/
signer.go
50 lines (46 loc) · 1.15 KB
/
signer.go
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package signer
import (
"fmt"
"os"
"golang.org/x/crypto/openpgp"
)
// SignFile creates a detached ASCII-armoured signature for the given file.
func SignFile(filename, output, keyring, user, password string) error {
f, err := os.Open(keyring)
if err != nil {
return err
}
defer f.Close()
entities, err := openpgp.ReadArmoredKeyRing(f)
if err != nil {
return err
}
signer, err := findSigningEntity(entities, user)
if err != nil {
return err
}
if err := signer.PrivateKey.Decrypt([]byte(password)); err != nil {
return err
}
w, err := os.Create(output)
if err != nil {
return err
}
defer w.Close()
f2, err := os.Open(filename)
if err != nil {
return err
}
return openpgp.ArmoredDetachSign(w, signer, f2, nil)
}
// findSigningEntity finds the entity in a list with the given name.
func findSigningEntity(entities openpgp.EntityList, user string) (*openpgp.Entity, error) {
for _, entity := range entities {
for name, identity := range entity.Identities {
if name == user || identity.UserId.Name == user || identity.UserId.Email == user {
return entity, nil
}
}
}
return nil, fmt.Errorf("No entity found for the given user")
}