Polkadot_Championship_Challenges

History

six ae2e29634a Prequalification challenge		2023-10-30 11:48:11 +04:00
..
README.md	Prequalification challenge	2023-10-30 11:48:11 +04:00

README.md

Implement Gandalf's blockchain

You need to reveal Gandalf's 8 words and create a chain of blocks with them: https://gandalf.lakera.ai/

Task is the create a local blockchain (no consensus/networking needed here):

Beat Gandalf AI game, find all the 8 words. Put them in order. Each one of them will be the data in your block.
Use | as delimiter between the words and the hash. Between the word and the hash, there is a - sign. - How this looks like: GENESIS|WORD1-HASH|WORD2-HASH|WORD3-HASH
Use SHA512 for the hashing algo. Start with the word and the delimiter and the first word: "GENESIS|WORD1-"
Make sure to calculate the dash sign into the next hash. It is part of the block data. You only add the hash from the previous block, not all data!
Everything is UPPERCASE.

If you are doing it correctly, you will have the following block hashes, starting from 0, Genesis: 0. 8288b35979d4e5dd5eee89a711ea5f41b04a17e7473a874c2b551844b57c0c24545cdbe7abf8e68dcd8da18a04ca8a1cc5798065ddb4fb32443136a589b3439d

3ee14c107bd6b3e050fac7b0a2ff42a474b10c789830d03f22cdf242a773905a88ac98ebcafdd2e8c0134c3fe285bb58f52f68a1d873290cf2430bb0b22429a7
058e7624f1d69625f1ecc4cdf41921fc7ffd31a38de10c9dab543986d68f47363974d2ea25832e6eacc5425afd685c11852fdd66793e7547dc9773cffb0431e8
2990022ea32e47959b83bb7faf36e430c046533da075ca6aabad7269891195480d86d9b76ac29b22268ef1ef419c147291b8ac9fea0f1b737dfce360be384764
ff0dd5196c836fb663b87aa0e8b647e0862646673f8b6eca3a38866e02290e02d95c94df83cd4be1ac3900f9e69d00c1d9ab5a30a5e4f6102a97d25eeab8ecf1
921be30124a505711224fb6de0955bd7e4c3b518aa4d5f65b6242c73fc1d4d978a8251c7d83f775aa14c00d01a5225085291c5df373a3bc18945b854d12e868f
This is secret! You need to insert the correct word plus the hash in order to count the final hash for the 7th block, which will be the flag.

Now that you solved Gandalf's game and wrote a local blockchain (without networking) it is time for the flag. Create the hash of block number 7 with the following data and hash it: "ICANHAZCHAIN-{PREVIOUS BLOCK}". The hash of this final block will be your flag.

The flag is the 7th block's sha512sum inserted into the PC{...} format. Pro tip: if you have issues with hash results, check with hexdump.

Keccak256: 0xdbd5381511b2b9b20ee59bcefcb7f76650030d20e99886fa03b3c3f5cef47d37

Challenge author: six