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 Android教程網 >> Android技術 >> 關於Android編程 >> Android/java源代碼實現DES算法原理+整理

Android/java源代碼實現DES算法原理+整理

編輯:關於Android編程

1.初始置換/IP置換

// 初始置換表
	private static final int[] IP_Table = { 58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46,
			38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11,
			3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7 };
注意:IP置換表裡的數據表示的是64位原始數據的位置/下標,不是值!!

 

使用java表示初始置換

 

                int[] M = new int[64];//IP置換後的數據
		for (i = 0; i < 64; i++) {
			M[i] = timeData[IP_Table[i] - 1];// 明文數據初始置換(IP置換)
		}//int[] timeData是64位二進制原始數據

2.函數f過程

 

初始化各個常量數據

 

// 擴展置換E表
	private static final int[] E_Table = { 32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 12, 13, 14, 15,
			16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1 };
	// P-盒置換
	private static final int[] P_Table = { 16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10, 2, 8, 24, 14,
			32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25 };
	// PC-1
	private static final int[] PC_1 = { 57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35, 27,
			19, 11, 3, 60, 52, 44, 36, 63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29,
			21, 13, 5, 28, 20, 12, 4 };
	// PC-2
	private static final int[] PC_2 = { 14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12, 4, 26, 8, 16, 7, 27, 20,
			13, 2, 41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48, 44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32 };
	// 循環左移位數表
	private static final int[] LOOP_left = { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 };
	// S-盒1
	private static final int S_Box1[][] = { { 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7 },
			{ 0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8 },
			{ 4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0 },
			{ 15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13 } };
	// S2
	private static final int S_BOX2[][] = { { 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10 },
			{ 3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5 },
			{ 0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15 },
			{ 13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9 } };
	// S3
	private static final int S_BOX3[][] = { { 10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8 },
			{ 13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1 },
			{ 13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7 },
			{ 1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12 } };
	// S4
	private static final int S_BOX4[][] = { { 7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15 },
			{ 13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9 },
			{ 10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4 },
			{ 3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14 } };
	// S5
	private static final int S_BOX5[][] = { { 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9 },
			{ 14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6 },
			{ 4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14 },
			{ 11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3 } };
	// S6
	private static final int S_BOX6[][] = { { 12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11 },
			{ 10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8 },
			{ 9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6 },
			{ 4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13 } };
	// S7
	private static final int S_BOX7[][] = { { 4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1 },
			{ 13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6 },
			{ 1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2 },
			{ 6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12 } };
	// S8
	private static final int S_BOX8[][] = { { 13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7 },
			{ 1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2 },
			{ 7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8 },
			{ 2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11 } };
	private static final int[][][] S_BOX = { S_Box1, S_BOX2, S_BOX3, S_BOX4, S_BOX5, S_BOX6, S_BOX7, S_BOX8 };

2.1 秘鑰置換--字秘鑰的生成

 

 

 

/**
	 * 循環左移
	 * 
	 * @param k
	 *            子密鑰
	 * @param offset
	 *            循環左移的位數
	 */
	private void LeftBitMove(int[] k, int offset) {
		int i;
		int[] c0 = new int[28];
		int[] d0 = new int[28];
		int[] c1 = new int[28];
		int[] d1 = new int[28];
		for (i = 0; i < 28; i++) {
			c0[i] = k[i];
			d0[i] = k[i + 28];
		}
		if (offset == 1) {// 循環左移1位
			for (i = 0; i < 27; i++) {
				c1[i] = c0[i + 1];
				d1[i] = d0[i + 1];
			}
			c1[27] = c0[27];
			d1[27] = d0[27];
		} else if (offset == 2) {// 循環左移2位
			for (i = 0; i < 26; i++) {
				c1[i] = c0[i + 2];
				d1[i] = d0[i + 2];
			}
			c1[26] = c0[0];
			d1[26] = d0[0];
			c1[27] = c0[1];
			d1[27] = d0[1];
		}
		for (i = 0; i < 28; i++) {
			k[i] = c1[i];
			k[i + 28] = d1[i];
		}
	}

/**
	 * 初始化子密鑰
	 * 
	 * @param key
	 *            56位密鑰
	 * @param keyarray
	 *            子密鑰數組
	 */
	private void KeyInitialize(int[] key, int[][] keyarray) {
		int i;
		int j;
		int[] K0 = new int[56];
		for (i = 0; i < 56; i++) {// PC_1置換
			K0[i] = key[PC_1[i] - 1];
		}
		for (i = 0; i < 16; i++) {// 進行十六次,分別得到16個子密鑰
			LeftBitMove(K0, LOOP_left[i]);// 循環左移
			for (j = 0; j < 48; j++) {// 循環左移之後進行PC_2置換得到子密鑰
				keyarray[i][j] = K0[PC_2[j] - 1];// 生成16個48位的子密鑰
			}
		}
	}

