Example DANE's SPKI hash calculator

diff --git a/cmd/cer-dane-hash/main.go b/cmd/cer-dane-hash/main.go
new file mode 100644 (file)
index 0000000..5486a54
--- /dev/null
+++ b/cmd/cer-dane-hash/main.go
@@ -0,0 +1,47 @@
+// GoGOST -- Pure Go GOST cryptographic functions library
+// Copyright (C) 2015-2023 Sergey Matveev <stargrave@stargrave.org>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 of the License.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+// DANE's SPKI hash calculator
+package main
+
+import (
+       "crypto/sha256"
+       "crypto/x509"
+       "encoding/hex"
+       "encoding/pem"
+       "flag"
+       "fmt"
+       "io"
+       "log"
+       "os"
+)
+
+func main() {
+       flag.Parse()
+       data, err := io.ReadAll(os.Stdin)
+       if err != nil {
+               log.Fatalln(err)
+       }
+       b, _ := pem.Decode(data)
+       if b == nil || b.Type != "CERTIFICATE" {
+               log.Fatalln("no CERTIFICATE")
+       }
+       cer, err := x509.ParseCertificate(b.Bytes)
+       if err != nil {
+               log.Fatalln(err)
+       }
+       h := sha256.Sum256(cer.RawSubjectPublicKeyInfo)
+       fmt.Println(hex.EncodeToString(h[:]))
+}