BYTES];
int end = Math.min(KEY_SIZE_BYTES, bArray.length);
System.arraycopy(bArray, 0, bText, 0, end);
key = new SecretKeySpec(bText, ALGORITHM);
}
public void setStringToIV(String ivText)
{
setIV(ivText.getBytes());
}
public void setHexToIV(String hexIV)
{
setIV(Utils.hexStringToByteArray(hexIV));
}
public void setIV(byte[] bArray)
{
byte[] bText = new byte[KEY_SIZE_BYTES];
int end = Math.min(KEY_SIZE_BYTES, bArray.length);
System.arraycopy(bArray, 0, bText, 0, end);
ivBytes = bText;
}
public byte[] generateIV()
{
byte[] iv = Utils.getRandomBytes(KEY_SIZE_BYTES);
return iv;
}
public String encrypt(String plaintext, String passphrase)
throws NoSuchAlgorithmException, UnsupportedEncodingException, InvalidKeyException,
InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException
{
if (plaintext.length() == 0) return null;
setStringToKey(passphrase);
cipher.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(ivBytes));
byte[] encrypted = cipher.doFinal(plaintext.getBytes(PLAIN_TEXT_ENCODING));
return Utils.byteArrayToBase64String(encrypted);
}
public String decrypt(String ciphertext, String passphrase)
throws NoSuchAlgorithmException, UnsupportedEncodingException, InvalidKeyException,
InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException
{
if (ciphertext.length() == 0) return null;
setStringToKey(passphrase);
byte[] dec = Utils.base64StringToByteArray(ciphertext);
cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(ivBytes));
byte[] decrypted = cipher.doFinal(dec);
return new String(decrypted, PLAIN_TEXT_ENCODING);
}
}
/*
* PBKDF2: deriveKey
*/
private static class PBKDF2
{
private static byte[] deriveKey(byte[] password, byte[] salt, int iterationCount, int dkLen)
throws NoSuchAlgorithmException, InvalidKeyException
{
SecretKeySpec keyspec = new SecretKeySpec(password, "HmacSHA256");
Mac prf = Mac.getInstance("HmacSHA256");
prf.init( keyspec );
// Note: hLen, dkLen, l, r, T, F, etc. are horrible names for
// variables and functions in this day and age, but they
// reflect the terse symbols used in RFC 2898 to describe
// the PBKDF2 algorithm, which improves validation of the
// code vs. the RFC.
//
// dklen is expressed in bytes. (16 for a 128-bit key)
int hLen = prf.getMacLength(); // 20 for SHA1
int l = Math.max(dkLen, hLen); // 1 for 128bit (16-byte) keys
int r = dkLen - (l-1)*hLen; // 16 for 128bit (16-byte) keys
byte T[] = new byte[l * hLen];
int ti_offset = 0;
for (int i = 1; i <= l; i++) {
F(T, ti_offset, prf, salt, iterationCount, i);
ti_offset += hLen;
}
if (r < hLen) {
// Incomplete last block
byte DK[] = new byte[dkLen];
System.arraycopy(T, 0, DK, 0, dkLen);
return DK;
}
return T;
}
private static void F(byte[] dest, int offset, Mac prf, byte[] S, int c, int blockIndex)
{
final int hLen = prf.getMacLength();
byte U_r[] = new byte[ hLen ];
// U0 = S || INT (i);
byte U_i[] = new byte[S.length + 4];
System.arraycopy(S, 0, U_i, 0, S.length);
INT(U_i, S.length, blockIndex);
for(int i = 0; i < c; i++) {
U_i = prf.doFinal(U_i);
xor( U_r, U_i );
}
System.arraycopy(U_r, 0, dest, offset, hLen);
}
private static void xor(byte[] dest, byte[] src)
{
for(int i = 0; i < dest.length; i++) {
dest[i] ^= src[i];
}
}
private static void INT(byte[] dest, int offset, int i)
{
dest[offset + 0] = (byte) (i / (256 * 256 * 256));
dest[offset + 1] = (byte) (i / (256 * 256));
dest[offset + 2] = (byte) (i / (256));
dest[offset + 3] = (byte) (i);
}
// Costructor
private PBKDF2 () {}
}
/*
* HASH
*/
public class HASH
{
public String MD2(String message) throws NoSuchAlgorithmException
{
MessageDigest md2 = MessageDigest.getInstance("MD2");
byte[] array = md2.digest(message.getBytes());
return arrayToString(array);
}
public String MD5(String message) throws NoSuchAlgorithmException
{
MessageDigest md5 = MessageDigest.getInstance("MD5");
byte[] array = md5.digest(message.getBytes());
return arrayToString(array);
}
public String SHA1(String message) throws NoSuchAlgorithmException
{
MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
byte[] array = sha1.digest(message.getBytes());
return arrayToString(array);
}
public String SHA256(String message) throws NoSuchAlgorithmException
{
MessageDigest sha256 = MessageDigest.getInstance("SHA-256");
byte[] array = sha256.digest(message.getBytes());
