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seen Sep 18 at 17:28

Dec
13
awarded  Popular Question
May
8
revised What length should the padding be when encrypting or signing with RSA?
deleted 29 characters in body; edited title
May
5
accepted What length should the padding be when encrypting or signing with RSA?
May
5
comment What length should the padding be when encrypting or signing with RSA?
Oh.. and thank you very much for your answer!
May
5
comment What length should the padding be when encrypting or signing with RSA?
@JohnDeters I don't care if two identical messages yield the same output. I'm trying to implement a licensing system. (See my comments to fgrieu's answer and my other recent question on the site .) And I'm mainly concerned with signing.
May
5
comment What length should the padding be when encrypting or signing with RSA?
a) I should calculate a separate padding (is that the term instead of salt?) for each computer (in a random-like manner). And perhaps add a really-random part to it. b) The padding should be at least $256 + (2/3) n$ bits (which, if $n$ is 2048 - would leave me with a maximum of 426 bits (=53 bytes) for the computer-id (or its hash). Did I understand correctly?
May
5
comment What length should the padding be when encrypting or signing with RSA?
So... I understand from your answer that in the signature scheme where (as a licensing system) I'm signing a user's computer's hardware-id and returning it to the user's computer - having my application on that computer verify that the returned value is indeed the signed hardware-id: the following will be true:
May
3
comment What length should the padding be when encrypting or signing with RSA?
@fgrieu I'm converting a byte array to a BigInteger but first concatenating a new byte array to the end of the original one (before converting to BigInteger) and using that as $m$ in $m^d \bmod n$.
May
3
comment What length should the padding be when encrypting or signing with RSA?
@fgrieu concatenation. $(m+salt)^d \bmod n$ - Thanks. I was looking for that formatting.
May
3
comment What length should the padding be when encrypting or signing with RSA?
@fgrieu m^d mod n VS (m+salt)^d mod n
May
3
revised What length should the padding be when encrypting or signing with RSA?
deleted 23 characters in body; edited title
May
3
asked What length should the padding be when encrypting or signing with RSA?
Aug
10
comment What is the length of an RSA signature?
OK, I found the answer to that one here: stackoverflow.com/a/2922135/939213 - Yes, the modulus itself is 2048.
Aug
10
accepted What is the length of an RSA signature?
Aug
10
awarded  Commentator
Aug
10
comment What is the length of an RSA signature?
Thanks. And when we say 2048 bit encryption - Do we mean that N itself is 2048 bit?
Aug
10
comment What is the length of an RSA signature?
But since the signature is $m^d \bmod n$ - It seems that the length can even be $0$. Or are you referring to a system that will pad it as an extra feature?
Aug
10
asked What is the length of an RSA signature?
Apr
30
accepted How to sign a message using RSA?
Apr
30
comment How to sign a message using RSA?
Thanks. As for BigInteger - See this in .NET 4.0.