open-vault/helper/pgpkeys/encryptshares.go

47 lines
1.5 KiB
Go

package pgpkeys
import (
"bytes"
"encoding/base64"
"encoding/hex"
"fmt"
"golang.org/x/crypto/openpgp"
"golang.org/x/crypto/openpgp/packet"
)
// EncryptShares takes an ordered set of Shamir key share fragments and
// PGP public keys and encrypts each Shamir key fragment with the corresponding
// public key
//
// Note: There is no corresponding test function; this functionality is
// thoroughly tested in the init and rekey command unit tests
func EncryptShares(secretShares [][]byte, pgpKeys []string) ([][]byte, error) {
if len(secretShares) != len(pgpKeys) {
return nil, fmt.Errorf("Mismatch between number of generated shares and number of PGP keys")
}
encryptedShares := [][]byte{}
for i, keystring := range pgpKeys {
data, err := base64.StdEncoding.DecodeString(keystring)
if err != nil {
return nil, fmt.Errorf("Error decoding given PGP key: %s", err)
}
entity, err := openpgp.ReadEntity(packet.NewReader(bytes.NewBuffer(data)))
if err != nil {
return nil, fmt.Errorf("Error parsing given PGP key: %s", err)
}
ctBuf := bytes.NewBuffer(nil)
pt, err := openpgp.Encrypt(ctBuf, []*openpgp.Entity{entity}, nil, nil, nil)
if err != nil {
return nil, fmt.Errorf("Error setting up encryption for PGP message: %s", err)
}
_, err = pt.Write([]byte(hex.EncodeToString(secretShares[i])))
if err != nil {
return nil, fmt.Errorf("Error encrypting PGP message: %s", err)
}
pt.Close()
encryptedShares = append(encryptedShares, ctBuf.Bytes())
}
return encryptedShares, nil
}