return arrayToString(array);
}
public String SHA384(String message) throws NoSuchAlgorithmException
{
MessageDigest sha384 = MessageDigest.getInstance("SHA-384");
byte[] array = sha384.digest(message.getBytes());
return arrayToString(array);
}
public String SHA512(String message) throws NoSuchAlgorithmException
{
MessageDigest sha512 = MessageDigest.getInstance("SHA-512");
byte[] array = sha512.digest(message.getBytes());
return arrayToString(array);
}
private String arrayToString(byte[] array)
{
StringBuffer sb = new StringBuffer();
for (int i = 0; i < array.length; ++i) {
sb.append(Integer.toHexString((array[i] & 0xFF) | 0x100).substring(1,3));
}
return sb.toString();
}
}
/*
* RSA
*/
public class RSA
{
private Charset PLAIN_TEXT_ENCODING = Charset.forName("UTF-8");
private int KEY_SIZE_BITS = 1024;
private Key publicKey;
private Key privateKey;
private BigInteger modulus;
private BigInteger exponent;
Cipher cipher;
KeyFactory fact;
public RSA()
throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException,
UnsupportedEncodingException, InvalidKeyException
{
cipher = Cipher.getInstance("RSA");
fact = KeyFactory.getInstance("RSA");
setNewKey(KEY_SIZE_BITS);
}
public boolean setNewKey(int KeySize)
throws NoSuchAlgorithmException, InvalidKeySpecException
{
if (KeySize <= 0) return false;
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(KeySize);
KeyPair kp = kpg.genKeyPair();
publicKey = kp.getPublic();
privateKey = kp.getPrivate();
RSAPublicKeySpec pub = (RSAPublicKeySpec) fact.getKeySpec(publicKey, RSAPublicKeySpec.class);
modulus = pub.getModulus();
exponent = pub.getPublicExponent();
return true;
}
public BigInteger getModulus()
{
return modulus;
}
public BigInteger getExponent()
{
return exponent;
}
public Key getPublicKey()
{
return publicKey;
}
public Key getPrivateKey()
{
return privateKey;
}
public String encrypt(String plaintext)
throws IllegalBlockSizeException, BadPaddingException, InvalidKeyException
{
if (plaintext.length() == 0) return null;
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] encrypted = cipher.doFinal(plaintext.getBytes());
return Utils.byteArrayToBase64String(encrypted);
}
public String decrypt(String ciphertext)
throws IllegalBlockSizeException, BadPaddingException, InvalidKeyException
{
if (ciphertext.length() == 0) return null;
byte[] dec = Utils.base64StringToByteArray(ciphertext);
cipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] decrypted = cipher.doFinal(dec);
return new String(decrypted, PLAIN_TEXT_ENCODING);
}
}
/*
* Utils
*/
public static class Utils
{
public static String pbkdf2(String password, String salt, int iterationCount, int dkLen)
throws InvalidKeyException, NoSuchAlgorithmException
{
if (dkLen!=16 && dkLen!=24 && dkLen!=32) { dkLen=16; }
if (iterationCount<0) { iterationCount=0; }
byte[] _password = password.getBytes();
byte[] _salt = salt.getBytes();
byte[] key = PBKDF2.deriveKey(_password, _salt, iterationCount, dkLen);
return new String(key);
}
public static byte[] getRandomBytes(int len)
{
if(len<0) { len=8; }
Random ranGen = new SecureRandom();
byte[] aesKey = new byte[len];
ranGen.nextBytes(aesKey);
return aesKey;
}
public static String byteArrayToHexString(byte[] raw)
{
StringBuilder sb = new StringBuilder(2 + raw.length * 2);
sb.append("0x");
for (int i = 0; i < raw.length; i++) {
sb.append(String.format("%02X", Integer.valueOf(raw[i] & 0xFF)));
}
return sb.toString();
}
public static byte[] hexStringToByteArray(String hex)
{
Pattern replace = Pattern.compile("^0x");
String s = replace.matcher(hex).replaceAll("");
byte[] b = new byte[s.length() / 2];
for (int i = 0; i < b.length; i++){
int index = i * 2;
int v = Integer.parseInt(s.substring(index, index + 2), 16);
b[i] = (byte)v;
}
return b;
}
public static String byteArrayToBase64String(byte[] raw)
{
return new String(Base64Coder.encode(raw));
}
public static byte[] base64StringToByteArray(String str)
{
return Base64Coder.decode(str);
}
public static String base64_encode(String str)
{
return Base64Coder.encodeString(str);
}
public static String base64_decode(String str)
{
return Base64Coder.decodeString(str);
}
}
/*
* Base64Coder
*/
private static class Base64Coder
{
// The line separator string of the operating system.
