🔐 ChaCha20-Hash - Lightweight Cryptographic Hash Function based on ChaCha20

ChaCha20-Hash is a novel cryptographic hash function inspired by the ChaCha20 stream cipher. This project explores how ChaCha20's internal permutation structure can be repurposed to create a secure, fast, and efficient hash function that meets modern cryptographic standards.

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📌 Table of Contents

• 📌 Table of Contents
• 🎯 Project Objective
• 🧠 Background & Motivation
• 🧱 Methodology
• ⚙️ Tech Stack
• 🧪 Evaluation Criteria
• 📊 Benchmarking Plan
• 📎 References

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🎯 Project Objective

• Develop a cryptographic hash function using ChaCha20's quarter-round transformations.
• Ensure core security properties:
  • Pre-image resistance
  • Collision resistance
  • Strong avalanche effect
• Implement and test the algorithm against standard cryptographic benchmarks.
• Compare performance with industry-standard hash functions like SHA-256, SHA-3, and BLAKE2.

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🧠 Background & Motivation

Modern cryptographic systems rely heavily on secure hash functions for integrity, authentication, and digital signatures.
ChaCha20 is a fast, secure stream cipher well-regarded in real-world applications (e.g., TLS, WireGuard, SSH). While not designed for hashing, its internal mixing structure offers promising properties for transformation-based hash design.

ChaCha20-Hash is an experimental design aimed at reusing ChaCha20's proven cryptographic core to explore a novel approach to hashing.

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🧱 Methodology

🔸 Design

• Use a sponge-like or HAIFA-inspired construction to process input blocks.
• Define input padding, state initialization, and output extraction.
• Use ChaCha20's core transformations (quarter-rounds, rotations) for state mixing.

🔸 Implementation

• Implemented in Python for prototyping; future optimization in Rust or C.
• Modular design:
  • Input pre-processing
  • ChaCha-based state transformation
  • Output extraction (e.g., 256-bit or 512-bit hash)

🔸 Testing

• Validate security properties:
  • Collision and pre-image resistance
  • Avalanche effect
• Perform randomness analysis using:
  • NIST STS
  • Dieharder
  • ENT

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⚙️ Tech Stack

Component	Technology
Language	Python (prototype), Rust or C (optimized)
Crypto Library	PyCryptodome / RustCrypto / Custom
Testing Tools	NIST STS, Dieharder, ENT
Documentation	Markdown, LaTeX (reporting)
Version Control	Git + GitHub

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🧪 Evaluation Criteria

Property	Evaluation Method
Collision Resistance	Attempted collision generation
Pre-image Resistance	Reversibility testing
Avalanche Effect	Bit-flip + Hamming distance analysis
Output Uniformity	Entropy and frequency tests
Performance	Throughput in MB/s

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📊 Benchmarking Plan

• Compare ChaCha20-Hash against:
  • SHA-256
  • SHA-3
  • BLAKE2b
• Metrics:
  • Speed (MB/s)
  • Hash uniformity
  • Output entropy
  • Memory usage

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📎 References

• Bernstein, D. J. (2008). ChaCha: A variant of Salsa20
• RFC 8439 – ChaCha20 and Poly1305 for IETF protocols
• Biham, E., & Dunkelman, O. (2007). The HAIFA construction
• NIST SP 800-22 – Statistical Testing Suite (STS)
• Keccak Team – Sponge construction