Slashdot Mirror
How a PhD Student Unlocked 1 Bitcoin Hidden In DNA (vice.com)
dmoberhaus writes: A 26-year-old Belgian PhD student named Sander Wuytz recently solved a 3-year-old puzzle that had locked the private key to 1 Bitcoin in a strand of synthetic DNA. Motherboard spoke with the student about how they managed to crack the puzzle, just days before it was set to expire. From the report: "As detailed by Nick Goldman, a researcher at the European Bioinformatics Institute, in his pioneering Nature paper on DNA storage, to encode information into DNA you take a text or binary file and rewrite it in base-3 (so rather than just ones and zeroes, there are zeroes, ones, and twos). This is then used to encode the data in the building blocks of life, the four nucleobases cytosine, thymine, adenine and guanine. As Wuyts explained to me, coding the data as nucleobases depended upon which nucleobase came before. So, for instance, if the previous base was adenine and the next pieces of data is a 0, it is coded as cytosine. If the next piece of data is a 1, it's coded as guanine, and so on. After the data is encoded as synthetic DNA fragments, these fragments are used to identify and read the actual files stored in the DNA. In the case of the Bitcoin challenge, there were a total of nine files contained in the DNA fragments. The files were encrypted with a keystream, which is a random series of characters that is included with the actual plain text message to obfuscate its meaning. The keystream code had been provided by Goldman in a document explaining the competition.
After running the code, Wuyts was able to combine the DNA fragments in the correct order to form one long piece of DNA. After working out some technical kinks, Wuyts was able to convert the DNA sequence into plain text, revealing the private key and unlocking the bitcoin (as well as some artefacts, including a drawing of James Joyce and the logo for the European Bioinformatics Institute). He had cracked the puzzle just five days before it was set to expire."
After running the code, Wuyts was able to combine the DNA fragments in the correct order to form one long piece of DNA. After working out some technical kinks, Wuyts was able to convert the DNA sequence into plain text, revealing the private key and unlocking the bitcoin (as well as some artefacts, including a drawing of James Joyce and the logo for the European Bioinformatics Institute). He had cracked the puzzle just five days before it was set to expire."
A bitcoin wallet consists of a private key and a public key. With the private key you can prove the wallet belongs to you and hence are able to start transactions.
The private key hidden in the DNA belongs to a wallet in which 1 bitcoin was deposited, as a reward for solving the puzzle. So with recovering the private key, this student can access the bitcoin.
I wondered that as well, but the choice seems deliberate. The PDF says a single "trit" is encoded as the difference between each nucleotide and the next in the sequence, explicitly to avoid sequences with repeated nucleotides. For any given nucleotide, there are only three possible non-repeating values. The PDF goes on to mention that every other segment is reverse-complemented, and that this choice of non-repeating was important in order to readily determine whether any particular segment had been reversed or not.