private static final String systemLineSeparator = System.getProperty("line.separator");
// Mapping table from 6-bit nibbles to Base64 characters.
private static final char[] map1 = new char[64];
static {
int i=0;
for (char c='A'; c<='Z'; c++) map1[i++] = c;
for (char c='a'; c<='z'; c++) map1[i++] = c;
for (char c='0'; c<='9'; c++) map1[i++] = c;
map1[i++] = '+'; map1[i++] = '/';
}
// Mapping table from Base64 characters to 6-bit nibbles.
private static final byte[] map2 = new byte[128];
static {
for (int i=0; i<map2.length; i++) map2[i] = -1;
for (int i=0; i<64; i++) map2[map1[i]] = (byte)i;
}
/**
* Encodes a string into Base64 format.
* No blanks or line breaks are inserted.
* @param s A String to be encoded.
* @return A String containing the Base64 encoded data.
*/
public static String encodeString (String s)
{
return new String(encode(s.getBytes()));
}
/**
* Encodes a byte array into Base 64 format and breaks the output into lines of 76 characters.
* This method is compatible with <code>sun.misc.BASE64Encoder.encodeBuffer(byte[])</code>.
* @param in An array containing the data bytes to be encoded.
* @return A String containing the Base64 encoded data, broken into lines.
*/
public static String encodeLines (byte[] in)
{
return encodeLines(in, 0, in.length, 76, systemLineSeparator);
}
/**
* Encodes a byte array into Base 64 format and breaks the output into lines.
* @param in An array containing the data bytes to be encoded.
* @param iOff Offset of the first byte in <code>in</code> to be processed.
* @param iLen Number of bytes to be processed in <code>in</code>, starting at <code>iOff</code>.
* @param lineLen Line length for the output data. Should be a multiple of 4.
* @param lineSeparator The line separator to be used to separate the output lines.
* @return A String containing the Base64 encoded data, broken into lines.
*/
public static String encodeLines (byte[] in, int iOff, int iLen, int lineLen, String lineSeparator)
{
int blockLen = (lineLen*3) / 4;
if (blockLen <= 0) throw new IllegalArgumentException();
int lines = (iLen+blockLen-1) / blockLen;
int bufLen = ((iLen+2)/3)*4 + lines*lineSeparator.length();
StringBuilder buf = new StringBuilder(bufLen);
int ip = 0;
while (ip < iLen)
{
int l = Math.min(iLen-ip, blockLen);
buf.append (encode(in, iOff+ip, l));
buf.append (lineSeparator);
ip += l;
}
return buf.toString();
}
/**
* Encodes a byte array into Base64 format.
* No blanks or line breaks are inserted in the output.
* @param in An array containing the data bytes to be encoded.
* @return A character array containing the Base64 encoded data.
*/
public static char[] encode (byte[] in)
{
return encode(in, 0, in.length);
}
/**
* Encodes a byte array into Base64 format.
* No blanks or line breaks are inserted in the output.
* @param in An array containing the data bytes to be encoded.
* @param iLen Number of bytes to process in <code>in</code>.
* @return A character array containing the Base64 encoded data.
*/
public static char[] encode (byte[] in, int iLen)
{
return encode(in, 0, iLen);
}
/**
* Encodes a byte array into Base64 format.
* No blanks or line breaks are inserted in the output.
* @param in An array containing the data bytes to be encoded.
* @param iOff Offset of the first byte in <code>in</code> to be processed.
* @param iLen Number of bytes to process in <code>in</code>, starting at <code>iOff</code>.
* @return A character array containing the Base64 encoded data.
