这些问题通常是由于加密和解密时使用的初始向量（IV）不同导致的。在使用MODE_CFB AES模式进行加密和解密时，请确保使用相同的IV。下面是一个C++示例，演示如何使用MODE_CFB进行加密和解密，并确保使用相同的IV：

#include 
#include 

int main() {
    const unsigned char key[] = "0123456789123456";
    const unsigned char iv[] = "0123456789123456";
    const unsigned char plaintext[] = "This is a secret message";
    const int plaintext_len = strlen((char*)plaintext);

    unsigned char ciphertext[plaintext_len];
    unsigned char decrypted_text[plaintext_len];

    AES_KEY aes_key;
    AES_set_encrypt_key(key, 128, &aes_key);

    AES_cfb128_encrypt(plaintext, ciphertext, plaintext_len, &aes_key, iv, NULL, AES_ENCRYPT);

    AES_set_decrypt_key(key, 128, &aes_key);

    AES_cfb128_decrypt(ciphertext, decrypted_text, plaintext_len, &aes_key, iv, NULL, AES_DECRYPT);

    std::cout << decrypted_text << std::endl;

    return 0;
}