I am using RSA 1024 bit keys for RSA signing with SHA-256. I had a question, I get a public key which is indeed 1024 bits in size but the private key is always not more than 2 digits. I use GenerateRandomWithKeySize with 1024 as the second argument to get the keys. What is the difference between using this and the rsa1024.dat file provided
Thanks On Oct 6, 4:00 pm, Cyptmon <[EMAIL PROTECTED]> wrote: > Thanks Jeff, I just wanted a back-of-the envelope calculation so just > wanted to confirm if what I was saying was correct > > Thanks once again for pointing me to the right sources > > On Oct 6, 3:27 pm, "Jeffrey Walton" <[EMAIL PROTECTED]> wrote: > > > Hi Cyptmon, > > > > 1. Compute hash over this data using SHA-512. This gives me a 512 bit > > > hash. > > > 2. Now I have the public key for the key pair that was used to > > > generated the signature. I do a signature verification using RSA-1024 > > ... > > > where should I get started ... > > > If using RSA with Appendix, > > seehttp://www.codeproject.com/useritems/RsaSignatureAppendix.asp. Instead > > of RSASS<PKCS1v15, SHA>, use RSASS<PKCS1v15, SHA512>. > > > If you are using RSA with Recovery, see the validat*.cpp included with > > Crypto++. PSSR is what you are intersted in. Since 32KB is large for a > > Recovery scheme, I would presume this is Appendix. > > > > = 32KB/81MB seconds + one RSA verification (0.07 ms) [The number given > > > is for one operation and I believe thats for 1Kb as you mentioned in > > > your earlier reply, so I can use this directly for 512 bits?) > > > You would probaby get the best results if you implemented the code and > > developed you're own benchmarks. You would probably have your numbers > > in less time it took to develop this email thread. > > > > and how much time will it take to do the simple > > > thing i just described > > > It is fairly trivial in Crypto++. It should take next to no time since > > Wei has provided the code in the validate and benchmark routines. > > > Jeff > > > On 10/6/07, Cyptmon <[EMAIL PROTECTED]> wrote: > > > > HI Tim > > > > Thanks for the reply > > > > I think I wasnt clear enough, so here is what I am going to do. I have > > > 32 KB of data which already has a signed hash (say Hash was generated > > > using SHA-512). Now what I want to do is verify this signature. So > > > this is what I will be doing > > > > 1. Compute hash over this data using SHA-512. This gives me a 512 bit > > > hash. > > > 2. Now I have the public key for the key pair that was used to > > > generated the signature. I do a signature verification using RSA-1024 > > > > So the total time I will calculate as : Time for Hashing 32KB + Time > > > for verifying it using the public key and hash > > > > = 32KB/81MB seconds + one RSA verification (0.07 ms) [The number given > > > is for one operation and I believe thats for 1Kb as you mentioned in > > > your earlier reply, so I can use this directly for 512 bits?) > > > > I think your earlier posts have made it clear, but I just want to be > > > sure if I am doing the right thing. > > > > Thanks for all the help > > > > One last thing, I would want to use crypto++ library to do the same, > > > where should I get started and how much time will it take to do the > > > simple thing i just described > > > > Thanks once again > > > > [ SNIP ] --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the "Crypto++ Users" Google Group. To unsubscribe, send an email to [EMAIL PROTECTED] More information about Crypto++ and this group is available at http://www.cryptopp.com. -~----------~----~----~----~------~----~------~--~---
