From a30d6403f723765b8f9b7609e7eb3ade0f5434a0 Mon Sep 17 00:00:00 2001
From: Niall Sheridan <nsheridan@gmail.com>
Date: Sat, 10 Sep 2016 17:40:23 +0100
Subject: Make client a top-level package for consistency

---
 client/keys.go | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 client/keys.go

(limited to 'client/keys.go')

diff --git a/client/keys.go b/client/keys.go
new file mode 100644
index 0000000..4b3b69e
--- /dev/null
+++ b/client/keys.go
@@ -0,0 +1,84 @@
+package client
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	"fmt"
+
+	"golang.org/x/crypto/ed25519"
+	"golang.org/x/crypto/ssh"
+)
+
+// Key is a private key.
+type Key interface{}
+type keyfunc func(int) (Key, ssh.PublicKey, error)
+
+var (
+	keytypes = map[string]keyfunc{
+		"rsa":     generateRSAKey,
+		"ecdsa":   generateECDSAKey,
+		"ed25519": generateED25519Key,
+	}
+)
+
+func generateED25519Key(bits int) (Key, ssh.PublicKey, error) {
+	p, k, err := ed25519.GenerateKey(rand.Reader)
+	if err != nil {
+		return nil, nil, err
+	}
+	pub, err := ssh.NewPublicKey(p)
+	if err != nil {
+		return nil, nil, err
+	}
+	return &k, pub, nil
+}
+
+func generateRSAKey(bits int) (Key, ssh.PublicKey, error) {
+	k, err := rsa.GenerateKey(rand.Reader, bits)
+	if err != nil {
+		return nil, nil, err
+	}
+	pub, err := ssh.NewPublicKey(&k.PublicKey)
+	if err != nil {
+		return nil, nil, err
+	}
+	return k, pub, nil
+}
+
+func generateECDSAKey(bits int) (Key, ssh.PublicKey, error) {
+	var curve elliptic.Curve
+	switch bits {
+	case 256:
+		curve = elliptic.P256()
+	case 384:
+		curve = elliptic.P384()
+	case 521:
+		curve = elliptic.P521()
+	default:
+		return nil, nil, fmt.Errorf("Unsupported key size. Valid sizes are '256', '384', '521'")
+	}
+	k, err := ecdsa.GenerateKey(curve, rand.Reader)
+	if err != nil {
+		return nil, nil, err
+	}
+	pub, err := ssh.NewPublicKey(&k.PublicKey)
+	if err != nil {
+		return nil, nil, err
+	}
+	return k, pub, nil
+}
+
+// GenerateKey generates a ssh key-pair according to the type and size specified.
+func GenerateKey(keytype string, bits int) (Key, ssh.PublicKey, error) {
+	f, ok := keytypes[keytype]
+	if !ok {
+		var valid []string
+		for k := range keytypes {
+			valid = append(valid, k)
+		}
+		return nil, nil, fmt.Errorf("Unsupported key type %s. Valid choices are %s", keytype, valid)
+	}
+	return f(bits)
+}
-- 
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