xtrcode / kex

kex | ECDH Key Exchange in Go

kex | ECDH Key Exchange in Go

kex is a small wrapper around go's crypto/elliptic library I used in a personal project to further abstract and simplify shared secret generation within an client/server configuration.

INSTALL

go get github.com/xtrcode/kex

USAGE

    
alice := kex.NewP512()
bob := kex.NewP512()

alicePK, err := alice.Encode()
if err != nil {
    log.Fatal("Encoding alice' public key failed")
}

bobPK, err := bob.Encode()
if err != nil {
    log.Fatal("Encoding bobs public key failed")
}

// transmit data beep bloop

if err = bob.Decode(alicePK); err != nil {
    log.Fatal(err)
}

if err = alice.Decode(bobPK); err != nil {
    log.Fatal(err)
}

alice.Calculate()
bob.Calculate()

fmt.Printf("\nShared key (Alice) %x\n", alice.Sum224())
fmt.Printf("\nShared key (Bob)  %x\n", bob.Sum224())

The generated byte-sequence of kexObj.Encode() is encoded with encoding/gob and ready for transmission. At the other end just throw the byte-sequence into kexObj2.Decode(data), calculate your shared secret and start communicating!

For an (non)official implementation see: https://github.com/golang/crypto/blob /e8f229864d71a49e5fdc4a9a134c5f85c4c33d64/ssh/kex.go#L210-L377

FAQ

Q: Why ECDH and not DHE?
A: Go doesn't support DHE out-of-the box (at least to my knowledge).

Q: Why don't you check the factors?
A: Kex isn't intended for production use. Please create a pull request if you
   want to contribute additional features.

LICENSE

This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a compiled binary, for any purpose, commercial or non-commercial, and by any means.

In jurisdictions that recognize copyright laws, the author or authors of this software dedicate any and all copyright interest in the software to the public domain. We make this dedication for the benefit of the public at large and to the detriment of our heirs and successors. We intend this dedication to be an overt act of relinquishment in perpetuity of all present and future rights to this software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to http://unlicense.org/

kex's Issues

return errors, remove logging

To gain full control over error management you should really return any encountered errors instead of ignoring or logging them.

kex, err := NewKex(...)
if err != nil {
    // whatever
}
// use kex

We can now also ensure that kex is never nil without explicitly checking it.