求个 java tea 加密转 python 的算法

2015-07-29 11:51:00 +08:00
 copyangle

java算法如下,可独立运行。怎奈小弟才疏学浅,有一段转换byte数组没看懂,哪位大侠能帮忙写个python版本,感激不尽~

package com.bmcc.service.pub.util;

/**
* Tea算法
* KEY为16字节,应为包含4个int型数的int[],一个int为4个字节
* 加密解密轮数应为8的倍数,推荐加密轮数为64轮
**/
public class Tea {
private int[] KEY = new int[] { //加密解密所用的KEY
1, 2, 3, 4 };
private String separatoradd = "0"; //加密字符串分隔符"+"

private String separatordel = "1"; //加密字符串分隔符"-"
//加密
private byte[] encrypt(
    byte[] content,
    int offset,
    int[] key,
    int times) { //times为加密轮数
    int[] tempInt = byteToInt(content, offset);
    int y = tempInt[0], z = tempInt[1], sum = 0, i;
    int delta = 0x9e3779b9; //这是算法标准给的值
    int a = key[0], b = key[1], c = key[2], d = key[3];

    for (i = 0; i < times; i++) {
        sum += delta;
        y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
        z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
    }
    tempInt[0] = y;
    tempInt[1] = z;
    return intToByte(tempInt, 0);
}
//解密
private byte[] decrypt(
    byte[] encryptContent,
    int offset,
    int[] key,
    int times) {
    int[] tempInt = byteToInt(encryptContent, offset);
    int y = tempInt[0], z = tempInt[1], sum = 0xC6EF3720, i;
    int delta = 0x9e3779b9; //这是算法标准给的值
    int a = key[0], b = key[1], c = key[2], d = key[3];

    for (i = 0; i < times; i++) {
        z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
        y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
        sum -= delta;
    }
    tempInt[0] = y;
    tempInt[1] = z;

    return intToByte(tempInt, 0);
}
//byte[]型数据转成int[]型数据
private int[] byteToInt(byte[] content, int offset) {

    int[] result = new int[content.length >> 2];
    for (int i = 0, j = offset; j < content.length; i++, j += 4) {
        result[i] =
            transform(content[j + 3]) | transform(content[j + 2])
                << 8 | transform(content[j + 1])
                << 16 | (int) content[j]
                << 24;
    }
    return result;

}
//int[]型数据转成byte[]型数据
private byte[] intToByte(int[] content, int offset) {
    byte[] result = new byte[content.length << 2];
    for (int i = 0, j = offset; j < result.length; i++, j += 4) {
        result[j + 3] = (byte) (content[i] & 0xff);
        result[j + 2] = (byte) ((content[i] >> 8) & 0xff);
        result[j + 1] = (byte) ((content[i] >> 16) & 0xff);
        result[j] = (byte) ((content[i] >> 24) & 0xff);
    }
    return result;
}
//若某字节被解释成负的则需将其转成无符号正数
private int transform(byte temp) {
    int tempInt = (int) temp;
    if (tempInt < 0) {
        tempInt += 256;
    }
    return tempInt;
}
//  通过TEA算法加密信息
public String encryptByTea(String info) {
    byte[] temp = info.getBytes();
    int n = 8 - temp.length % 8; //若temp的位数不足8的倍数,需要填充的位数
    byte[] encryptStr = new byte[temp.length + n];
    encryptStr[0] = (byte) n;
    System.arraycopy(temp, 0, encryptStr, n, temp.length);
    byte[] result = new byte[encryptStr.length];
    for (int offset = 0; offset < result.length; offset += 8) {
        byte[] tempEncrpt = encrypt(encryptStr, offset, KEY, 32);
        System.arraycopy(tempEncrpt, 0, result, offset, 8);
    }
    String tmp = encryptTwo(result);
    //      for (int i = 0; i < result.length; i++) {
    //          tmp = tmp + result[i] + this.separator;
    //      }
    return tmp;
}

private String encryptTwo(byte[] source) {
    String all = "";
    for (int i = 0; i < source.length; i++) {
        String tmp = this.separatoradd;
        int s = source[i];
        if (s < 0) {
            s = ~s + 1;
            tmp = this.separatordel;
        }
        String res = Integer.toHexString(s);
        if (res.length() == 1)
            res = "0" + res;
        all = all + res + tmp;
    }
    return all;
}

public byte[] decryptTwo(String res) {
    int k = 0;
    byte[] result = new byte[res.length() / 3];
    for (int i = 0, j = 3; i < res.length(); i = i + 3, j = i + 3) {
        String tmp = res.substring(i, j);
        if (this.separatoradd.charAt(0) == tmp.charAt(2))
            result[k++] = Byte.parseByte(tmp.substring(0, 2),16);
        else if (this.separatordel.charAt(0) == tmp.charAt(2))
            result[k++] = Byte.parseByte("-" + tmp.substring(0, 2),16);
    }
    return result;
}
//    通过TEA算法解密信息
public String decryptByTea(String info) {
    byte[] secretInfo = this.decryptTwo(info);
    byte[] decryptStr = null;
    byte[] tempDecrypt = new byte[secretInfo.length];
    for (int offset = 0; offset < secretInfo.length; offset += 8) {
        decryptStr = decrypt(secretInfo, offset, KEY, 32);
        System.arraycopy(decryptStr, 0, tempDecrypt, offset, 8);
    }
    int n = tempDecrypt[0];
    return new String(tempDecrypt, n, decryptStr.length - n);

}

public static void main(String[] args) {
    Tea tea = new Tea();
    String src ="abcd1234";
    String tmp = tea.encryptByTea(src);
    String result = tea.decryptByTea("2700304515a02c16411f06e14f17b14e16401c01c0591390");
    System.out.print("原数据:");
    System.out.println(src);
    System.out.print("加密后的数据:");
    System.out.println(tmp);
    System.out.print("解密后的数据:");
    System.out.println(result);
}

}

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copyangle
2015-07-29 13:49:39 +08:00
主要是 encryptByTea 这一段不明白,求解

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