Another GPG encryption/decryption sign/verify script on gist

Generate keypairs

gpg --full-generate-key

# use any email, i used [email protected], passphrase=123456

$ gpg --output public.pgp --armor --export [email protected]
$ gpg --output private.pgp --armor --export-secret-key  [email protected]

$  gpg --list-keys
$HOME/.gnupg/pubring.kbx
--------------------------------
pub   rsa2048 2023-05-11 [SC]
      52FCDCD73A663460A86839AF49A3059CC639E767
uid           [ultimate] user1 <[email protected]>
sub   rsa2048 2023-05-11 [E]

$ gpg --list-secret-keys
$HOME/.gnupg/pubring.kbx
--------------------------------
sec   rsa2048 2023-05-11 [SC]
      52FCDCD73A663460A86839AF49A3059CC639E767
uid           [ultimate] user1 <[email protected]>
ssb   rsa2048 2023-05-11 [E]

main.go

package main

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"strings"

	"os"

	"golang.org/x/crypto/openpgp"
	"golang.org/x/crypto/openpgp/armor"
	"golang.org/x/crypto/openpgp/packet"
)

const (
	publicKeyring = "public.pgp"
	secretKeyring = "private.pgp"
	secretString  = "foooo"
	passphrase    = "123456"
)

var ()

func main() {

	f, err := os.Open(publicKeyring)
	if err != nil {
		panic(err)
	}
	defer f.Close()
	block, err := armor.Decode(f)
	if err != nil {
		panic(err)
	}

	entity, err := openpgp.ReadEntity(packet.NewReader(block.Body))
	if err != nil {
		panic(err)
	}

	keyringFileBuffer, err := os.Open(secretKeyring)
	if err != nil {
		panic(err)
	}
	defer keyringFileBuffer.Close()
	keyRing, err := openpgp.ReadArmoredKeyRing(keyringFileBuffer)
	if err != nil {
		panic(err)
	}

	for _, k := range keyRing {
		fmt.Printf("KeyIDs found in keyring: %d\n", k.PrimaryKey.KeyId)
	}

	passphraseByte := []byte(passphrase)
	fmt.Println("Decrypting private key using passphrase")
	for _, subkey := range keyRing[0].Subkeys {
		err = subkey.PrivateKey.Decrypt(passphraseByte)
		if err != nil {
			panic(err)
		}
	}

	// Encrypt/Decrypt

	buf := new(bytes.Buffer)
	msg, err := armor.Encode(buf, "PGP MESSAGE", nil)
	if err != nil {
		panic(err)
	}
	w, err := openpgp.Encrypt(msg, []*openpgp.Entity{entity}, nil, &openpgp.FileHints{IsBinary: false}, nil)
	if err != nil {
		panic(err)
	}
	_, err = w.Write([]byte(secretString))
	if err != nil {
		panic(err)
	}
	err = w.Close()
	if err != nil {
		panic(err)
	}
	err = msg.Close()
	if err != nil {
		panic(err)
	}

	bc, err := ioutil.ReadAll(buf)
	if err != nil {
		panic(err)
	}
	//encStr := base64.StdEncoding.EncodeToString(bc)

	fmt.Printf("Encrypted Secret: \n%s\n", bc)

	//*****************************

	block, err = armor.Decode(bytes.NewBuffer(bc))
	if err != nil {
		panic(err)
	}

	md, err := openpgp.ReadMessage(block.Body, keyRing, nil, nil)
	if err != nil {
		panic(err)
	}
	bb, err := ioutil.ReadAll(md.UnverifiedBody)
	if err != nil {
		panic(err)
	}
	decStr := string(bb)
	fmt.Printf("decrypted: %s\n", decStr)

	// SIGN/VERIFY

	message := bytes.NewBufferString(secretString)

	var signingEntity *openpgp.Entity
	for _, subkey := range keyRing {
		err = subkey.PrivateKey.Decrypt(passphraseByte)
		if err != nil {
			panic(err)
		}
		signingEntity = subkey
	}

	out := new(bytes.Buffer)
	err = openpgp.ArmoredDetachSign(out, signingEntity, message, nil)
	if err != nil {
		panic(err)
	}
	sig := out.Bytes()
	fmt.Printf("Signed:  \n%s\n", sig)

	pkeyRing := openpgp.EntityList{}
	pkeyRing = append(pkeyRing, entity)

	myReader := strings.NewReader(secretString)
	ee, err := openpgp.CheckArmoredDetachedSignature(pkeyRing, myReader, bytes.NewReader(sig))
	if err != nil {
		panic(err)
	}
	for _, s := range ee.Identities {
		fmt.Printf("Signature Verified: \n%s\n", s.Name)
	}

}

public.pgp

private.pgp

$ go run main.go 

KeyIDs found in keyring: 5306090956871296871
Decrypting private key using passphrase
Encrypted Secret: 
-----BEGIN PGP MESSAGE-----

wcBMA8pAO4LQ+CtyAQgAexlPQKSB1sx+HC5ZegDL4Z/Jb2wu4kVE6a96BKEEaXky
XS4+ycVVxW4MU1/e6pw4BQSg/ZOqDk89ePIuasXm7UDA3Op4VWYScXHALnYXDnQZ
37cdW26ehkYJgNUVpi01O+UVKEV+p5mNn6xOjRYbTSSvHA5AWD9bC16TjWyFS//w
+r4LXhHEH9E1sHfD1pZgYkdKLcZZ4Voo7Pay282Zrp92rFGvrMGYh6FHrF3ZfcWo
sfA4Ifg+OtgDAdJePa37j1nnUo4UabyRbjl10ERUFeU17Bd5sBejxvAfD3wy/RJi
WmvC+j/PMgWCWp+x5VtX940CQlZ97HmTn2n2ww8xQtLgAeQHHfXkW31tv8NN353e
60s84dQA4F7gmOF+cOBr4geQ95fgluJSaw2c4CLgbeCc5PHtLb3a6FKQnxuI2jsa
cS/iTOxKtuFidgA=
=OXqU
-----END PGP MESSAGE-----
decrypted: foooo
Signed:  
-----BEGIN PGP SIGNATURE-----

wsBcBAABCAAQBQJkXOsjCRBJowWcxjnnZwAAzWYIANISDHilfOVXW60yKU0bjbD8
DuL455IGJjBnsA1yx7jQM0Yj8alYk20aiDMk+S4WUfG9WKcGYDWFQdZGp0YiMl8B
WMzUbrwoVhazRd/6lvOJ4r1lbqBSUGXs9GtuvEUW8vjOr/6LzecBLBV8EXivT2Xz
eT4S3UV68O57zkKpUqGGzp5oT+4JjtMTODuNczz59i+Rk174Eiy1EqQBbEYrIC3e
4W7xjWu+fdq5d2Xz/iuJJRy6O7VI/l/uK/rU3eScqE/YTHbhgdwzUnRCRczFQ2cI
UOi/u/pm6VvE+8FbIYprhibDESh6BNAtcvrZ2g45p2+XwPjsk6kQe8Ar/IcqBhU=
=uYRp
-----END PGP SIGNATURE-----
Signature Verified: 
user1 <[email protected]>

salrashid123/gpg_golang.md