2.2 擴展置換E(E位選擇表)+S盒置換+P盒置換

 

 

/**
	 * 
	 * @param M
	 *            64位經過IP置換後的明文數據
	 * @param times
	 *            迭代輪數
	 * @param flag
	 *            1為加密
	 * @param keyarray
	 *            子密鑰數組
	 */
	private void functionF(int[] M, int times, int flag, int[][] keyarray) {
		int i;
		int j;
		int x = 0;
		int y = 0;
		int[] L0 = new int[32];
		int[] R0 = new int[32];
		int[] L1 = new int[32];
		int[] R1 = new int[32];
		int[] RE = new int[48];// E擴展置換之後並且與子密鑰異或運算得到48位數據
		int[][] S = new int[8][6];// S盒輸入數據8組6位
		// S盒數據是6位輸入,4位輸出
		int[] sBoxData = new int[8];
		int[] sValue = new int[32];
		int[] RP = new int[32];
		for (i = 0; i < 32; i++) {// 將明文分成左右兩部分
			L0[i] = M[i];
			R0[i] = M[i + 32];
		}
		for (i = 0; i < 48; i++) {// 右半部份進行擴展E置換,得到48位RE
			RE[i] = R0[E_Table[i] - 1];
			RE[i] = RE[i] + keyarray[times][i];// 與子密鑰按位做不進位加法運算(R0和子密鑰做異或運算)
			if (RE[i] == 2) {
				RE[i] = 0;
			}
		}
		for (i = 0; i < 8; i++) {
			for (j = 0; j < 6; j++) {
				S[i][j] = RE[(i * 6) + j];
			} // 把擴展之後的數據分成8組6位的數組
			//在上一篇講到,S盒的計算方法,例如Data = D0D1D2D3D4D5(十進制);則對應的S盒行是D0D5的值,對應的S盒列是D1D2D3D4的值。
			//所以行=D0D5,用二進制表示是D0*2+D1*1等價於(D0<<1)+D5
			//列=D1D2D3D4,用二進制表示是(D1*8+D2*4+D3*2+D4*1)等價於((D1<<3)+(D2<<2)+(D3<<1)+D4)
			//注意左移運算要用括號包圍起來,因為存在運算優先級,如果沒有使用括號,會運算出錯
			x = (S[i][0] << 1) + S[i][5];
			y = (S[i][1] << 3) + (S[i][2] << 2) + (S[i][3] << 1) + (S[i][4]);
			sBoxData[i] = S_BOX[i][x][y];// 經過S盒得到8個十進制數字
			for (j = 0; j < 4; j++) {// 把十進制數字轉成4位二進制
				sValue[(i * 4 + 3) - j] = sBoxData[i] % 2;
				sBoxData[i] = sBoxData[i] / 2;
			}
		} // 經過S盒得到32位數組
		for (i = 0; i < 32; i++) {
			RP[i] = sValue[P_Table[i] - 1];// P盒置換得到數組就是函數f最終數組
			// 左右進行交換
			L1[i] = R0[i];
			R1[i] = L0[i] + RP[i];
			if (R1[i] == 2) {
				R1[i] = 0;
			}
			// 注意最後一次和第一次變換時,左右不進行交換
			if ((flag == 0) && (times == 0) || ((flag == 1) && (times == 15))) {// 第一次和最後一次再交換一次實現不變
				M[i] = R1[i];
				M[i + 32] = L1[i];
			} else {
				M[i] = L1[i];
				M[i + 32] = R1[i];
			}
		}
	}
注意:左移運算和循環左移是不一樣的概念!!

 

3. IP置換+函數F+逆置換

 

 

/**
	 * IP置換+函數F+逆置換
	 * @param timeData
	 * @param flag
	 * @param keyarray
	 * @return
	 */
	private byte[] Encrypt(int[] timeData, int flag, int[][] keyarray) {
		int i = 0;
		int[] M = new int[64];
		int[] MIP_1 = new int[64];
		byte[] encrypt = new byte[8];
		for (i = 0; i < 64; i++) {
			M[i] = timeData[IP_Table[i] - 1];// 明文數據初始置換(IP置換)
		}
		if (flag == 1) {// 加密
			for (i = 0; i < 16; i++) {
				functionF(M, i, flag, keyarray);
			}
		} else if (flag == 0) {// 解密:在上一篇說過,DES算法加密和解密可以使用相同的算法。加密和解密唯一不同的是秘鑰的次序是相反的
			for (i = 15; i >= 0; i--) {
				functionF(M, i, flag, keyarray);
			}
		}
		// 逆運算
		for (i = 0; i < 64; i++) {
			MIP_1[i] = M[IPR_Table[i] - 1];
		}
		// 返回加密數據
		GetEncryptResultOfByteArray(MIP_1, encrypt);
		return encrypt;

	}

 

 

