DES（数据加密标准）是一种对称加密算法，下面分别给出Python、C、Java语言的DES代码示例。 ### Python实现 ```python from Crypto.Cipher import DES from Crypto.Util.Padding import pad, unpad from Crypto.Random import get_random_bytes # 密钥必须是8字节 key = get_random_bytes(8) cipher = DES.new(key, DES.MODE_ECB) # 待加密的明文 plaintext = b"Hello, DES!" # 填充明文以符合块大小 padded_plaintext = pad(plaintext, DES.block_size) # 加密 ciphertext = cipher.encrypt(padded_plaintext) # 解密 decipher = DES.new(key, DES.MODE_ECB) decrypted_data = decipher.decrypt(ciphertext) # 去除填充 original_plaintext = unpad(decrypted_data, DES.block_size) print(f"明文: {plaintext}") print(f"密文: {ciphertext}") print(f"解密后的明文: {original_plaintext}") ``` ### C语言实现 ```c #include <stdio.h> #include <stdlib.h> #include <string.h> // 这里只是简单示例，实际DES实现更复杂 // 假设已经有了DES的核心函数，这里只是一个框架 void des_encrypt(unsigned char *plaintext, unsigned char *key, unsigned char *ciphertext) { // 实际的DES加密逻辑 // 这里省略具体实现 memcpy(ciphertext, plaintext, strlen((char *)plaintext)); } void des_decrypt(unsigned char *ciphertext, unsigned char *key, unsigned char *plaintext) { // 实际的DES解密逻辑 // 这里省略具体实现 memcpy(plaintext, ciphertext, strlen((char *)ciphertext)); } int main() { unsigned char plaintext[] = "Hello, DES!"; unsigned char key[] = "12345678"; unsigned char ciphertext[100]; unsigned char decrypted[100]; des_encrypt(plaintext, key, ciphertext); des_decrypt(ciphertext, key, decrypted); printf("明文: %s\n", plaintext); printf("密文: %s\n", ciphertext); printf("解密后的明文: %s\n", decrypted); return 0; } ``` ### Java实现 ```java import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.spec.SecretKeySpec; import java.nio.charset.StandardCharsets; import java.util.Base64; public class DESExample { public static void main(String[] args) throws Exception { // 生成DES密钥 KeyGenerator keyGenerator = KeyGenerator.getInstance("DES"); keyGenerator.init(56); SecretKey secretKey = keyGenerator.generateKey(); byte[] keyBytes = secretKey.getEncoded(); SecretKeySpec secretKeySpec = new SecretKeySpec(keyBytes, "DES"); // 待加密的明文 String plaintext = "Hello, DES!"; byte[] plaintextBytes = plaintext.getBytes(StandardCharsets.UTF_8); // 创建加密器 Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding"); cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec); byte[] ciphertextBytes = cipher.doFinal(plaintextBytes); String ciphertext = Base64.getEncoder().encodeToString(ciphertextBytes); // 创建解密器 cipher.init(Cipher.DECRYPT_MODE, secretKeySpec); byte[] decryptedBytes = cipher.doFinal(ciphertextBytes); String decryptedText = new String(decryptedBytes, StandardCharsets.UTF_8); System.out.println("明文: " + plaintext); System.out.println("密文: " + ciphertext); System.out.println("解密后的明文: " + decryptedText); } } ```