下面是一个简单的C语言实现RSA加密算法的示例代码：
#include <stdio.h>#include <stdlib.h>#include <math.h>int gcd(int a, int b) { if (b == 0) return a; else return gcd(b, a % b);}int is_prime(int n) { if (n <= 1) return 0; for (int i = 2; i <= sqrt(n); i++) { if (n % i == 0) return 0; } return 1;}int generate_prime() { int p; do { p = rand() % 100 + 1; } while (!is_prime(p)); return p;}int mod_exp(int base, int exp, int mod) { int result = 1; while (exp > 0) { if (exp % 2 == 1) result = (result * base) % mod; base = (base * base) % mod; exp /= 2; } return result;}int main() { int p = generate_prime(); int q = generate_prime(); int n = p * q; int phi = (p - 1) * (q - 1); int e = 2; while (gcd(e, phi) != 1) { e++; } int d = 1; while ((d * e) % phi != 1) { d++; } printf("Public key: (%d, %d)\n", e, n); printf("Private key: (%d, %d)\n", d, n); int plaintext = 123; int ciphertext = mod_exp(plaintext, e, n); printf("Encrypted message: %d\n", ciphertext); int decrypted_text = mod_exp(ciphertext, d, n); printf("Decrypted message: %d\n", decrypted_text); return 0;}此代码生成两个随机素数p和q，计算n和phi的值，选择一个公钥e和私钥d，然后使用公钥对明文进行加密，使用私钥对密文进行解密。请注意，此处的加密和解密仅用于示例目的，实际应用中应该使用更大的素数和更复杂的操作。
