3 ms·
I did a bit of a deep dive into this, in case anyone is interested. I think reading the code is a great way to understand _why_ this vulnerability happened: ht
by e79 2y ago
I did a bit of a deep dive into this, in case anyone is interested. I think reading the code is a great way to understand _why_ this vulnerability happened:
https://ericrafaloff.com/your-putty-generated-nist-p-521-keys-are-compromised/ https://ericrafaloff.com/your-putty-generated-nist-p-521-key...
- ki85squared 2y agoThank you. Your writeup helped make it click!
- Elucalidavah 2y agoYour title says "PuTTY-Generated" but the OP article says "The problem is not with how the key was originally generated; it doesn't matter whether it came from PuTTYgen or somewhere else. What matters is whether it was ever used with PuTTY or Pageant".
- e79 2y agoGood catch! I wrote the title before I had dug into the matter and forgot to update it. Thanks for pointing that out. Any k generation and subsequent signature generation are going to be impacted.
- Aachen 2y agoThe answer being, per that post: author was worried about low quality randomness on Windows and ran it through a sha512 hash function which outputs fewer than 521 bits so the remaining ones will be left zero
- e79 2y agoUpdated link with corrected title: https://ericrafaloff.com/biased-nonce-generation-in-putty-for-nist-p-521-keys/ https://ericrafaloff.com/biased-nonce-generation-in-putty-fo...