3 ms·

For a shorter executive summary, what does "broke" mean here? Can you reliably produce collisions now for 92% of SHA-256 digests?

• logicallee 7mo ago
  No, or we would have said so. It means that by relaxing the equations schedule somewhat, we are able to find a pair of differing messages that produce the same digest. However, we only relax the schedule a little bit, we still enforce 59 out of 64 schedule equations through the full 64 rounds - which is why we're only 92% of the way through to breaking it and not 100% of the way as we are with MD5. Importantly, we are not yet implementing the most advanced technique of Wang-style message modification, and we therefore expect that someone will be able to satisfy all 64 equations soon. This could result in an actual full-schedule, full-round collision. The previous record was only just 39 rounds out of 64 rounds, leaving 25 rounds, usually each of which mixes the message up completely. As mentioned in the paper, this attacks the problem from a different direction.
  • kstrauser 7mo ago
    I don't believe a word of this.
    • logicallee 7mo ago
      I mean, sure, you're free to wait until some team has a full collision, or free to believe it'll never happen. We've just published what we've done so far and our expectations for future directions. You can say you don't think that'll happen, it's fine.