DES_ofb64_encrypt
DES_ofb64_encrypt(in, out, (long)EVP_MAXCHUNK,
DES_ofb64_encrypt(in, out, (long)inl,
void DES_ofb64_encrypt(const unsigned char *in, unsigned char *out,
DES_ofb64_encrypt(in, out, (long)len, key, (DES_cblock *)ctx->iv, &num);
DES_ofb64_encrypt(in, out, MAXCHUNK, key, (DES_cblock *)ctx->iv, &num);
DES_ofb64_encrypt(&plain[i], &ofb_buf1[i], 1, &ks, &ofb_tmp, &num);
DES_ofb64_encrypt(ofb_buf1, ofb_buf2, sizeof(ofb_buf1), &ks, &ofb_tmp,