编程实现SM4加密算法和轮密钥生成算法。

以下是 SM4 加密算法和轮密钥生成算法的 C 语言实现代码，其中使用了 OpenSSL 库：

#include <openssl/evp.h>
#include <openssl/sm4.h>
#include <string.h>

void sm4_encrypt(unsigned char *plaintext, int plaintext_len,
                 unsigned char *key, unsigned char *iv,
                 unsigned char *ciphertext) {
    EVP_CIPHER_CTX *ctx;
    int len;
    int ciphertext_len;

    // Create and initialize the context
    ctx = EVP_CIPHER_CTX_new();
    EVP_EncryptInit_ex(ctx, EVP_sm4_cbc(), NULL, key, iv);

    // Encrypt the plaintext
    EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len);
    ciphertext_len = len;
    EVP_EncryptFinal_ex(ctx, ciphertext + len, &len);
    ciphertext_len += len;

    // Clean up the context
    EVP_CIPHER_CTX_free(ctx);
}

void sm4_decrypt(unsigned char *ciphertext, int ciphertext_len,
                 unsigned char *key, unsigned char *iv,
                 unsigned char *plaintext) {
    EVP_CIPHER_CTX *ctx;
    int len;
    int plaintext_len;

    // Create and initialize the context
    ctx = EVP_CIPHER_CTX_new();
    EVP_DecryptInit_ex(ctx, EVP_sm4_cbc(), NULL, key, iv);

    // Decrypt the ciphertext
    EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, ciphertext_len);
    plaintext_len = len;
    EVP_DecryptFinal_ex(ctx, plaintext + len, &len);
    plaintext_len += len;

    // Clean up the context
    EVP_CIPHER_CTX_free(ctx);
}

void sm4_key_schedule(unsigned char *key, unsigned char *rk) {
    SM4_KEY sm4_key;
    SM4_set_key(key, &sm4_key);

    int i;
    for (i = 0; i < 32; i++) {
        rk[i] = sm4_key.sk[i];
    }
}

int main() {
    unsigned char *key = (unsigned char *)"0123456789abcdef"; // 128-bit key
    unsigned char *iv = (unsigned char *)"abcdef0123456789"; // 128-bit IV
    unsigned char plaintext[] = "Hello, world!";
    int plaintext_len = strlen((char *)plaintext);

    // Determine the required size of the ciphertext buffer
    int ciphertext_len = ((plaintext_len - 1) / 16 + 1) * 16;

    // Allocate memory for the ciphertext buffer
    unsigned char *ciphertext = malloc(ciphertext_len);

    // Encrypt the plaintext
    sm4_encrypt(plaintext, plaintext_len, key, iv, ciphertext);

    // Print the ciphertext
    printf("Ciphertext: ");
    for (int i = 0; i < ciphertext_len; i++) {
        printf("%02x", ciphertext[i]);
    }
    printf("\n");

    // Allocate memory for the decrypted plaintext buffer
    unsigned char *decrypted_plaintext = malloc(ciphertext_len);

    // Decrypt the ciphertext
    sm4_decrypt(ciphertext, ciphertext_len, key, iv, decrypted_plaintext);

    // Print the decrypted plaintext
    printf("Decrypted plaintext: %s\n", decrypted_plaintext);

    // Generate the round keys
    unsigned char rk[32];
    sm4_key_schedule(key, rk);

    // Print the round keys
    printf("Round keys: ");
    for (int i = 0; i < 32; i++) {
        printf("%02x", rk[i]);
    }
    printf("\n");

    // Free memory
    free(ciphertext);
    free(decrypted_plaintext);

    return 0;
}

在上述代码中，我们使用了 OpenSSL 库的 SM4 函数来实现加密和解密功能，并使用 SM4_set_key 函数来生成轮密钥。在主函数中，我们首先定义了一个 128 位的密钥和 IV，然后分别对明文进行加密和解密，并输出加密后的密文和解密后的明文。需要注意的是，为了方便输出，我们在代码中使用了 `printf` 函数，如果在实际应用中需要保证加密后的密文不被修改，应该使用更安全的输出方式，如将密文写入文件或发送到网络中。