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package guestagent
import (
"bytes"
"fmt"
"io"
"strings"
"filippo.io/age"
"filippo.io/age/armor"
)
const maxPlaintext = 1 << 16
func seal(recipient *age.X25519Recipient, plaintext []byte) (string, error) {
var out bytes.Buffer
armored := armor.NewWriter(&out)
w, err := age.Encrypt(armored, recipient)
if err != nil {
return "", err
}
if _, err := w.Write(plaintext); err != nil {
return "", err
}
if err := w.Close(); err != nil {
return "", err
}
if err := armored.Close(); err != nil {
return "", err
}
return out.String(), nil
}
func open(identity *age.X25519Identity, ciphertext string) ([]byte, error) {
r, err := age.Decrypt(armor.NewReader(strings.NewReader(ciphertext)), identity)
if err != nil {
return nil, err
}
plaintext, err := io.ReadAll(io.LimitReader(r, maxPlaintext+1))
if err != nil {
return nil, err
}
if len(plaintext) > maxPlaintext {
return nil, fmt.Errorf("guestagent: the sealed body is larger than %d bytes", maxPlaintext)
}
return plaintext, nil
}
