/
sign.go
69 lines (58 loc) · 1.39 KB
/
sign.go
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package main
import (
"crypto"
"crypto/sha256"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"io/ioutil"
"fmt"
"encoding/base64"
)
func writeFile(kalimat, sig string){
d1 := []byte(kalimat)
err := ioutil.WriteFile("msg.txt", d1, 0644)
if (err != nil){
panic(err)
}
d2 := []byte(sig)
err = ioutil.WriteFile("sig.txt", d2, 0644)
if (err != nil){
panic(err)
}
}
func main(){
var kalimat string = "Cyber Academy Luar Biasa"
priv, err := ioutil.ReadFile("private.key")
if err != nil {
panic(err)
}
privPem, _ := pem.Decode(priv)
var privPemBytes []byte
privPemBytes, err = x509.DecryptPEMBlock(privPem, []byte("1234"))
if err != nil {
panic(err)
}
var parsedKey interface{}
if parsedKey, err = x509.ParsePKCS1PrivateKey(privPemBytes); err != nil {
fmt.Println(err)
if parsedKey, err = x509.ParsePKCS8PrivateKey(privPemBytes); err != nil {
fmt.Println(err)
}
}
var privateKey *rsa.PrivateKey
var ok bool
privateKey, ok = parsedKey.(*rsa.PrivateKey)
if !ok {
panic("Something wrong, cannot continue")
}
// Signing
sum := sha256.Sum256([]byte(kalimat))
signature, err := rsa.SignPKCS1v15(rand.Reader, privateKey, crypto.SHA256, sum[:])
if (err != nil){
panic(err)
}
sEnc := base64.StdEncoding.EncodeToString([]byte(signature))
writeFile(kalimat, sEnc)
}