RC2_ofb64_encrypt
RC2_ofb64_encrypt(in, out, (long)chunk, &((EVP_RC2_KEY *)ctx->cipher_data)->ks, ctx->iv, &ctx->num);
RC2_ofb64_encrypt(in, out, (long)inl, &((EVP_RC2_KEY *)ctx->cipher_data)->ks, ctx->iv, &ctx->num);
void RC2_ofb64_encrypt(const unsigned char *in, unsigned char *out,