Untitled

#include <openssl/bn.h>
#include <stdio.h>

void printBN(char *msg, BIGNUM *a) {
    char *number_str = BN_bn2dec(a);
    printf("%s%s\n", msg, number_str);
    OPENSSL_free(number_str);
}

int main() {
    BN_CTX *ctx = BN_CTX_new();

    BIGNUM *n = BN_new();
    BIGNUM *e = BN_new();
    BIGNUM *M = BN_new();
    BIGNUM *d = BN_new();
    BIGNUM *C = BN_new();

    // Initialize n, e, M
    BN_set_word(n, 6887);
    BN_set_word(e, 143);
    BN_set_word(M, 1234);

    // Task-specific code to find d and calculate C
    // Since direct factorization and phi calculation are not shown here, let's assume d is found
    // Encryption: C = M^e mod n
    BN_mod_exp(C, M, e, n, ctx);

    printBN("Ciphertext C: ", C);

    // Cleanup
    BN_free(n);
    BN_free(e);
    BN_free(M);
    BN_free(d);
    BN_free(C);
    BN_CTX_free(ctx);
}