// DecryptDecryptInfo is used to extract a decryptInfo object by attempting decryption
// with a given recipientKey. This must be attempted for each decryptInfo in the header
// until one works or none work, as miniLock deliberately provides no indication of
// intended recipients.
func DecryptDecryptInfo(diEnc, nonce []byte, ephemPubkey, recipientKey *taber.Keys) (*DecryptInfoEntry, error) {
plain, err := recipientKey.Decrypt(diEnc, nonce, ephemPubkey)
if err != nil {
return nil, ErrCannotDecrypt
}
di := new(DecryptInfoEntry)
err = json.Unmarshal(plain, di)
if err != nil {
return nil, err
}
return di, nil
}
// ExtractFileInfo pulls out the fileInfo object from the decryptInfo object,
// authenticating encryption from the sender.
func (di *DecryptInfoEntry) ExtractFileInfo(nonce []byte, recipientKey *taber.Keys) (*FileInfo, error) {
// Return on failure: minilockutils.DecryptionError
senderPubkey, err := di.SenderPubkey()
if err != nil {
return nil, err
}
plain, err := recipientKey.Decrypt(di.FileInfoEnc, nonce, senderPubkey)
if err != nil {
return nil, ErrCannotDecrypt
}
fi := new(FileInfo)
err = json.Unmarshal(plain, fi)
if err != nil {
return nil, err
}
return fi, nil
}