first-commit

modules/util/keypair.go

@@ -0,0 +1,57 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/pem"
+)
+
+// GenerateKeyPair generates a public and private keypair
+func GenerateKeyPair(bits int) (string, string, error) {
+	priv, _ := rsa.GenerateKey(rand.Reader, bits)
+	privPem := pemBlockForPriv(priv)
+	pubPem, err := pemBlockForPub(&priv.PublicKey)
+	if err != nil {
+		return "", "", err
+	}
+	return privPem, pubPem, nil
+}
+
+func pemBlockForPriv(priv *rsa.PrivateKey) string {
+	privBytes := pem.EncodeToMemory(&pem.Block{
+		Type:  "RSA PRIVATE KEY",
+		Bytes: x509.MarshalPKCS1PrivateKey(priv),
+	})
+	return string(privBytes)
+}
+
+func pemBlockForPub(pub *rsa.PublicKey) (string, error) {
+	pubASN1, err := x509.MarshalPKIXPublicKey(pub)
+	if err != nil {
+		return "", err
+	}
+	pubBytes := pem.EncodeToMemory(&pem.Block{
+		Type:  "PUBLIC KEY",
+		Bytes: pubASN1,
+	})
+	return string(pubBytes), nil
+}
+
+// CreatePublicKeyFingerprint creates a fingerprint of the given key.
+// The fingerprint is the sha256 sum of the PKIX structure of the key.
+func CreatePublicKeyFingerprint(key crypto.PublicKey) ([]byte, error) {
+	bytes, err := x509.MarshalPKIXPublicKey(key)
+	if err != nil {
+		return nil, err
+	}
+
+	checksum := sha256.Sum256(bytes)
+
+	return checksum[:], nil
+}