I Turned a Bitcoin Address Into an Ethereum Private Key — And It Led Me to Build a Crypto Collider

An experiment using a Bitcoin address as input for an Ethereum private key generation reveals a broader security concern: any arbitrary input can produce a valid private key, but valid does not mean secure. This insight led to building the Ktzchen Crypto Key Matching Collider, a Python-based research tool that systematically generates Bitcoin and Ethereum keys from arbitrary or weak inputs, checks real blockchain balances via nodes or APIs, and runs in parallel across multiple CPU cores. The core takeaway is that humans are poor at generating randomness, making wallets created from predictable or deterministic inputs theoretically reproducible — not because cryptography is broken, but because weak entropy undermines strong math.