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Dec
17
comment Can I store the initialisation vector (IV) in the filename?
If you lose your decryption software, and don't have any documentation to let you rebuild it, you're kind of SOL anyway.
Dec
17
comment How do we arrive to the equation for solving D in RSA?
Related: crypto.stackexchange.com/questions/5889/…
Dec
17
comment Factorizing N to derive D
Possible duplicate of Calculating RSA private exponent when given public exponent and the modulus factors using extended euclid (or possibly How do we arrive to the equation for solving D in RSA?)
Dec
17
comment What is the difference between RCCA and CCA2?
Relevant paper: eprint.iacr.org/2003/174.pdf
Dec
17
comment Combining a block cipher with a (pseudo) OTP
This scheme is not information-theoretically secure, thus losing the only advantage of OTP over conventional block/stream ciphers.
Dec
14
comment Hash functions vs Stream Ciphers in terms of Speed
Actually, as the person who asked the question you link to, I'm inclined to disagree with your premise that "We know that it's possible to create a hash using a stream cipher". As far as I can tell, none of the answers to the linked question actually present a construction that has been proven to turn a secure (i.e. indistinguishable for random) stream cipher into a secure (i.e. collision/preimage resistant) hash function.
Dec
14
comment Test vectors for PRESENT algorithm?
While the phrasing in the question may be a bit ambiguous, the way I interpret it is that the OP would like some other test vectors than these "usual" ones, for further testing.
Dec
14
comment How to apply linear cryptanalysis to PRESENT?
Ps. You might find this paper useful to skim, and maybe this as well.
Dec
14
comment How to apply linear cryptanalysis to PRESENT?
Your question seems quite broad to me, and you might want to narrow it down a bit. While I might be wrong, I don't think anyone's likely to post a complete walkthrough of cryptanalysing PRESENT here, and in any case, it might not even fit in our answer length limit. However, if you could tell us how much you've figured out on your own, and where specifically you're getting stuck, that might increase your chance of getting useful answers.
Dec
14
comment Is symmetric encryption vulnerable to plain-text-attacks?
@David天宇Wong: That's basically what adding a message authentication layer does: it makes the probability of a successful decryption oracle query (on a message not previously obtained from the encryption oracle) negligible, and thus effectively makes the CCA game identical to the CPA game.
Dec
13
comment What are the negative consequences for choosing 8 S-boxes for DES vs 1 S-box for AES?
I'd guess mostly implementation complexity.
Nov
26
comment How to check if a function is significant or not?
@user3193259: How did you "see" that it's not reaching zero? Just by plotting? That can be quite misleading for slowly converging functions. Instead, you might want to try solving the equation $x = 1/(\log n)^{1/2}$ for $n$ as a function of $x$.
Nov
26
comment Why is PuTTYgen-created RSA public exponent(e) not in {3,17,65537}?
According to The Jargon File, 37 is the most common answer when people are asked to pick a random number from 1 to 100. No citation, though. :(
Nov
26
comment Decoding base64 encoded message with a key
Note that many programming languages / environments include a built-in tool for such character replacement, e.g. tr/// for Perl, strtr() for PHP, string.translate() for Python, etc. Many of these are modeled on the Unix command-line tool tr. In particular, to decode your example string using Unix tools, just run the command echo ucaUCo4NmA88Tws8BoQsKAXdBcDn | tr 'gP9jOzA75VyIW6FRuHZimQcLB1rCTKpGN8hdEXw0eY3kMx+/JDUntsob4a2qfSv' 'A-Za-z0-9+' | base64 -d.
Nov
21
comment For AES CBC, can I encrypt the IV with AES ECB and the same key and include it with the message?
Related: Why is the IV passed in the clear when it can be easily encrypted?
Nov
14
comment Does complicating a flawed algorithm make it secure?
Related: What is the actual difference between security through obscurity and true encryption? and Why should I make my cipher public?
Nov
5
comment Is it possible to correct the exponent of an RSA public key if it has been altered?
@aadithvmenon: No, that wouldn't really be on topic here. In any case, you're presumably meant to solve the puzzle yourself. You could maybe ask for hints in chat, but you need a few more rep points to get full access to it. (And of course, there's still no guarantee that anyone will actually feel like taking the time to help you.)
Nov
5
comment Is it possible to correct the exponent of an RSA public key if it has been altered?
If you've only got the public key and the message, then you won't be able to decrypt anyway, regardless of whether you correct the exponent or not. Unless, of course, "taken wrongly" means that the person who encrypted it did something silly like encrypt with the decryption exponent, in which case... well, it should be obvious what to do. :-)
Nov
5
comment Is it possible to correct the exponent of an RSA public key if it has been altered?
"Just a text file" doesn't really tell much; a lot of the formats for storing RSA keys are text files (often containing a bunch of base64-encoded data). If it starts with a line like ---- BEGIN (whatever) ----, Google for that line to see what type of key file it is. If it starts with something like <RSAKeyValue> and has lots of angle brackets in general, it's probably in XKMS format. If it's just got two numbers (a large and a small one), well those are probably the modulus and the exponent.
Nov
4
comment Is it possible to correct the exponent of an RSA public key if it has been altered?
That depends on the key file format you're using.