Java RC4 加密解密

import java.io.UnsupportedEncodingException;

public class RC4 {

public static String decry_RC4(byte[] data, String key) {
if (data == null || key == null) {
return null;
}
return asString(RC4Base(data, key));
}

public static String decry_RC4(String data, String key) {
if (data == null || key == null) {
return null;
}
return new String(RC4Base(HexString2Bytes(data), key));
}

public static byte[] encry_RC4_byte(String data, String key) {
if (data == null || key == null) {
return null;
}
byte b_data[] = data.getBytes();
return RC4Base(b_data, key);
}

public static String encry_RC4_string(String data, String key) {
if (data == null || key == null) {
return null;
}
return toHexString(asString(encry_RC4_byte(data, key)));
}

private static String asString(byte[] buf) {
StringBuffer strbuf = new StringBuffer(buf.length);
for (int i = 0; i < buf.length; i++) {
strbuf.append((char) buf[i]);
}
return strbuf.toString();
}

private static byte[] initKey(String aKey) {
byte[] b_key = aKey.getBytes();
byte state[] = new byte[256];

for (int i = 0; i < 256; i++) {
state[i] = (byte) i;
}
int index1 = 0;
int index2 = 0;
if (b_key == null || b_key.length == 0) {
return null;
}
for (int i = 0; i < 256; i++) {
index2 = ((b_key[index1] & 0xff) + (state[i] & 0xff) + index2) & 0xff;
byte tmp = state[i];
state[i] = state[index2];
state[index2] = tmp;
index1 = (index1 + 1) % b_key.length;
}
return state;
}

private static String toHexString(String s) {
String str = "";
for (int i = 0; i < s.length(); i++) {
int ch = (int) s.charAt(i);
String s4 = Integer.toHexString(ch & 0xFF);
if (s4.length() == 1) {
s4 = '0' + s4;
}
str = str + s4;
}
return str;// 0x表示十六进制
}

private static byte[] HexString2Bytes(String src) {
int size = src.length();
byte[] ret = new byte[size / 2];
byte[] tmp = null;
try
{
tmp = src.getBytes(CHARSET);
}
catch (UnsupportedEncodingException e)
{
e.printStackTrace();
}
for (int i = 0; i < size / 2; i++) {
ret[i] = uniteBytes(tmp[i * 2], tmp[i * 2 + 1]);
}
return ret;
}

private static byte uniteBytes(byte src0, byte src1) {
char _b0 = (char)Byte.decode("0x" + new String(new byte[] { src0 }))
.byteValue();
_b0 = (char) (_b0 << 4);
char _b1 = (char)Byte.decode("0x" + new String(new byte[] { src1 }))
.byteValue();
byte ret = (byte) (_b0 ^ _b1);
return ret;
}

private static byte[] RC4Base (byte [] input, String mKkey) {
int x = 0;
int y = 0;
byte key[] = initKey(mKkey);
int xorIndex;
byte[] result = new byte[input.length];

for (int i = 0; i < input.length; i++) {
x = (x + 1) & 0xff;
y = ((key[x] & 0xff) + y) & 0xff;
byte tmp = key[x];
key[x] = key[y];
key[y] = tmp;
xorIndex = ((key[x] & 0xff) + (key[y] & 0xff)) & 0xff;
result[i] = (byte) (input[i] ^ key[xorIndex]);
}
return result;
}
}

public static void main(String[] args){
String inputStr = "中国1234";
String key = "3545C7B737D3D3223CA";
String str = encry_RC4_string(inputStr, key);
System.out.println(str);
System.out.println(decry_RC4(str, key));
}

9f5040d88613cf2765a6
中国1234