4 ms·
> v2 addresses consist of the first 80 bits of the SHA-1 hash of the hidden services 1024 bit public RSA key. What is the danger of exposing the hash of the se
by brokenmachine 5y ago
> v2 addresses consist of the first 80 bits of the SHA-1 hash of the hidden services 1024 bit public RSA key.
What is the danger of exposing the hash of the services public key? Public keys are public anyway.
- laverya 5y agoIt's not the fact that the hash of the public key is exposed, it's the fact that 1. so little of the hash is exposed (only 80 bits of 160 for sha1), making it easier to find a collision 2. the hash is so weak (sha1 is widely considered broken), making it easier to find a collision 3. the underlying public key is so small, making it easier to derive the private key from the public key IIRC if you find a collision you can use that to take over / contest an onion address, and obviously reversing the public key into a private key gives you as much control over an onion address as the original creator.
- bawolff 5y agoFor 2) my understanding is that the security issues in sha1 are not relavent to finding preimages, which if im not mistaken is what you would need to take over an onion address. But maybe im mistaken.