Hi Parch, > I do not understand the 'no such beast' reference at all, is that an > in joke to those who have read the book? Is it the to do list that > isn't? I suppose more formally, I'm not aware of such a primitive in the context of DSA. There are two types of Signature Schemes: one is appendage, the other such as RSA 'folds' the message into the signature. Hopefully others will be able to correct me and point you towards a DSA SS with Recovery.
> Finally, the 3rd link was not very obviously useful, as I can find no > example code for ECDSA itself in any of the links. General Protoype code for licensing schemes. If you can't use DSA, perhaps RSA could be helpful. Jeff On 6/12/07, Parch <[EMAIL PROTECTED]> wrote: > > Thank you for the answer on SHA. I was wondering how the compiler was > picking a default algorithm, and after you said to check the source, I > did again, and realised it was happening through a forward declare, > something I hadn't seen for template structs before: > > template <class EC, class H = SHA> > struct ECDSA; > > I do not understand the 'no such beast' reference at all, is that an > in joke to those who have read the book? Is it the to do list that > isn't? > > Finally, the 3rd link was not very obviously useful, as I can find no > example code for ECDSA itself in any of the links. > > thanks, > Parch > > > Correct, but it is not a Crypto++ limitation. > > Seehttp://groups.google.com/group/cryptopp-users/browse_thread/thread/36... > > > > > Firstly, I wonder if there is any special reasons for not > > > implementing it, or is it just on the to do list? > > > > Referring to Handbook of Applied Cryptography > > (http://www.cacr.math.uwaterloo.ca/hac/), there is no such beast. > > > > > But it seems like ECDSA is set up to do its own hashing by > > > default (is it using SHA?). > > > > If I recall, ECDSA use SHA1 (160 bits). See eccrypto.h and eccrypto.cpp. > > > > Perhaps the following may be of help for finding samples for use in your > > system:http://www.cryptopp.com/wiki/External_Samples > > > > Jeff > > > > On 6/12/07, Parch <[EMAIL PROTECTED]> wrote: > > > > > > > > > Hi, > > > I am new to using Crypto++, enjoying the puzzle of figuring out how it > > > all works. I have a couple questions about best use of ECDSA. > > > > > I am thinking of using the digital signatures with elliptic curves for > > > a product licensing scheme. I just tried to do ECDSA with message > > > recovery. Unfortunately, this doesn't seem to be implemented. Firstly, > > > I wonder if there is any special reasons for not implementing it, or > > > is it just on the to do list? Secondly, I wonder how to solve my real > > > problem. Let me explain what I was attempting: > > > > > When I wrote this code, I was considering transmitting recoverable > > > plaintext, but I was originally considering sending half of the > > > plaintext (the other half is read from the local machine, and must be > > > shared between parties prior to licensing), hashing the plaintext > > > parts together, and then using ECDSA to encrypt that hash to produce a > > > signature to send with the half plaintext. But it seems like ECDSA is > > > set up to do its own hashing by default (is it using SHA?). > > > > > Am I getting tangled up because I assumed I would be able to compare > > > plain-texts, with verification, where in fact I could be comparing > > > hashes, and using the ECDSA Signer/Verifier in a much simpler way? > > > > > And finally Wei Dai, this library is amazing. I would enjoy reading > > > general stuff about your education, how you learned to write amazing C+ > > > + code, why you designed Crypto++ this way, and so on. > > > > > thanks, > > > Parch > > > > > --~--~---------~--~----~------------~-------~--~----~ 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. -~----------~----~----~----~------~----~------~--~---
