network profile
| bio | website | |
|---|---|---|
| location | Tel Aviv, Israel | |
| age | 35 | |
| visits | member for | 10 months |
| seen | Apr 4 at 8:59 | |
| stats | profile views | 4 |
Coding in Tel Aviv
|
May 11 |
awarded | Popular Question |
|
Aug 30 |
asked | Do I have to have a different salt for each password? |
|
Aug 30 |
comment |
How can I validate a hashed password if all I have is another hash? SRP has minimal back-and-forth: Just two messages to derive a shared key. There are two more messages if you want authentication. |
|
Aug 18 |
revised |
How do I store encrypted files on a web server and decrypt them locally? I updated the resolution to half the PBKDF2 width |
|
Aug 18 |
comment |
How do I store encrypted files on a web server and decrypt them locally? Wow, I was surprised! PBKDF2 is very expensive to widen! jsperf.com/1-pbkdf2-versus-many-decrypts I'll drop the key authentication and just use the keys for decryption. |
|
Aug 18 |
awarded | Editor |
|
Aug 18 |
revised |
How do I store encrypted files on a web server and decrypt them locally? Including a brief of my final resolution and offer for free code |
|
Aug 18 |
accepted | How do I store encrypted files on a web server and decrypt them locally? |
|
Aug 18 |
comment |
How do I store encrypted files on a web server and decrypt them locally? Regarding B, it depends which is more expensive to the user: Decrypting with a wrong key once per image (fast but many times) or doing the extra PBKDF2 (slow but just once). |
|
Aug 18 |
comment |
How do I calculate the maximum plain text length allowable for a certain cipher text length? Can VARCHAR(512) actually store 512 or does it need some sort of end-of-string marker? |
|
Aug 17 |
comment |
How do I store encrypted files on a web server and decrypt them locally? How come I need all the addition or modulo arithmetic? Couldn't I just use PBKDF2 to generate 512 bits, half which I would store in the index file for authentication, and the other half which I would use to decrypt the image's key? Per image I would store the first half of the 512 bits and the encryption of K_f. The advantage would be that I would only have to authenticate each password once, not once per file. The disadvantage: it would leak info about which files are encrypted with the same key. Other disadvantages? |
|
Aug 17 |
awarded | Scholar |
|
Aug 17 |
accepted | Can I use PBKDF2 for authentication and decryption? |
|
Aug 17 |
comment |
Can I use PBKDF2 for authentication and decryption? The point about halving the attacker's workload is convincing! |
|
Aug 17 |
awarded | Supporter |
|
Aug 16 |
awarded | Student |
|
Aug 16 |
comment |
How do I store encrypted files on a web server and decrypt them locally? I like the idea of being able to change the password without modifying all the images, though. That's pretty cool! |
|
Aug 16 |
comment |
How do I store encrypted files on a web server and decrypt them locally? Thanks for the detailed reply. I'm not having the client upload images nor encrypt them. Assume that those are done securely and uploaded securely to a server. I also want the access to the images to require just a plain browser and knowledge of the password so I have to live with the javascript hole. I don't even have user names: Anyone can download any file, but only people that know a password should be able to view and it should happen without fuss. |
|
Aug 16 |
asked | Can I use PBKDF2 for authentication and decryption? |
|
Aug 16 |
comment |
PBKDF2 and salt Would it be inappropriate to use PBKDF2 for both authentication and password stretching (assuming different salts)? |
