# Fat Solutions

> Zero-knowledge research and development team building crypto privacy that people can actually use: confidential ERC20s, mixers, privacy pools, and privacy SDKs, from protocol design down to self-written provers.

Fat Solutions is a specialized R&D team focused on zero-knowledge (ZK) proofs and privacy engineering for the crypto ecosystem. The components of privacy already exist; our work is making them usable — taking the correct tradeoffs to move privacy from technical possibility to shipped products. We created Tongo (confidential ERC20s on Starknet) from scratch, we build the Tornado Cash SDK for the Ethereum Foundation's Kohaku initiative, and we helped design Kohaku's interface.

## What We Do

- Zero-knowledge proof system research and development, including custom provers
- Privacy protocol engineering (confidential ERC20s, mixers, privacy pools, private transfers)
- Privacy SDK engineering and wallet privacy integrations (Kohaku, Tornado Cash SDK, Privacy Pools SDK, Tongo SDK)
- ZK circuit development in Cairo, Noir, and Circom
- Cryptographic security research and ZK exploit analysis
- Privacy-first application development on Starknet, Aztec, and Miden

## Core Expertise

- ZK proof systems: Groth16, PLONK, STARKs, SNARKs, Bulletproofs
- Privacy protocols: Privacy Pools, confidential ERC20s, mixer protocols
- ZK programming languages: Cairo, Noir, Circom, Halo2
- Cryptographic primitives: ElGamal encryption, homomorphic encryption, range proofs, oblivious transfers
- Blockchain ecosystems: Starknet, Aztec, Miden, Ethereum, L2 rollups
- ZK security: circuit vulnerability research, proof system exploit analysis, trusted setup auditing

## Projects

### Kohaku (Ethereum Foundation)
Contributing to Kohaku, the Ethereum Foundation's open-source privacy and security framework for wallets and dapps. Fat Solutions builds developer-friendly SDKs (Tornado Cash SDK reimplementation, Privacy Pools v1 SDK, Tongo SDK) and helped design the Kohaku interface, lowering the barrier for privacy adoption across the Ethereum ecosystem.

### Tongo: Confidential ERC20s on Starknet
Confidential token standard powered by ElGamal encryption, range proofs, and Proof of Exponent. Users hold and transfer tokens with fully hidden balances, plus optional viewing keys for auditability and compliance.
- Website: https://tongo.cash
- Docs: https://docs.tongo.cash
- Source: https://github.com/fatlabsxyz/tongo

### Privacy Pools on Starknet (with 0xBow)
Porting the Privacy Pools protocol to Starknet, enabling private non-custodial asset transfers with association sets for compliance.

### Privacy Pools Core (with 0xBow)
Building and maintaining the SDK and Relayer for Privacy Pools, a protocol for private, non-lazarus asset transfers on Ethereum and L2s.
- Source: https://github.com/0xbow-io/privacy-pools-core

### Sumo Login: ZK Social Authentication
Zero-knowledge social login system using JWT proofs and account abstraction. Users access smart wallets with Web2 identities (Google, Discord) without seed phrases, using client-side ZK proofs on Starknet.
- Docs: https://sumologin.com
- Source: https://github.com/fatlabsxyz/sumo-login-cairo

### Miden Wallet Research
Research on integrating existing applications and wallets to onboard users to the Miden private execution environment.

### Terry Escape (Aztec/Noir)
Multiplayer private shared-state game using oblivious transfers, homomorphic encryption, and zero-knowledge proofs built with Noir on Aztec.
- Source: https://github.com/fatlabsxyz/terry-escape

## Research & Blog

We publish in-depth research on ZK security, circuit vulnerabilities, proof system exploits, and privacy protocol analysis. Topics include:

- ZK circuit bugs (under-constrained signals, missing bit-length checks, nondeterminism)
- Proof system vulnerabilities (broken Fiat-Shamir, verifier bugs, soundness failures)
- Trusted setup failures (toxic waste leaks, parameter misconfiguration)
- Protocol-level exploits across Tornado Cash, Zcash, Polygon zkEVM, Scroll zkEVM, Aztec, ZKSync
- Groth16, PLONK, and Bulletproofs vulnerability analysis
- Governance and operational security in privacy protocols

Blog: https://blog.fatsolutions.xyz

## Keywords and Topics

zero-knowledge, zk, zk-proofs, zkSNARKs, zkSTARKs, blockchain privacy, crypto privacy, privacy pools, confidential transactions, Tornado Cash, Monero, XMR, privacy coins, Starknet, Aztec, Miden, Cairo, Noir, Circom, Halo2, ElGamal, homomorphic encryption, range proofs, Groth16, PLONK, Bulletproofs, zk rollups, zkEVM, circuit security, zk audits, privacy research, privacy protocol development, DeFi privacy, Web3 privacy, account abstraction, zero-knowledge login, oblivious transfer, private state, private computation

## Contact

- Website: https://fatsolutions.xyz
- Email: root@fatsolutions.xyz
- Twitter/X: https://x.com/fatsolutionsxyz
- GitHub: https://github.com/fatlabsxyz