1// Copyright 2016 The go-ethereum Authors
2// This file is part of the go-ethereum library.
3//
4// The go-ethereum library is free software: you can redistribute it and/or modify
5// it under the terms of the GNU Lesser General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8//
9// The go-ethereum library is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12// GNU Lesser General Public License for more details.
13//
14// You should have received a copy of the GNU Lesser General Public License
15// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
16
17// signFile reads the contents of an input file and signs it (in armored format)
18// with the key provided, placing the signature into the output file.
19
20package build
21
22import (
23	"bytes"
24	"fmt"
25	"os"
26
27	"golang.org/x/crypto/openpgp"
28)
29
30// PGPSignFile parses a PGP private key from the specified string and creates a
31// signature file into the output parameter of the input file.
32//
33// Note, this method assumes a single key will be container in the pgpkey arg,
34// furthermore that it is in armored format.
35func PGPSignFile(input string, output string, pgpkey string) error {
36	// Parse the keyring and make sure we only have a single private key in it
37	keys, err := openpgp.ReadArmoredKeyRing(bytes.NewBufferString(pgpkey))
38	if err != nil {
39		return err
40	}
41	if len(keys) != 1 {
42		return fmt.Errorf("key count mismatch: have %d, want %d", len(keys), 1)
43	}
44	// Create the input and output streams for signing
45	in, err := os.Open(input)
46	if err != nil {
47		return err
48	}
49	defer in.Close()
50
51	out, err := os.Create(output)
52	if err != nil {
53		return err
54	}
55	defer out.Close()
56
57	// Generate the signature and return
58	return openpgp.ArmoredDetachSign(out, keys[0], in, nil)
59}
60
61// PGPKeyID parses an armored key and returns the key ID.
62func PGPKeyID(pgpkey string) (string, error) {
63	keys, err := openpgp.ReadArmoredKeyRing(bytes.NewBufferString(pgpkey))
64	if err != nil {
65		return "", err
66	}
67	if len(keys) != 1 {
68		return "", fmt.Errorf("key count mismatch: have %d, want %d", len(keys), 1)
69	}
70	return keys[0].PrimaryKey.KeyIdString(), nil
71}
72