实验一、DES加密算法编程实验 ────────────────────────────────── 一、实验目标 理解 DES 的整体结构：Feistel 网络、16 轮迭代、子密钥生成。 掌握 DES 核心部件的编程实现：IP / IP⁻¹、E-扩展、S-盒、P-置换、PC-1 / PC-2、左右移位。 熟悉分组密码工作模式与填充方式：本实验采用「每 64 bit 一块 + PKCS5 填充」。 通过加/解密验证程序正确性，并能对单步结果进行人工比对。 ────────────────────────────────── 二、实验环境 • 语言：Python 3.8+（仅标准库 + binascii）。 • 编辑器：VS Code / PyCharm / Jupyter Notebook 均可。 • 操作系统：Windows / macOS / Linux 不限。 • 额外工具： – 十六进制查看器（HxD、xxd） – 在线 DES 计算器（验证用） ────────────────────────────────── 三、实验任务与步骤 任务 1：单步调试与日志分析 在 des

以下是实现 DES 加密算法编程实验的 Python 代码： ```python import binascii # IP 置换表 IP = [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] # IP⁻¹ 置换表 IP_inv = [40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31, 38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29, 36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27, 34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25] # E-扩展置换表 E = [32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 13, 14, 15, 16, 17, 18, 17, 18, 19, 20, 21, 22, 21, 22, 23, 24, 25, 26, 25, 26, 27, 28, 29, 30, 29, 30, 31, 32, 1, 2] # P-置换表 P = [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 置换表 PC1 = [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 置换表 PC2 = [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] # 左右移位表 shifts = [1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1] # S-盒 S_boxes = [ [ [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] ], [ [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] ], [ [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] ], [ [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] ], [ [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] ], [ [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] ], [ [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], [7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8] ], [ [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] ] ] def permute(block, table): """ 置换函数 :param block: 输入块 :param table: 置换表 :return: 置换后的块 """ return ''.join([block[i - 1] for i in table]) def left_shift(key, shift): """ 左移函数 :param key: 输入密钥 :param shift: 左移位数 :return: 左移后的密钥 """ return key[shift:] + key[:shift] def generate_subkeys(key): """ 生成 16 轮子密钥 :param key: 输入密钥 :return: 16 轮子密钥列表 """ key = bin(int(binascii.hexlify(key), 16))[2:].zfill(64) key = permute(key, PC1) C = key[:28] D = key[28:] subkeys = [] for i in range(16): C = left_shift(C, shifts[i]) D = left_shift(D, shifts[i]) CD = C + D subkey = permute(CD, PC2) subkeys.append(subkey) return subkeys def s_box_substitution(block): """ S-盒替换函数 :param block: 输入块 :return: 替换后的块 """ output = '' for i in range(8): sub_block = block[i * 6:(i + 1) * 6] row = int(sub_block[0] + sub_block[5], 2) col = int(sub_block[1:5], 2) s_box_output = bin(S_boxes[i][row][col])[2:].zfill(4) output += s_box_output return output def feistel_function(R, subkey): """ Feistel 函数 :param R: 右半部分 :param subkey: 子密钥 :return: Feistel 函数输出 """ E_R = permute(R, E) xor_result = bin(int(E_R, 2) ^ int(subkey, 2))[2:].zfill(48) s_box_output = s_box_substitution(xor_result) P_output = permute(s_box_output, P) return P_output def des_round(L, R, subkey, round_num): """ DES 一轮迭代 :param L: 左半部分 :param R: 右半部分 :param subkey: 子密钥 :param round_num: 轮数 :return: 新的左半部分和右半部分 """ if round_num == 5: # 选择第 5 轮进行单步调试 print(f"Round {round_num} Input:") print(f"L{i}: {L}") print(f"R{i}: {R}") E_R = permute(R, E) print(f"E(R{i}): {E_R}") xor_result = bin(int(E_R, 2) ^ int(subkey, 2))[2:].zfill(48) print(f"E(R{i}) XOR K{i}: {xor_result}") s_box_output = s_box_substitution(xor_result) print(f"S-Box Output: {s_box_output}") P_output = permute(s_box_output, P) [2025-11-09 22:06:30 | AI写代码神器 | 4096点数解答]