# Nekryptology
Coinbase's advanced cryptography library, brought back from the dead and enhanced

## Differences from Kryptology
- Schnorr proofs are patched to use hash-to-curve, fixes a bug where depending on the curve there may be a small to very large percentage of proofs that are invalid encodings
- Supports BLS48-581 (uses MIRACL-generated implementation, slightly altered to align to curves.Scalar/curves.Point interfaces)
- Enhanced KOS15 implementation to support arbitrary computational and statistical security parameters
- Updated DKLs18 multiplication to use KOS15 enhancements
- OT-based t-of-n multiplication scheme (borrowed from DKLs19)
- Supports <=2048-bit IQC primitives (uses harmony-one's implementation, slightly adjusted to fix vulnerabilities in FS transform)
- Added Wesolowski VDF
- GG20 is removed

## Quickstart
Use the latest version of this library:

```
go get source.quilibrium.com/quilibrium/monorepo/nekryptology
```

## Documentation

Public documentations can be found at https://pkg.go.dev/source.quilibrium.com/quilibrium/monorepo/nekryptology

To access the documentation of the local version, run `godoc -http=:6060` and open
the following url in your browser.

http://localhost:6060/pkg/source.quilibrium.com/quilibrium/monorepo/nekryptology/

## Developer Setup
**Prerequisites**: `golang 1.18`, `make`

```
git clone git@source.quilibrium.com/quilibrium/monorepo/nekryptology.git && make 
``` 

## Components

The following is the list of primitives and protocols that are implemented in this repository.

### Curves

The curve abstraction code can be found at [pkg/core/curves/curve.go](pkg/core/curves/curve.go)

The curves that implement this abstraction are as follows.

- [BLS12377](pkg/core/curves/bls12377_curve.go)
- [BLS12381](pkg/core/curves/bls12381_curve.go)
- [BLS48581](pkg/core/curves/bls48581_curve.go)
- [Ed25519](pkg/core/curves/ed25519_curve.go)
- [Secp256k1](pkg/core/curves/k256_curve.go)
- [P256](pkg/core/curves/p256_curve.go)
- [Pallas](pkg/core/curves/pallas_curve.go)

### IQC

The IQC abstraction code can be found at [pkg/core/iqc/classgroup.go](pkg/core/iqc/classgroup.go).

### Protocols

The generic protocol interface [pkg/core/protocol/protocol.go](pkg/core/protocol/protocol.go).

- [Cryptographic Accumulators](pkg/accumulator)
- [Bulletproof](pkg/bulletproof)
- Oblivious Transfer
  - [Verifiable Simplest OT](pkg/ot/base/simplest)
  - [KOS OT Extension](pkg/ot/extension/kos)
- Threshold ECDSA Signature
  - [DKLs18 - DKG and Signing](pkg/tecdsa/dkls/v1)
  - GG20: The authors of GG20 have stated that the protocol is obsolete and should not be used. See [https://eprint.iacr.org/2020/540.pdf](https://eprint.iacr.org/2020/540.pdf).
    - [GG20 - DKG](pkg/dkg/gennaro)
    - [GG20 - Signing](pkg/tecdsa/gg20)
- Threshold Schnorr Signature
  - [FROST threshold signature - DKG](pkg/dkg/frost)
  - [FROST threshold signature - Signing](pkg/ted25519/frost)
- [Paillier encryption system](pkg/paillier)
- Secret Sharing Schemes
  - [Shamir's secret sharing scheme](pkg/sharing/shamir.go)
  - [Pedersen](pkg/sharing/pedersen.go)
  - [Feldman](pkg/sharing/feldman.go)
- [Verifiable encryption](pkg/verenc)
- [ZKP Schnorr](pkg/zkp/schnorr)


## Contributing
- [Versioning](https://blog.golang.org/publishing-go-modules): `vMajor.Minor.Patch`
    - Major revision indicates breaking API change or significant new features
    - Minor revision indicates no API breaking changes and may include significant new features or documentation
    - Patch indicates no API breaking changes and may include only fixes
 
 
## [References](docs/)
- [[GG20] _One Round Threshold ECDSA with Identifiable Abort._](https://eprint.iacr.org/2020/540.pdf)
- [[specV5] _One Round Threshold ECDSA for Coinbase._](docs/Coinbase_Pseudocode_v5.pdf)
- [[EL20] _Eliding RSA Group Membership Checks._](docs/rsa-membership.pdf) [src](https://www.overleaf.com/project/5f9c3b0624a9a600012037a3)
- [[P99] _Public-Key Cryptosystems Based on Composite Degree Residuosity Classes._](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.112.4035&rep=rep1&type=pdf)