package com.*; 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 = src.getBytes(); 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 = "做个好男人"; String str = encry_RC4_string(inputStr, "123456"); System.out.println(str); System.out.println(decry_RC4(str, "123456")); } }
