Examples

OpenFHE provides the following examples which should provide the reader with a basic understanding of how to use the library for various purposes.

Boolean FHE

Boolean Fully Homomorphic Encryption Examples

At a high level:

• boolean.cpp: GINX (CGGI) Bootstrapping:

  • bootstrapping as described in TFHE: Fast Fully Homomorphic Encryption over the Torus and in Bootstrapping in FHEW-like Cryptosystems

• boolean-ap.cpp: AP (DM) Bootstrapping:

  • bootstrapping as described in FHEW: Bootstrapping Homomorphic Encryption in less than a second and in Bootstrapping in FHEW-like Cryptosystems

• boolean-lmkcdey.cpp: LMKCDEY Bootstrapping:

  • bootstrapping as described in Efficient FHEW Bootstrapping with Small Evaluation Keys, and Applications to Threshold Homomorphic Encryption

• boolean-serial-binary.cpp: Boolean Serialization:

  • serializing CryptoContext, various keys, and ciphertext to a file in binary format

• boolean-serial-json.cpp: Boolean Serialization - json:

  • serializing CryptoContext, various keys, and ciphertext to a file in json format

• boolean-truth-tables.cpp: Boolean Truth Tables:

  • prints out the truth tables for all supported binary gates

• eval-decomp.cpp: Eval Decomposition:

  • runs a homomorphic digit decomposition process on the input ciphertext

• eval-flooring.cpp: Eval Flooring:

  • rounds down the input ciphertext by certain number of bits

• eval-function.cpp: Eval Function:

  • evaluates a function f: Z_p -> Z_p on the input ciphertext

• eval-sign.cpp: Eval Sign:

  • evaluates the most-significant bit of the input ciphertext

Core

Core OpenFHE Examples:

• parallel.cpp:

  • provides an example of parallelization in OpenFHE with OpenMP

• sampling:

  • provides an example of doing integer Gaussian sampling using OpenFHE samplers.

  • For more information on sampling, read sampling documentation

PKE - SIMD FHE

SIMD Fully Homomorphic Encryption Examples:

Basic Homomorphic Encryption

Demonstrates basic homomorphic encryption using the various schemes:

• BFVrns (depth-bfvrns.cpp)

• BGVrns depth-bgvrns.cpp

Simple Mathematical Operations and Serialization

Demonstrates the following mathematical operations on vectors of appropriate type (integers in the case of BGV and BFV, and real numbers in CKKS):

• homomorphic additions,

• homomorphic multiplications

• homomorphic rotations

Additionally, we include the variants detailing how to do serialization-deserialization.

Schemes:

• Standard BGV-rns (simple-integers-bgvrns.cpp)

• BGV-rns with Serialization/Deserialization (simple-integers-serial-bgvrns.cpp)

• Standard BFV-rns (simple-integers.cpp)

• BFV-rns with Serialization/Deserialization (simple-integers-serial.cpp)

• Standard CKKS-rns (simple-real-numbers.cpp):

• CKKS-rns with Serialization/Deserialization (simple-real-numbers-serial.cpp)

Advanced CKKS Usage

Demonstates advanced operations on real-number vectors using CKKS:

• High-precision CKKS

• Rescaling (automatic and manual)

• hybrid key-switching

• hoisting

Formats

• Standard-precision Advanced CKKS Examples (advanced-real-numbers.cpp):

• High-precision Advanced CKKS Examples (advanced-real-numbers.cpp):

• CKKS Bootstrapping with Full Packing (simple-ckks-bootstrapping.cpp):

• CKKS Bootstrapping with Sparse Packing (advanced-ckks-bootstrapping.cpp):

Misc. Operations across Schemes

• rotation.cpp:

  • demonstrates use of EvalRotate automorphism for different schemes

• linearsum-evaluation:

  • demonstrates the process of taking the linear weighted sum of a vector of ciphertexts against a vector of plaintext data in the CKKS scheme

• polynomial-evaluation.cpp:

  • demonstrates an evaluation of a polynomial (power series) using CKKS

• pre-buffer.cpp:

  • demonstrates use of OpenFHE for encryption, re-encryption and decryption of packed vector of binary data

• threshold-fhe.cpp:

  • shows several examples of threshold FHE in BGVrns, BFVrns, and CKKSrns

• threshold-fhe-5p.cpp:

  • shows example of threshold FHE with 5 parties in BFVrns