4. 其它輔助方法
/**
	 * 將64位二進制數據的數組轉換成為8個整數
	 * 
	 * @param data
	 * @param value
	 */
	private void GetEncryptResultOfByteArray(int[] data, byte[] value) {
		int i, j;
		for (i = 0; i < 8; i++) {
			for (j = 0; j < 8; j++) {// i*8等價於i<<3
				value[i] += data[i * 8 + j] << (7 - j);// 每位二進制數據乘於2的(7-j)次方,就是每位二進制左移(7-j)
			}
		}
		// 如果絕對值大於255則是負數
		for (i = 0; i < 8; i++) {
			value[i] %= 256;
			if (value[i] > 128) {
				value[i] -= 255;
			}
		}
	}

/**
	 * 格式化字節數組,添加填充位
	 * @param data
	 * @param flag
	 * @return
	 */
	private byte[] ByteDataFormat(byte[] data, int flag) {
		int len = data.length;
		int padlen = 8 - (len % 8);
		int newlen = len + padlen;// 8的倍數長度
		byte[] newdata = new byte[newlen];
		System.arraycopy(data, 0, newdata, 0, len);
		for (int i = len; i < newlen; i++) {// 易錯點,i=len
			newdata[i] = (byte) padlen;//隨意填充任何值,不一定非要padlen
		}
		return newdata;
	}

        int[] keydata = new int[64];// 二進制加密數據
	int[] encryptdata = new int[64];// 加密操作完成後的字節數據
	byte[] EncrypeCode = new byte[8];// 密鑰初始化成二維數組
	int[][] KeyArray = new int[16][48];// 將密鑰字節數組轉換成二進制字節數組
	byte[] bytekey;
public MyDES() {
		String key = "abcdefgh";
		String data = "qwertyui";
//		key = "原始秘鑰";
		// data = "原始數據";
		this.bytekey = key.getBytes();
		MyUtils.log("加密前明文:" + data);
		byte[] result = DesEncrypt(data.getBytes(), 1);
		MyUtils.log("加密後密文:" + new String(result));
		MyUtils.log("解密後明文:" + new String(DesEncrypt(result, 0)));
	}

	private byte[] DesEncrypt(byte[] des_data, int flag) {
		byte[] format_key = ByteDataFormat(bytekey, flag);
		byte[] format_data = ByteDataFormat(des_data, flag);
		int datalen = format_data.length;
		int unitcount = datalen / 8;
		byte[] result_data = new byte[datalen];
		for (int i = 0; i < unitcount; i++) {
			byte[] tmpkey = new byte[8];
			byte[] tmpdata = new byte[8];
			System.arraycopy(format_key, 0, tmpkey, 0, 8);
			System.arraycopy(format_data, i * 8, tmpdata, 0, 8);
			byte[] tmpresult = UnitDes(tmpkey, tmpdata, flag);
			System.arraycopy(tmpresult, 0, result_data, i * 8, 8);
		}
		byte[] decryptbytearray = null;
		if (flag == 0) {// 解密
			int total_len = datalen;
			int delete_len = result_data[total_len - 8 - 1];
			delete_len = ((delete_len >= 1) && (delete_len <= 8)) ? delete_len : 0;
			decryptbytearray = new byte[total_len - delete_len - 8];
			boolean del_flag = true;
			for (int k = 0; k < delete_len; k++) {
				if (delete_len != result_data[total_len - 8 - (k + 1)]) {
					del_flag = false;
				}
			}
			if (del_flag) {
				System.arraycopy(result_data, 0, decryptbytearray, 0, total_len - delete_len - 8);
			}
		}
		return (flag == 1) ? result_data : decryptbytearray;
	}

	/**
	 * @return
	 */
	private byte[] UnitDes(byte[] des_key, byte[] des_data, int flag) {
		if ((des_key.length != 8) || (des_data.length != 8) || ((flag != 0) && (flag != 1))) {// 檢測輸入參數格式是否正確,錯誤直接返回空值null
			throw new RuntimeException("Data Format Error!");
		}
		int flags = flag;
		int[] keydata = new int[64];// 二進制加密密鑰
		int[] encryptdata = new int[64];// 二進制加密數據
		byte[] EncryptCode = new byte[8];// 加密操作完成後的字節數組
		int[][] KeyArray = new int[16][48];// 密鑰初始化成二維數組
		keydata = ReadDataToBinnaryIntArray(des_key);// 將密鑰字節數組轉換成二進制
		encryptdata = ReadDataToBinnaryIntArray(des_data);// 將加密數據字節數組轉換成二進制字節數組
		KeyInitialize(keydata, KeyArray);// 初始化密鑰為二位密鑰數組
		EncryptCode = Encrypt(encryptdata, flags, KeyArray);// 執行加密解密操作
		return EncryptCode;
	}

5.運行結果
\\

注意:秘鑰和數據都要64位的。1個字節=8位,1個字母=1個字節,1個漢字=2個字節。

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