*/
public static char[] encode (byte[] in, int iOff, int iLen)
{
int oDataLen = (iLen*4+2)/3; // output length without padding
int oLen = ((iLen+2)/3)*4; // output length including padding
char[] out = new char[oLen];
int ip = iOff;
int iEnd = iOff + iLen;
int op = 0;
while (ip < iEnd)
{
int i0 = in[ip++] & 0xff;
int i1 = ip < iEnd ? in[ip++] & 0xff : 0;
int i2 = ip < iEnd ? in[ip++] & 0xff : 0;
int o0 = i0 >>> 2;
int o1 = ((i0 & 3) << 4) | (i1 >>> 4);
int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
int o3 = i2 & 0x3F;
out[op++] = map1[o0];
out[op++] = map1[o1];
out[op] = op < oDataLen ? map1[o2] : '='; op++;
out[op] = op < oDataLen ? map1[o3] : '='; op++;
}
return out;
}
/**
* Decodes a string from Base64 format.
* No blanks or line breaks are allowed within the Base64 encoded input data.
* @param s A Base64 String to be decoded.
* @return A String containing the decoded data.
* @throws IllegalArgumentException If the input is not valid Base64 encoded data.
*/
public static String decodeString (String s)
{
return new String(decode(s));
}
/**
* Decodes a byte array from Base64 format and ignores line separators, tabs and blanks.
* CR, LF, Tab and Space characters are ignored in the input data.
* This method is compatible with <code>sun.misc.BASE64Decoder.decodeBuffer(String)</code>.
* @param s A Base64 String to be decoded.
* @return An array containing the decoded data bytes.
* @throws IllegalArgumentException If the input is not valid Base64 encoded data.
*/
public static byte[] decodeLines (String s)
{
char[] buf = new char[s.length()];
int p = 0;
for (int ip = 0; ip < s.length(); ip++) {
char c = s.charAt(ip);
if (c != ' ' && c != '\r' && c != '\n' && c != '\t')
buf[p++] = c;
}
return decode(buf, 0, p);
}
/**
* Decodes a byte array from Base64 format.
* No blanks or line breaks are allowed within the Base64 encoded input data.
* @param s A Base64 String to be decoded.
* @return An array containing the decoded data bytes.
* @throws IllegalArgumentException If the input is not valid Base64 encoded data.
*/
public static byte[] decode (String s)
{
return decode(s.toCharArray());
}
/**
* Decodes a byte array from Base64 format.
* No blanks or line breaks are allowed within the Base64 encoded input data.
* @param in A character array containing the Base64 encoded data.
* @return An array containing the decoded data bytes.
* @throws IllegalArgumentException If the input is not valid Base64 encoded data.
*/
public static byte[] decode (char[] in)
{
return decode(in, 0, in.length);
}
/**
* Decodes a byte array from Base64 format.
* No blanks or line breaks are allowed within the Base64 encoded input data.
* @param in A character array containing the Base64 encoded data.
* @param iOff Offset of the first character in <code>in</code> to be processed.
* @param iLen Number of characters to process in <code>in</code>, starting at <code>iOff</code>.
* @return An array containing the decoded data bytes.
* @throws IllegalArgumentException If the input is not valid Base64 encoded data.
*/
public static byte[] decode (char[] in, int iOff, int iLen)
{
if (iLen%4 != 0) throw new IllegalArgumentException ("Length of Base64 encoded input string is not a multiple of 4.");
while (iLen > 0 && in[iOff+iLen-1] == '=') iLen--;
int oLen = (iLen*3) / 4;
byte[] out = new byte[oLen];
int ip = iOff;
int iEnd = iOff + iLen;
int op = 0;
while (ip < iEnd)
{
int i0 = in[ip++];
int i1 = in[ip++];
int i2 = ip < iEnd ? in[ip++] : 'A';
int i3 = ip < iEnd ? in[ip++] : 'A';
if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127)
throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
int b0 = map2[i0];
int b1 = map2[i1];
int b2 = map2[i2];
int b3 = map2[i3];
if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0)
throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
int o0 = ( b0 <<2) | (b1>>>4);
int o1 = ((b1 & 0xf)<<4) | (b2>>>2);
int o2 = ((b2 & 3)<<6) | b3;
out[op++] = (byte)o0;
if (op<oLen) out[op++] = (byte)o1;
if (op<oLen) out[op++] = (byte)o2;
}
return out;
}
// Dummy constructor.
private Base64Coder() {}
}
}
The modes of operation currently available are:
- OFB
- CBC
- CFB
- CTR
