Timeline for How vulnerable is RSA when using it to encode ~1000s of datasets with 500bytes each? How easy can the private key passphrase be hacked?
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
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| Oct 29, 2013 at 9:24 | vote | accept | Larzan | ||
| Oct 21, 2013 at 17:27 | comment | added | Larzan | Yes, i was actually wondering how to do that (make it slower to guess). I found an PHP implementation of the PBKDF2 algorithm and will use this on the passphrase the user supplied, before using the result to decrypt the privateKey. After i am done i will present my final solution here. | |
| Oct 21, 2013 at 16:28 | comment | added | Ilmari Karonen | As for the second problem, what I meant is that is should be as slow as possible for an attacker to test whether a guessed password is correct. The typical way to do that is to use a deliberately slow function (such as PBKDF2) to transform the password into whatever it is that you'll actually use to verify the correctness of the password and to decrypt the encrypted RSA key (which can be the same thing -- if you use an authenticated key wrap algorithm like SIV to encrypt the RSA key, then a successful decryption means the password must be correct). | |
| Oct 21, 2013 at 16:23 | comment | added | Ilmari Karonen | IMO, "password strength checkers" frequently do more harm then good: diligent and security-conscious users don't need them, and lazy users will just pick the easiest password that passes the check, leading to passwords like "pa$$w0rd" or "asdfghjkl;'1234567890". Better to tell your users how to choose good passwords, and/or provide a secure random password generator. | |
| Oct 21, 2013 at 8:14 | comment | added | Larzan | Wouldn't it be better for the second problem to create a completely new key and send this to the user via snail mail? so that there is no relation between them? Or am i not getting sth here? I wanted the user to choose their pass for the backend (must be strong) and then (after login) have them insert another key that i send them via snail mail, which is the passphrase for the privatekey. | |
| Oct 21, 2013 at 7:43 | comment | added | Larzan | Thank you for this detailed and exhaustive answer, as i have to create the passphrase for the privatekey anyhow, i will now also change the user account password setting to only allow long and difficult passwords. As for the padding, i am adding random characters between the substrings to always reach the same final string length. The substrings are separated by three distinctive characters. The padding scheme that is used by RSA i have to check. | |
| Oct 21, 2013 at 7:34 | vote | accept | Larzan | ||
| Oct 29, 2013 at 9:24 | |||||
| Oct 21, 2013 at 7:34 | vote | accept | Larzan | ||
| Oct 21, 2013 at 7:34 | |||||
| Oct 20, 2013 at 19:06 | history | answered | Ilmari Karonen | CC BY-SA 3.0 |