If you follow us on Twitter you might have noticed the tweet where we put together a puzzle and invited our followers to play. The prize was 1 million satoshi (0.01 BTC) waiting to be swept by anyone who managed to solve it first.
Then we sent a DM to anyone who decided to play:
There’s 1 million Non-KYC satoshis (0.01 BTC) buried in this image in a single P2PKH address waiting to be swept. They’re protected by a single private key which is hidden in this image somewhere. Are you able to find it ?
Hurry up because they’re not going to sit there forever.
When you manage to find and sweep the BTC, reply to the original tweet describing how you did it and how long it took.
Good luck! 🙂
What is it?
The image features 3 metal wallets from our recently released Coldbit Steel – 3x System Shock Bundle. You can use these Coldbit Steel wallets as a backup for your Bitcoin seeds. They’re made of stainless steel, they’re extremely heat and corrosion resistant. Ideal for long term, cold storage of your most valuable Bitcoin stash in geographically distributed locations.
Coldbit Steel – 3x System Shock Bundle
- 3 Coldbit Steel metal wallets
- you save 50 EUR
- each wallet stores up to 24 words (each word up to 8 letters)
- extra line that can store up to 16 letters for Wallet ID
- each of the 3 wallets has 2 stainless steel plates – heat and corrosion resistant (AISI 304)
- 4mm thick stamping plates and 2mm thick covers
- 2 nickel binding posts (countersink hole on the back – the wallet lays flat on the table)
- no loose parts
- 3 metal boxes for convenient storage
- 1x testing plate and a jig to practice stamping and provide support
Solving the puzzle started at around 11 AM CEST. To be honest we expected this puzzle to be solved in less than 2 hours but to our surprise 4 hours had passed and the coins were still there unclaimed.
As more and more people joined we started receiving questions about the way this puzzle was constructed.
At at 5:45 PM we sent out a hint:
This hint revealed 2 things:
- the public address containing 1 million sats 1Q7QWSMhQWdJ46o6MRPdtr7FLaDbwpaShq
- the signature confirming that we knew the private key for this address and that this was an actual puzzle and not some crypto Twitter scam
Knowing the public address would make solving this puzzle somewhat easier because one wouldn’t have to scan the entire pool of unused outputs looking for just one special P2PKH address containing 0.01 BTC matching our private key.
The other common dillema was whether the solution relied on steganography. Steganography is the practice of concealing a file, a message, image, or video within another file, message, image, or video. In other words was the private key protecting this address concealed somewhere in the binary stream of the image ?
Questions about steganography started popping up, the others were focused on tiny parts of the image thinking the answer is hidden in a tiny area. We didn’t want the players to waste more time figuring out fancy steganographic tools or using magnifying glasses so we tweeted some more hints:
7 hours after the puzzle started and still no winner in sight we decided to release the final hints:
“Call me Ishmael” is an opening line from Herman Melville’s novel “Moby-Dick”. It’s also the title of a blog post by BitMEX Research describing the exact same brainwallet setup used in this puzzle. You could find this blog post by searching for “Call me Ishmael Bitcoin” using your favourite search engine.
The reasoning behind giving out this hint was directing the players towards the exact wallet setup we used instead of letting them wonder about BIP39, wordlists, BIP32 and dozen other ways a Bitcoin wallet can be constructed.
There was another, subtle hint that this was a brainwallet setup:
Coldbit Steel – Bionic€82.00 – €104.00
Still, even knowing the exact setup, which was:
SHA256(‘Some secret passphrase’) = P2PKH compressed private key
wouldn’t guarantee solving this because “Some secret passphrase” was still unknown at this point. Obviously the answer was staring at you from the image, it only took your eyes, a clear head and some basic knowledge about P2PKH address construction to find it 🙂
Fortunately at 7:40 PM CEST we noticed the winning transaction sweeping all the funds to a Bech32 address. Was it the final tip “Call me Ishmael” hint we gave out or was it something else ?
At this point we didn’t know who swept the funds but at 8:02 PM we noticed this tweet from @6102bitcoin that confirmed the winner:
You can read more about solving this puzzle, the thought process and tools used from @6102bitcoin’s perspective here.
The solution to this puzzle was:
SHA256(“Cortez Shodan Bionic”) = compressed, private P2PKH key
These are the names of the characters from the System Shock videogame you see in the image. All it took was a little bit of research on the game, the steel wallets we have listed in our shop and some basic P2PKH address construction knowledge.
We love solving puzzles and Bitcoin is a perfect tool for constructing and solving them. Follow us on Twitter if you’d like to play next time we announce something similar. Hopefully you learned a thing or two reading this walk-through. Below are some resources you might find interesting to learn to be better prepared not just for solving puzzles but for making decisions and understanding the pros and cons of your specific wallet setup in general and brainwallets in particular. Personally we don’t use brainwallets, they’re not secure but they are an excellent substrate for constructing puzzles fun and engaging puzzles! 🙂