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authorJakob Unterwurzacher2015-11-29 18:52:58 +0100
committerJakob Unterwurzacher2015-11-29 18:53:40 +0100
commitbb116282b7db6a6400586d756c6dfdcc8f85fdab (patch)
treef06fe917002c004569c84097595a4c5b357a4407 /cryptfs/kdf.go
parent71bfa1f0fb540790f87faac600e4041052b4d217 (diff)
Add "-scryptn" option that sets the cost parameter for scryptv0.5-rc1
Use that option to speed up the automated tests by 7 seconds. Before: ok github.com/rfjakob/gocryptfs/integration_tests 26.667s After: ok github.com/rfjakob/gocryptfs/integration_tests 19.534s
Diffstat (limited to 'cryptfs/kdf.go')
-rw-r--r--cryptfs/kdf.go22
1 files changed, 19 insertions, 3 deletions
diff --git a/cryptfs/kdf.go b/cryptfs/kdf.go
index 32870cd..73be0bb 100644
--- a/cryptfs/kdf.go
+++ b/cryptfs/kdf.go
@@ -1,6 +1,8 @@
package cryptfs
import (
+ "os"
+ "math"
"fmt"
"golang.org/x/crypto/scrypt"
)
@@ -8,7 +10,7 @@ import (
const (
// 1 << 16 uses 64MB of memory,
// takes 4 seconds on my Atom Z3735F netbook
- SCRYPT_DEFAULT_N = 1 << 16
+ SCRYPT_DEFAULT_LOGN = 16
)
type scryptKdf struct {
@@ -19,10 +21,18 @@ type scryptKdf struct {
KeyLen int
}
-func NewScryptKdf() scryptKdf {
+func NewScryptKdf(logN int) scryptKdf {
var s scryptKdf
s.Salt = RandBytes(KEY_LEN)
- s.N = SCRYPT_DEFAULT_N
+ if logN <= 0 {
+ s.N = 1 << SCRYPT_DEFAULT_LOGN
+ } else {
+ if logN < 10 {
+ fmt.Printf("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 = KEY_LEN
@@ -36,3 +46,9 @@ func (s *scryptKdf) DeriveKey(pw string) []byte {
}
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)
+}