// GetKeyAES returns the RSA private key of the record given the correct password.
func (pr PasswordRecord) GetKeyRSA(password string) (key rsa.PrivateKey, err error) {
if pr.Type != RSARecord {
return key, errors.New("Invalid function for record type")
}
err = pr.ValidatePassword(password)
if err != nil {
return
}
passKey, err := derivePasswordKey(password, pr.KeySalt)
if err != nil {
return
}
rsaExponentPadded, err := decryptCBC(pr.RSAKey.RSAExp, pr.RSAKey.RSAExpIV, passKey)
if err != nil {
return
}
rsaExponent, err := padding.RemovePadding(rsaExponentPadded)
if err != nil {
return
}
rsaPrimePPadded, err := decryptCBC(pr.RSAKey.RSAPrimeP, pr.RSAKey.RSAPrimePIV, passKey)
if err != nil {
return
}
rsaPrimeP, err := padding.RemovePadding(rsaPrimePPadded)
if err != nil {
return
}
rsaPrimeQPadded, err := decryptCBC(pr.RSAKey.RSAPrimeQ, pr.RSAKey.RSAPrimeQIV, passKey)
if err != nil {
return
}
rsaPrimeQ, err := padding.RemovePadding(rsaPrimeQPadded)
if err != nil {
return
}
key.PublicKey = pr.RSAKey.RSAPublic
key.D = big.NewInt(0).SetBytes(rsaExponent)
key.Primes = []*big.Int{big.NewInt(0), big.NewInt(0)}
key.Primes[0].SetBytes(rsaPrimeP)
key.Primes[1].SetBytes(rsaPrimeQ)
err = key.Validate()
if err != nil {
return
}
return
}
// Decrypt decrypts a file using the keys in the key cache.
func Decrypt(in []byte) (resp []byte, err error) {
// unwrap encrypted file
var encrypted EncryptedFile
if err = json.Unmarshal(in, &encrypted); err != nil {
return
}
if encrypted.Version != DEFAULT_VERSION {
return nil, errors.New("Unknown version")
}
// make sure file was encrypted with the active vault
vaultId, err := passvault.GetVaultId()
if err != nil {
return
}
if encrypted.VaultId != vaultId {
return nil, errors.New("Wrong vault")
}
// validate the size of the keys
for _, multiKey := range encrypted.KeySet {
if len(multiKey.Key) != 16 {
err = errors.New("Invalid Input")
return
}
}
// compute HMAC
hmacKey, err := passvault.GetHmacKey()
if err != nil {
return
}
mac := hmac.New(sha1.New, hmacKey)
mac.Write(encrypted.Data)
expectedMAC := mac.Sum(nil)
if !hmac.Equal(encrypted.Signature, expectedMAC) {
err = errors.New("Signature mismatch")
return
}
// decrypt file key with delegate keys
var unwrappedKey = make([]byte, 16)
if unwrappedKey, err = unwrapKey(encrypted.KeySet, encrypted.KeySetRSA); err != nil {
return
}
aesCrypt, err := aes.NewCipher(unwrappedKey)
if err != nil {
return
}
clearData := make([]byte, len(encrypted.Data))
aesCBC := cipher.NewCBCDecrypter(aesCrypt, encrypted.IV)
// decrypt contents of file
aesCBC.CryptBlocks(clearData, encrypted.Data)
return padding.RemovePadding(clearData)
}
