Solution to Cryptochains

The given string 1DYsiB7a9hGWitCRky5wmN9ogeHKsVmNFF is a peculiar hash; one might note that it starts with 1 and is 34 characters long. It is a bitcoin address, which has some inbound and outbound transactions. Of note, the interesting transaction is bd4c44372669c8010dd63d9a900504df5b0d0852636aaf26c49151455f805791, which is goes from the given address to 18W97kXnWpS41Gbg8RMdEBayH51v2Cepee. That address has only one outbound transaction, to 1FzWnY7yNyb2kafG9es4BoFSdLMaRgXyaa, and so on, until the chain loops back to 1DYsiB7a9hGWitCRky5wmN9ogeHKsVmNFF. Each address in the chain ends in two identical letters, which would hopefully make the solver(s) suspicious. Taking either letter, the chain spells (separated with newlines for clarity):

Feathercoin6kW1y63PTRJCKHATVgYq3GyM6cei3RXGCC
LitecoinLUXny1MQ2rmGytGet4GUgeBJ38WiNFZdCC
PPcoinPCEUQvnuyQby3WjKUTxMmqSrZmiH4Uv2CC
DogecoinDLErpcttiCXjPs6mT2pfhHmGhDxdvqdJCC
RiecoinRHkfmHbTzaC152VKpprEfXcugDxMuGycCC
AuroracoinAVxBFKEfE1W3TrSRCmoYcDnvDrKSqYQNCC

The giant string has six substrings, each of which has the format (cryptocurrency)(starting address). Repeating the same chain finding process from above, the cryptocurrencies spell the following strings, respectively:

CrackThisMD55edc3bed517dbf9865fb815552c1eb21
CrackThisTigerc1f242dde1a689991e46261f145dac8d8fb9c8ca87d378a6
CrackThisEmptysaLt1kPBKDF28f72c23c1a832d5c62981ad2365e2416e156324c12ff77c8788d919e93b52468
CrackThisSHA25636c2c915463715bbee9b9e2f4c5e1d1e8af2fc2c97eeadf8d4ec1bdcf2f43542
CrackThisKeccak25641ffa5436c7d522a616a38b17955df447ec9bd3544b962fd7464d2f7938d8667
CrackThisSHA1a8dbbfa41cec833f8dd42be4d1fa9a13142c85c2

These new strings all start with CrackThis, and some are followed by common hash algorithms MD5 and SHA, which probably imply breaking the given hash with the algorithm. The complete mapping is as follows:

Coin	Hash Algorithm	Address
Feathercoin	MD5	5edc3bed517dbf9865fb815552c1eb21
Litecoin	Tiger	c1f242dde1a689991e46261f145dac8d8fb9c8ca87d378a6
PPcoin	EmptysaLt1kPBKDF2	8f72c23c1a832d5c62981ad2365e2416e156324c12ff77c8788d919e93b52468
Dogecoin	SHA256	36c2c915463715bbee9b9e2f4c5e1d1e8af2fc2c97eeadf8d4ec1bdcf2f43542
Riecoin	Keccak256	41ffa5436c7d522a616a38b17955df447ec9bd3544b962fd7464d2f7938d8667
Auroracoin	SHA1	a8dbbfa41cec833f8dd42be4d1fa9a13142c85c2

Note that EmptysaLt1k has inconsistent capitalization because all bitcoin-derived cryptocoin addresses use base 58, which means no lowercase l or capital I (or the number 0 or capital O, for that matter) to avoid confusion.

The efficient puzzle solver will input each address into a search engine before writing a dictionary attack for each hash. Luckily, the MD5, SHA256, and SHA1 hashes are searchable, which decrypt to fuckyou1, christy7, and password8, respectively. One notices that the passwords have the form (string)(number), where (number) is less than the length of (string). Thus, a good start for the dictionary attack for the rest of the hashes is to try common strings followed by a number between 1 and the length of the word. In fact, all words were drawn from the top 1000 common passwords. Python has easy-to-use libraries for tiger, pbkdf2, and keccak256. The resulting passwords are

Hash Algorithm	Password	Indexed Letter
MD5	fuckyou1	f
Tiger	laserjet5	r
PBKDF2	animal5	a
SHA256	christy7	y
Keccak256	farmer5	e
SHA1	password8	d

We can then index (number) into (string) to get a letter. The six letters form the answer, FRAYED.