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May
22
awarded  Cleanup
May
22
revised Hill-cipher, disordered alphabet
rolled back to a previous revision
May
22
comment How random are commercial TRNGS
I think the question, as stated, is a perfectly fine question. It's not asking for product recommendations; it is asking about how one can evaluate a range of products out there. Seems like a great question to me! (The follow-on questions in the comments about specific products, however, are not good questions: they do not belong on this site. Search for "shopping question" to learn more about why not.)
May
22
answered Perfect Secrecy, two Definitions
May
22
comment How much data can I encrypt with AES before I need to change the key in CBC mode?
@makerofthings7, to understand what it means, start by understanding what 'advantage' means at a deep level. At a very rough, crude level, you can think of it as representing the probability that an attacker learns some information about the message. (However, strictly speaking, this is a simplification.) In this case, we are saying roughly "If you encrypt no more than $2^{48}$ blocks of data under the same key, the probability that the attacker learns some information about the message is at most $1/2^{32}$". Roughly.
May
22
answered Do I need to keep a 64-bit version number secret?
May
22
answered How much data can I encrypt with AES before I need to change the key in CBC mode?
May
20
comment Is this a sensible cryptographic protocol intending to reduce the impact of compromised security?
@MattFellows, well, here's one scenario that comes to mind: what if they breach one of those systems first, then use it as a jumping-off point to attack your server? P.S. If the server is only intended to be accessed by limited IP addresses, it might be worthwhile to set up a firewall (or TCP wrappers policy) to actively block connection attempts from any other IP address.
May
20
comment Are there any hand ciphers not obsoleted by computer cryptanalysis?
Thanks, @PaĆ­loEbermann. Yes, I'm aware of it. (For reasons that probably aren't relevant to anyone else, it doesn't work for me: on my primary platform, something on my browser's configuration makes the "close" link not work. Maybe an ad blocker or something, I've never taken the time to fully trouble shoot it. My apologies for cluttering things up with comments as a result.)
May
19
comment Recommended way of adding a pepper/secret key to password before hashing?
@TheDisintegrator, the pepper should be truly random (e.g., generated from /dev/urandom and kept secret thereafter). I don't know about what order your $hash_h mac$ accepts parameters in; I explain where the inputs should go in my answer. As far as how to call bcrypt, that will depend upon your particular language and library's API. If you want to know how to code this up, that's better for StackOverflow. You choose the work factor for bcrypt so that computing bcrypt takes, say, 50ms.
May
19
comment Are there any hand ciphers not obsoleted by computer cryptanalysis?
Duplicate of crypto.stackexchange.com/q/1653/351 (see also crypto.stackexchange.com/q/844/351).
May
19
answered Why this k parameter is in unary in adversary PPT algorithm?
May
18
comment When truncating an AES MAC value by “w” , how do I justify that “w” is still negligible?
@Maeher, I have a different take. I think it's a perfectly reasonable use of the term. Outside of complexity theory, the standard engineering meaning of the term "negligible" is "so small it can be safely ignored/safely treated as zero". That seems to apply fine here.
May
18
comment Alternatives to HMAC + CBC?
It doesn't matter whether you separate out the signature into a separate column or not.
May
18
revised Alternatives to HMAC + CBC?
added 485 characters in body
May
18
answered Alternatives to HMAC + CBC?
May
17
comment Is this a sensible cryptographic protocol intending to reduce the impact of compromised security?
"The assumption that the compromise wouldn't be permanent is made due to monitoring of all network traffic." - That makes no sense. It is not accurate or prudent to assume that monitoring of network traffic will detect all, or even most, of all compromises (or of instances of exfiltration of data by an attacker). I'm afraid your confidence in ability to detect compromises is sorely misplaced. Just look at some of the APT threats that have managed to penetrate systems and avoid detection for years.
May
17
revised Hill-cipher, disordered alphabet
added 1827 characters in body
May
16
revised Hill-cipher, disordered alphabet
added 1827 characters in body
May
16
answered Hill-cipher, disordered alphabet