I solved a 0.5 ETH cryptographic puzzle on Ethereum, unsolved for 8 years, with the answer hiding in plain sight.
Three more of the same kind remain open, worth 2 ETH combined.
Three more of the same kind remain open, worth 2 ETH combined.
The puzzle is a TeikhosBounty contract, deployed in 2018.
The mechanic: the contract stores a masked ECDSA signature. Submit the right 64-byte public key, it verifies via ecrecover, and self-destructs sending you the ETH. The contract pays whoever solves it.
The mechanic: the contract stores a masked ECDSA signature. Submit the right 64-byte public key, it verifies via ecrecover, and self-destructs sending you the ETH. The contract pays whoever solves it.
This particular one had been attempted in 2022. The solver failed, but left the public key in calldata.
Four years later, that trace was still there. I recovered it, reconstructed the solution, and claimed the reward via a commit-reveal sequence last week.
Four years later, that trace was still there. I recovered it, reconstructed the solution, and claimed the reward via a commit-reveal sequence last week.
The three unsolved contracts hold 2 ETH total. Same mechanic, but no leaked calldata ; the public keys were never published.
etherscan.io/address/0x17e5…
etherscan.io/address/0xd7c6…
etherscan.io/address/0x973c…
etherscan.io/address/0x17e5…
etherscan.io/address/0xd7c6…
etherscan.io/address/0x973c…
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