github.com/sberex/go-sberex@v1.8.2-0.20181113200658-ed96ac38f7d7/internal/build/pgp.go (about)

     1  // This file is part of the go-sberex library. The go-sberex library is 
     2  // free software: you can redistribute it and/or modify it under the terms 
     3  // of the GNU Lesser General Public License as published by the Free 
     4  // Software Foundation, either version 3 of the License, or (at your option)
     5  // any later version.
     6  //
     7  // The go-sberex library is distributed in the hope that it will be useful, 
     8  // but WITHOUT ANY WARRANTY; without even the implied warranty of
     9  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser 
    10  // General Public License <http://www.gnu.org/licenses/> for more details.
    11  
    12  // signFile reads the contents of an input file and signs it (in armored format)
    13  // with the key provided, placing the signature into the output file.
    14  
    15  package build
    16  
    17  import (
    18  	"bytes"
    19  	"fmt"
    20  	"os"
    21  
    22  	"golang.org/x/crypto/openpgp"
    23  )
    24  
    25  // PGPSignFile parses a PGP private key from the specified string and creates a
    26  // signature file into the output parameter of the input file.
    27  //
    28  // Note, this method assumes a single key will be container in the pgpkey arg,
    29  // furthermore that it is in armored format.
    30  func PGPSignFile(input string, output string, pgpkey string) error {
    31  	// Parse the keyring and make sure we only have a single private key in it
    32  	keys, err := openpgp.ReadArmoredKeyRing(bytes.NewBufferString(pgpkey))
    33  	if err != nil {
    34  		return err
    35  	}
    36  	if len(keys) != 1 {
    37  		return fmt.Errorf("key count mismatch: have %d, want %d", len(keys), 1)
    38  	}
    39  	// Create the input and output streams for signing
    40  	in, err := os.Open(input)
    41  	if err != nil {
    42  		return err
    43  	}
    44  	defer in.Close()
    45  
    46  	out, err := os.Create(output)
    47  	if err != nil {
    48  		return err
    49  	}
    50  	defer out.Close()
    51  
    52  	// Generate the signature and return
    53  	return openpgp.ArmoredDetachSign(out, keys[0], in, nil)
    54  }