Rename convert pubkey folder

tools/convert-pem-pubkey/main.go

@@ -0,0 +1,81 @@
+// Copyright (C) 2022 Paderborn Center for Parallel Computing, Paderborn University
+// This code is released under MIT License:
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// 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 OR COPYRIGHT HOLDERS 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.
+package main
+
+import (
+	"crypto/ed25519"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/pem"
+	"fmt"
+	"os"
+)
+
+func main() {
+	filepath := ""
+	if len(os.Args) > 1 {
+		filepath = os.Args[1]
+	} else {
+		PrintUsage()
+		os.Exit(1)
+	}
+
+	pubkey, err := LoadEd255519PubkeyFromPEMFile(filepath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error: %s\n", err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Fprintf(os.Stdout,
+		"CROSS_LOGIN_JWT_PUBLIC_KEY=%#v\n",
+		base64.StdEncoding.EncodeToString(pubkey))
+}
+
+// Loads an ed25519 public key stored in a file in PEM format
+func LoadEd255519PubkeyFromPEMFile(filePath string) (ed25519.PublicKey, error) {
+	buffer, err := os.ReadFile(filePath)
+	if err != nil {
+		return nil, err
+	}
+
+	block, _ := pem.Decode(buffer)
+	if block == nil {
+		return nil, fmt.Errorf("no pem block found")
+	}
+
+	pubkey, err := x509.ParsePKIXPublicKey(block.Bytes)
+	if err != nil {
+		return nil, err
+	}
+
+	ed25519PublicKey, success := pubkey.(ed25519.PublicKey)
+	if !success {
+		return nil, fmt.Errorf("not an ed25519 key")
+	}
+
+	return ed25519PublicKey, nil
+}
+
+func PrintUsage() {
+	fmt.Fprintf(os.Stderr, "Usage: %s <filename>\n", os.Args[0])
+	fmt.Fprintf(os.Stderr, "where <filename> contains an Ed25519 public key in PEM format\n")
+	fmt.Fprintf(os.Stderr, "(starting with '-----BEGIN PUBLIC KEY-----')\n")
+}