static int aes_cfb8_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
                           const unsigned char *in, size_t len)
{
    EVP_AES_KEY *dat = (EVP_AES_KEY *) ctx->cipher_data;

    CRYPTO_cfb128_8_encrypt(in, out, len, &dat->ks,
                            ctx->iv, &ctx->num, ctx->encrypt, dat->block);
    return 1;
}
static int aes_cfb8_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
                           const unsigned char *in, size_t len)
{
    EVP_AES_KEY *dat = (EVP_AES_KEY *) ctx->cipher_data;

    CRYPTO_cfb128_8_encrypt(in, out, len, &dat->ks,
                            ctx->iv, &ctx->num, ctx->encrypt, dat->block);
    return 1;
}