Thread by @peterktodd

The latest hoopla about the Bitcoin blockchain potentially containing small amounts of "illegal data", is a good opportunity for early career security researcher to write a tool to insert and retrieve arbitrary data from certificate transparency logs.

Easy w/ @letsencrypt

Most obvious way to do it is via the DNS name; more clever would be to encode data in the pubkey. Might be other fields as well that you can use.

If the relevant CT log authorities are crazy enough to delete the data (specifically, make it not available to the public), it immediately destroys the entire auditability of CT.

For CT this is actually an easily avoidable problem: they could have used a merklized k:v index.

W/ that design, you can selectively delete and only destroy the auditability of the CT chain for *some* domain names.

Other fun illegal data targets:

Tor consensus,
Git repository (can add hidden data to commits - how @opentimestamps works!),
Mailing lists (steganographically encode, so replies that quote your email are also "contaminated"),
PGP key servers/@KeybaseIO,
trusted setup ceremonies?

Even more:

Free media like photos, music, etc. that's likely to get Incorporated into other works (not a novel problem!),
Scientific observations (e.g. inject encoded noise into a radio astronomy telescope),
Public safety related radio (e.g. encoded noise on airline frequencies)

...and for bored billionaires: encode messages into stock market price movements. 😁

Or if you're Jewish, the weather - according to council member Trayon White. :/