Serialize and deserialize ecdsa, dsa, rsa keys

[Daniel Huckstep]

Is there a simple/standard way to serialize/deserialize these keys, or do you have to roll your own?

There is the encoding/pem package, but it wants a byte slice, so even then I'd have to do some shenanigans to turn any one of those keys into a byte slice. Then of course you need to go the other way. In the case of ecdsa, you really just have the 3 big.Int values, since the curve you just grab from the package. In dsa, you have 5 big.Int values in total, and with rsa, 3 big.Int values and the Primes slice.

Am I just missing something? `ssh-keygen -t dsa` gives me a nice looking output in my ~/.ssh folder, which seems like it should be my target, but it's just base64 encoded "stuff" and I don't know what that stuff is supposed to be.

- Daniel

[Daniel Huckstep]

Oh look there's a DSA manpage... From here I can see asn1/pem will get me dealing with DSA keys.

- Daniel

[Jonathan Pittman]

You can also take a look at the files in go.crypto/ssh.

http://go.pkgdoc.org/code.google.com/p/go.crypto/ssh

http://code.google.com/p/go/source/browse/ssh/keys.go?repo=crypto

http://code.google.com/p/go/source/browse/ssh/server.go?repo=crypto#60

The basic of it is that you need to decode the base64 encoded form into a []byte using something like base64.StdEncoding.Decode or base64.StdEncoding.DecodeString.  Then the resulting bytes are more easily picked apart into their respective pieces of the key.  The encoding/pem package parses the header and footer and does the base64 encode/decode (for private keys) for you in the respective functions.  So, that is definitely a good starting point.