On Mon, Mar 13, 2006 at 01:34:54PM -0600, Allen Bierbaum wrote: > On 3/13/06, Vadym Fedyukovych <[EMAIL PROTECTED]> wrote: > > On Mon, Mar 13, 2006 at 10:34:05AM -0600, Allen Bierbaum wrote: > > ... > > > There are references on this list and elsewhere to key sizes around > > > 128-150 bits in length. > > > > Field element representation could be around 130-190 bit size. > > This is not exactly a signature or a public key. > > Maybe I should be more clear about what I need. > > What I want is to create a minimal data structure that could be used > on a remote node to initialize the cryptopp representation of the > public key. I do not need to use any formal representation that would > allow the key to be shared with other software. I just need a way to > represent the parameters that could be used by cryptopp to create the > same key on another machine. I can guarantee that the other node will > be running the same version of crypto and will be using the same field > parameters (??) namely ASN1::sect113r1(). > > >From what I understand of EC I think I probably just need a way to > share a curve point and possibly some other parameters.
Yes, just a point should be enough, with group parameters hard-coded into application. ... > > > What I am looking for is a way to represent the EC keys in the fewest > > > number of bits possible. My application knows that the bits represent > > > so there doesn't need to be any extra overhead that identify or > > > delimit the data. > > > > > > Can anyone point me to some code that will let me get a compact > > > representation of ec keys? > > > > Please consider to learn exactly what are you saving. > > ASN1/DER dump utility might be a way to go > > Where can I find this utility? There's dumpasn1 by Peter Gutmann available from http://www.cs.auckland.ac.nz/~pgut001/ and openssl command-line tool when used like openssl asn1dump -i -inform der -in yourfile Vadym Fedyukovych
