adding documentation/analysis of key format

sshkeys/struct.go

@@ -1,11 +1,21 @@
 package sshkeys
 
-type SSHPubkey struct {
-	// Raw ???
-	B64 string
-	Comment string
+// EncryptedSSHKeyV1 represents an encrypted private key.
+type EncryptedSSHKeyV1 struct {
+	SSHKeyV1
+	Salt       string
+	Rounds     uint32
+	Passphrase string
 }
 
-type SSHPrivateKey struct {
-	
+// SSHKeyV1 represents an unencrypted private key.
+// We don't bother with the legacy (pre v1) keys. Sorry not sorry.
+// Patch your shit.
+type SSHKeyV1 struct {
+	CipherName string
+	KDFName    string
+	KDFOpts    string
+	NumKeys    uint32
+	Publickey  string
+	Privatekey string
 }