今天调了下Java的RC4乱码，主要原因并不是byte问题，而是解密时编码问题。

import java.io.UnsupportedEncodingException;
public class RC4 {
    public static String decryptionRC4(byte[] data, String key) {
        if (data == null || key == null) {
            return null;
        }
        return new String(RC4Base(data, key));
    }
    public static byte[] encryptionRC4Byte(String data, String key) {
        if (data == null || key == null) {
            return null;
        }
        byte b_data[] = null;
		try {
			b_data = data.getBytes("UTF-8");
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
        return RC4Base(b_data, key);
    }
    private static byte[] initKey(String aKey) {
        byte[] b_key = null;
		try {
			b_key = aKey.getBytes("UTF-8");
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
        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 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;
    }
}