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E3 (Encrypt-Everything-Everywhere) is an easy-to-use open-source homomorphic encryption framework developed by the MoMA Lab at New York University Abu Dhabi. The framework provides C++ classes for supporting computation on private data. E3 is usability-oriented, allowing programmers to incorporate privacy to their programs without expertise in cryptography. In its first version, E3 encrypts variables using Fully Homomorphic Encryption and provides a rich set of C++ operators to the programmer.

Check out the E3 Wiki for more information about the framework and usage guides. For examples of programs that you can create with E3, check out the Tutorials Tab.

If you use our framework, please cite our paper titled "E3: A Framework for Compiling C++ Programs with Encrypted Operands", which can be found here: The paper describes the process of developing E3, as well as how to add new libraries to the framework.


Programming Features

E3 supports all the C++ operators (addition, subtraction, multiplication, division, comparison, bitwise operations), including division, a feature many frameworks currently do not support. E3 also provides flexibility and allows code reusability, as it enables users to operate with the same code on different FHE libraries or encryption schemes. In addition, E3 allows the integration with other root-of-trusts that emulate homomorphism.

Technical Features

E3 supports a big variety of Homomorphic Encryption libraries. This includes FHEW, HELib, SEAL, TFHE, as well as Paillier. Consequently, the framework also supports a number of schemes including BFV, BGV, CKKS, and GSW. It also provides support for two novel features, those of Bridging, and Batching.


A unique feature of E3 is bridging. This novel technique mixes different arithmetic abstractions, or, in other words mixes both Modular and Bit-level arithmetic in one program. This provides the ability to convert variables from integral type to modular, which eventually results in performance improvements of several orders of magnitude in certain cases. As a result, regarding the plaintext space E3 is capable of operating on both modular arithmetic and binary circuits.


E3 also fully supports batching capabilities as it allows for the parallel processing of plaintexts in a Single Instruction Multiple Data fashion, along with rotation operations. Regarding parameter selection methods, the user is required to manually select the parameters that will be used according to the application at hand. In addition, E3 automatically handles ciphertext relinearization and rescaling. Lastly,

Quick setup

Here we show how to set up and test E3 on Linux. For Windows and MacOS please check our wiki.


  • git
  • bash, sh
  • make (at least version 3.79.1)
  • a C++ compiler that supports C++17 (e.g. GCC ver >= 5.4.0)


  1. Clone E3:
git clone
  1. Compile:
cd e3/src


Let's test E3 by running a simple example that does some arithmetic.

  1. Create a directory anywhere you want. For this example, we will create a directory examples/hello_world at the root of E3:
mkdir -p examples/hello_world
  1. We need to create a configuration file to tell E3 which encryption scheme(s) and parameters to use. At examples/hello_world, create a file called cgt.cfg:
# this is a comment
# name : type (name is arbitrary, type: bridge, circuit, native, ring)
Secure : circuit
    encryption = tfhe # encryption library/scheme
    postfix = Ep # for encrypted constants >= 0
    postneg = En # for encrypted constants < 0
    sizes = 8 # plaintext bit-size

The configuration file we just wrote defines one FHE library to be used in the program: TFHE, which we named Secure. We can use any combination of FHE libraries schemes, including the same library with different parameters. The type 'circuit' works on bit-level arithmetic. E3 automatically creates three template classes for this type: SecureUint, SecureInt, and SecureBool. They are equivalent to unsigned int, int, and bool. We also defined the sizes of plaintexts that we will use in the program (8 bits).

  1. Now, let's write our program. Create a text file called main.cpp in examples/hello_world and add the following code:
#include <iostream>
#include "e3int.h"
#include "e3key.h" // includes support for decryption

using namespace std;

int main()
    // initializing variables
    SecureInt<8> a = _3_Ep, b = _2_En; // a = 3, b = -2;

    // homomorphic operations
    auto add = a + b;
    auto mul = a * b;

    // decrypting
    auto plain_a = e3::decrypt(a);
    auto plain_b = e3::decrypt(b);
    auto plain_add = e3::decrypt(add);
    auto plain_mul = e3::decrypt(mul);
    cout << plain_a << " + " << plain_b << " = " << plain_add << '\n';
    cout << plain_a << " * " << plain_b << " = " << plain_mul << '\n';
  1. To compile, go to 'e3/src':
make alice USER=../examples/hello_world
  1. Run:

You should see this:

3 + -2 = 1
3 * -2 = -6

For more advanced use, check E3 Wiki and tutorials.

Versions - Documentation: 20091618; Software: 20091711

Cite us:

E. Chielle, O. Mazonka, H. Gamil, N. G. Tsoutsos and M. Maniatakos, "E3: A Framework for Compiling C++ Programs with Encrypted Operands," Cryptology ePrint Archive, Report 2018/1013, 2018,

Eduardo Chielle, Oleg Mazonka, Homer Gamil, and Michail Maniatakos. 2022. Accelerating Fully Homomorphic Encryption by Bridging Modular and Bit-Level Arithmetic. In Proceedings of the 41st International Conference on Computer-Aided Design (ICCAD '22). Association for Computing Machinery, New York, NY, USA.

    author       = {Eduardo Chielle and
		    Oleg Mazonka and
		    Homer Gamil and
		    Nektarios Georgios Tsoutsos and
		    Michail Maniatakos},
    title        = {E3: A Framework for Compiling C++ Programs with Encrypted Operands},
    howpublished = {Cryptology ePrint Archive, Report 2018/1013},
    year         = {2018},
    note         = {\url{}},

    author = {Chielle, Eduardo and Mazonka, Oleg and Gamil, Homer and Maniatakos, Michail},
    title = {Accelerating Fully Homomorphic Encryption by Bridging Modular and Bit-Level Arithmetic},
    year = {2022},
    publisher = {Association for Computing Machinery},
    address = {New York, NY, USA},
    doi = {10.1145/3508352.3549415},
    booktitle = {Proceedings of the 41st International Conference on Computer-Aided Design},
    location = {San Diego, CA, USA},
    series = {ICCAD '22}

This software is under GPLv3 license

Copyright (C) 2022 NYUAD, MoMA lab


E3: Encrypt-Everything-Everywhere framework for compiling C++ programs with encrypted operands.







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