Further explain the use of 'scryptn' parameter (#94)

* Further explain the use of 'scryptn' parameter

* Further explain the use of 'scryptn' parameter in MANPAGE

* Use 28 as reasonable upper limit

2 files changed, 5 insertions, 5 deletions

diff --git a/Documentation/MANPAGE.md b/Documentation/MANPAGE.md
index 7387424..fe2d73f 100644
--- a/Documentation/MANPAGE.md
+++ b/Documentation/MANPAGE.md
@@ -200,9 +200,9 @@ Options:
 	For more details visit https://github.com/rfjakob/gocryptfs/issues/92 .
 
 **-scryptn int**
-:	scrypt cost parameter logN. Setting this to a lower value speeds up
-	mounting but makes the password susceptible to brute-force attacks
-	(default 16)
+:	scrypt cost parameter logN. Possible values: 10-28. Setting this to a lower
+        value speeds up	mounting and reduces its memory needs, but makes
+	the password susceptible to brute-force attacks	(default 16).
 
 **-speed**
 :	Run crypto speed test. Benchmark Go's built-in GCM against OpenSSL
diff --git a/cli_args.go b/cli_args.go
index 04009dc..9414e67 100644
--- a/cli_args.go
+++ b/cli_args.go
@@ -124,8 +124,8 @@ func parseCliOpts() (args argContainer) {
 	flagSet.StringVar(&args.fsname, "fsname", "", "Override the filesystem name")
 	flagSet.IntVar(&args.notifypid, "notifypid", 0, "Send USR1 to the specified process after "+
 		"successful mount - used internally for daemonization")
-	flagSet.IntVar(&args.scryptn, "scryptn", configfile.ScryptDefaultLogN, "scrypt cost parameter logN. "+
-		"A lower value speeds up mounting but makes the password susceptible to brute-force attacks")
+	flagSet.IntVar(&args.scryptn, "scryptn", configfile.ScryptDefaultLogN, "scrypt cost parameter logN. Possible values: 10-28. "+
+		"A lower value speeds up mounting and reduces its memory needs, but makes the password susceptible to brute-force attacks")
 	// Ignored otions
 	var dummyBool bool
 	ignoreText := "(ignored for compatibility)"