記錄一個java的RC4加密的方法

記錄一個java的RC4加密的方法：

import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.util.Base64;

public class RC4Util {
	
	public static void main(String[] args) throws UnsupportedEncodingException {
		String key = "Q5xEm3n7pNUKCYd6iSV214j9eXwWJBfZ";
		String chartSet = "utf-8";
		String data = String.valueOf(System.currentTimeMillis());
		String submit_key = Base64.getEncoder().encodeToString(RC4Util.HloveyRC4(data, key).getBytes(chartSet));
		System.out.println(submit_key);
	}
	public static String encryRC4String(String data, String key, String chartSet) throws UnsupportedEncodingException {
		if (data == null || key == null) {
			return null;
		}
		return toHexString(asString(encryRC4Byte(data, key, chartSet)));
	}

	public static byte[] encryRC4Byte(String data, String key, String chartSet) throws UnsupportedEncodingException {
		if (data == null || key == null) {
			return null;
		}
		if (chartSet == null || chartSet.isEmpty()) {
			byte bData[] = data.getBytes();
			return RC4Base(bData, key);
		} else {
			byte bData[] = data.getBytes(chartSet);
			return RC4Base(bData, key);
		}

	}

	public static String decryRC4(String data, String key) {
		if (data == null || key == null) {
			return null;
		}
		return new String(RC4Base(HexString2Bytes(data), key), StandardCharsets.UTF_8);
	}

	public static String decryRC4(byte[] data, String key) {
		if (data == null || key == null) {
			return null;
		}
		return asString(RC4Base(data, key));
	}

	private static String asString(byte[] buf) {
		StringBuffer strbuf = new StringBuffer(buf.length);
		for (byte b : buf) {
			strbuf.append((char) b);
		}
		return strbuf.toString();
	}

	private static byte[] initKey(String aKey) {
		byte[] bkey = 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 (bkey.length == 0) {
			return null;
		}
		for (int i = 0; i < 256; i++) {
			index2 = ((bkey[index1] & 0xff) + (state[i] & 0xff) + index2) & 0xff;
			byte tmp = state[i];
			state[i] = state[index2];
			state[index2] = tmp;
			index1 = (index1 + 1) % bkey.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;
	}

	private static byte[] HexString2Bytes(String src) {
		int size = src.length();
		byte[] ret = new byte[size / 2];
		byte[] tmp = src.getBytes(StandardCharsets.UTF_8);
		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();
		return (byte) (_b0 ^ _b1);
	}

	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;
	}
	/**
	 * 個人使用
	 * @param aInput
	 * @param aKey
	 * @return
	 */
	public static String HloveyRC4(String aInput,String aKey){   
        int[] iS = new int[256];   
        byte[] iK = new byte[256];   
        for (int i=0;i<256;i++)   
            iS[i]=i;   

        int j = 1;   
        for (short i= 0;i<256;i++){   
            iK[i]=(byte)aKey.charAt((i % aKey.length()));   
        }   
        j=0;   
        for (int i=0;i<255;i++){   
            j=(j+iS[i]+iK[i]) % 256;   
            int temp = iS[i];   
            iS[i]=iS[j];   
            iS[j]=temp;   
        }   
        int i=0;   
        j=0;   
        char[] iInputChar = aInput.toCharArray();   
        char[] iOutputChar = new char[iInputChar.length];   
        for(short x = 0;x<iInputChar.length;x++){   
            i = (i+1) % 256;   
            j = (j+iS[i]) % 256;   
            int temp = iS[i];   
            iS[i]=iS[j];   
            iS[j]=temp;   
            int t = (iS[i]+(iS[j] % 256)) % 256;   
            int iY = iS[t];   
            char iCY = (char)iY;   
            iOutputChar[x] =(char)( iInputChar[x] ^ iCY) ;      
        }   
        return new String(iOutputChar);   

    }
}