But, if I initialize the struct to zero with memset, Is it work correctly? On 9 dic, 13:04, Rafael Vargas <[email protected]> wrote: > Just keep in mind that you'll be signing the padding bytes also. > > And if your structure contains any byte with value zero, your struct > will be just half signed. > > -- > Vargas > > On Wed, Dec 9, 2009 at 08:33, Charlie <[email protected]> wrote: > > Thanks everybody!! > > > I've tried something thats it's very easy. I've type the following > > code: > > > struct c c1; > > //... > > //I fill the strct c1... > > //... > > char info[sizeof(c1)]; > > memcpy (info, &c1, sizeof(c1)); > > string info_msg = c1; > > > And now, I sign the string info_msg and verify the signature and > > everything works fine! > > > Thanks for your ideas! > > > On 9 dic, 05:23, Geoff Beier <[email protected]> wrote: > >> On Mon, Dec 7, 2009 at 06:35, Charlie <[email protected]> wrote: > >> > Hi! > > >> > I know how to sign a string with crypto++, but, how can I sign a C > >> > struct, for example, the next struct? > > >> > struct c > >> > { > >> > double x; > >> > double y; > >> > int z; > >> > }; > > >> You need to serialize your structure first, then sign/verify your > >> serialized representation. There are a few common ways to do this. Two > >> good ones are boost::serialziation and ASN1. Whichever way you do it, > >> once you settle on a serialization format, it's just a matter of > >> signing the bytes that are emitted by your serializer and verifying > >> the bytes before you feed them to your deserializer. > > >> If you just use the in-memory representation of your native struct, it > >> won't be portable across compilers/runtimes/platforms, as others have > >> noted. > > >> FWIW, the most common standards that need to do this use ASN.1 to > >> specify the structure and the Distinguished Encoding Rules (DER) to > >> encode/decode it. > > >> There's a very good commercial ASN.1 compiler/library > >> here:http://www.obj-sys.com/products_asn1c.shtml > > >> You can get free ASN.1 compilers/libraries > >> here:http://code.google.com/p/a2c/http://lionet.info/asn1c/ > > >> Boost serialization + documentation live > >> here:http://www.boost.org/doc/libs/1_41_0/libs/serialization/doc/index.html > > >> You could naturally roll your own, also. The main thing is that the > >> serialized representation needs to be the same across all the versions > >> of the compilers/runtimes you care about. Unless your project is > >> really trivial, I'd go with one of the above. If you only need to > >> interoperate with different versions of your own code (albeit possibly > >> across different platforms/versions of your compiler/runtime) I'd use > >> boost. It's certainly easiest. If you need to interoperate with > >> multiple independent implementations of your format, ASN1 is worth the > >> learning curve IMO. > > >> HTH, > > >> Geoff > > > -- > > 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 > > athttp://www.cryptopp.com. > >
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