4 ms·

> An irrefutable cryptographic timestamp is just that, irrefutable. In math, sure, but he specifically asked about a court of law. Irrefutable in math doesn't

> An irrefutable cryptographic timestamp is just that, irrefutable. In math, sure, but he specifically asked about a court of law. Irrefutable in math doesn't mean admissible in court. Then there's the 1, 6, 12, or however many random people that decide the case; they likely need the math explained to them, and two sides get turns convincing them the other is wrong.

rosndo 5y ago
So uh, it’s like literally everything else in court? What’s the point here? This feels like such a strange line of thinking. > Irrefutable in math doesn't mean admissible in court What is that even supposed to mean? Why would (relevant) math not be admissible in court? Do you even know what these words mean? If cryptographic timestamps are relevant and not against the rules of evidence, obviously they are admissible.
- emmelaich 5y ago
  There was a case in Australia 10 or so years back, where MD5 sums were added to police speed camera photos. This was before MD5 vulnerabilities were well known. The defence successfully argued that MD5 was not totally reliable -- even though the chance of it being faked was absolutely tiny. The real irony was that without the MD5, the photos would probably have been accepted just on the police assertion of chain of custody. (I've been looking for this news story but unfortunately I can't find it at the moment) [edit- found it] https://www.schneier.com/blog/archives/2005/08/the_md5_defense.html https://www.schneier.com/blog/archives/2005/08/the_md5_defen... In fact the MD5 was known to be vulnerable - maybe. But it's still the case that adding MD5 made it less trustworthy!
  - miunau 5y ago
    Thanks for the link- exactly the sort of thing that I was looking for in feedback. I'm aware it's conjecture, but do you think this sort of precedence would be useful in airing doubts about the trustworthiness of an Ed25519 signature in court? Do you think the wording on the site is problematic in regards to this, or would you have any thoughts on how concerns about this would be best communicated?

rosndo 5y ago

So uh, it’s like literally everything else in court? What’s the point here? This feels like such a strange line of thinking. > Irrefutable in math doesn't mean admissible in court What is that even supposed to mean? Why would (relevant) math not be admissible in court? Do you even know what these words mean? If cryptographic timestamps are relevant and not against the rules of evidence, obviously they are admissible.

emmelaich 5y ago
There was a case in Australia 10 or so years back, where MD5 sums were added to police speed camera photos. This was before MD5 vulnerabilities were well known. The defence successfully argued that MD5 was not totally reliable -- even though the chance of it being faked was absolutely tiny. The real irony was that without the MD5, the photos would probably have been accepted just on the police assertion of chain of custody. (I've been looking for this news story but unfortunately I can't find it at the moment) [edit- found it] https://www.schneier.com/blog/archives/2005/08/the_md5_defense.html https://www.schneier.com/blog/archives/2005/08/the_md5_defen... In fact the MD5 was known to be vulnerable - maybe. But it's still the case that adding MD5 made it less trustworthy!
- miunau 5y ago
  Thanks for the link- exactly the sort of thing that I was looking for in feedback. I'm aware it's conjecture, but do you think this sort of precedence would be useful in airing doubts about the trustworthiness of an Ed25519 signature in court? Do you think the wording on the site is problematic in regards to this, or would you have any thoughts on how concerns about this would be best communicated?