Yes, but why would you want to? You shouldn't use RSA keys less than 1024 bits long anyway because of insufficient security.
On Wed, Apr 07, 2004 at 09:38:43PM -0700, David Brownell wrote: > Actually, I spent more time working with the library, and found that keys < > 361 bits are not able to sign messages. I found this value by generating a > key of N bits, and then attempting to sign a 1 byte message using that key. > All key sizes failed < 361. Is there a way I could have computed this value > programmatically rather than through trial and error? > > Thanks! > > -----Original Message----- > From: Wei Dai [mailto:[EMAIL PROTECTED] > Sent: Wednesday, April 07, 2004 8:09 PM > To: [EMAIL PROTECTED] > Subject: Re: Max Message Length When Signing? > > When you use RSASS, you should be able to sign arbitrarily long messages, as > long as the key size is sufficient to handle the hash size (which is fixed > for all message lengths). If, using the same key, you're able to sign short > messages but not long ones, then something is wrong. Please post sample code > if that's the case. > > On Wed, Apr 07, 2004 at 08:51:54AM -0700, David Brownell wrote: > > I am attempting to sign a message using the test application that > > ships with the Crypto++ library (which uses RSASS to sign a message). > > If I use a very small key to sign a very large file, I get a > > KeyTooSmall exception. I know that in the real world hashes of > > messages are signed rather than the messages themselves to alleviate > > this problem, but for the sake of argument, is there a way to tell at > > run time that maximum message size that can be signed for a given private > key? > > > > Thanks in advance for your help! > > David Brownell
