libgocryptfs/internal/configfile/kdf.go
Jakob Unterwurzacher 0c80cca674 toggledlog: convert remaing naked fmt.Print*
Several fatal errors were just printed to stdout, which
meant they were invisible when running the test suite.

Fix this by introducing toggledlog.Fatal and convert as
follows:

Fatal errors     -> toggledlog.Fatal
Warnings         -> toggledlog.Warn
Password prompts -> fmt.Fprintf
2016-06-05 14:32:07 +02:00

59 lines
1.2 KiB
Go

package configfile
import (
"log"
"math"
"os"
"golang.org/x/crypto/scrypt"
"github.com/rfjakob/gocryptfs/internal/cryptocore"
"github.com/rfjakob/gocryptfs/internal/toggledlog"
)
const (
// 1 << 16 uses 64MB of memory,
// takes 4 seconds on my Atom Z3735F netbook
ScryptDefaultLogN = 16
)
type scryptKdf struct {
Salt []byte
N int
R int
P int
KeyLen int
}
func NewScryptKdf(logN int) scryptKdf {
var s scryptKdf
s.Salt = cryptocore.RandBytes(cryptocore.KeyLen)
if logN <= 0 {
s.N = 1 << ScryptDefaultLogN
} else {
if logN < 10 {
toggledlog.Fatal.Println("Error: scryptn below 10 is too low to make sense. Aborting.")
os.Exit(1)
}
s.N = 1 << uint32(logN)
}
s.R = 8 // Always 8
s.P = 1 // Always 1
s.KeyLen = cryptocore.KeyLen
return s
}
func (s *scryptKdf) DeriveKey(pw string) []byte {
k, err := scrypt.Key([]byte(pw), s.Salt, s.N, s.R, s.P, s.KeyLen)
if err != nil {
log.Panicf("DeriveKey failed: %v", err)
}
return k
}
// LogN - N is saved as 2^LogN, but LogN is much easier to work with.
// This function gives you LogN = Log2(N).
func (s *scryptKdf) LogN() int {
return int(math.Log2(float64(s.N)) + 0.5)
}