pit

use memlimit min for low memory systems

diff --git a/pit.c b/pit.c
index 34b53e8..deea272 100644
--- a/pit.c
+++ b/pit.c
@@ -359,7 +359,16 @@ generate_key(const char *keyfile)
             crypto_pwhash_OPSLIMIT_MODERATE,
             crypto_pwhash_MEMLIMIT_MODERATE,
             crypto_pwhash_ALG_DEFAULT) != 0) {
-        fprintf(stderr, "pit: key derivation failed\n");
+        fprintf(stderr, "pit: key derivation failed - trying with minimal settings\n");
+        if (crypto_pwhash(
+            encrypted + SALT_SIZE, KEY_SIZE,
+            password, pwlen,
+            salt,
+            crypto_pwhash_OPSLIMIT_MIN,
+            crypto_pwhash_MEMLIMIT_MIN,
+            crypto_pwhash_ALG_DEFAULT) != 0) {
+                fprintf(stderr, "pit: key derivation failed - insufficient memory\n");
+            }
         goto cleanup;
     }
 
@@ -466,16 +475,30 @@ read_key_file(const char *path, char **key)
     if (pwlen > 0 && password[pwlen-1] == '\n')
         password[--pwlen] = 0;
 
-    if (crypto_pwhash(
+    int r = crypto_pwhash(
+        decrypted, KEY_SIZE,
+        password, pwlen,
+        encrypted,
+        crypto_pwhash_OPSLIMIT_MODERATE,
+        crypto_pwhash_MEMLIMIT_MODERATE,
+        crypto_pwhash_ALG_DEFAULT);
+
+    if (r != 0) {
+        fprintf(stderr, "pit: trying with minimal memory settings .. \n");
+        r = crypto_pwhash(
             decrypted, KEY_SIZE,
             password, pwlen,
-            encrypted, /* first SALT_SIZE bytes are the salt */
-            crypto_pwhash_OPSLIMIT_SENSITIVE,
-            crypto_pwhash_MEMLIMIT_SENSITIVE,
-            crypto_pwhash_ALG_DEFAULT) != 0) {
-        fprintf(stderr, "pit: key derivation failed\n");
+            encrypted,
+            crypto_pwhash_OPSLIMIT_MIN,
+            crypto_pwhash_MEMLIMIT_MIN,
+            crypto_pwhash_ALG_DEFAULT);
+    }
+
+    if (r !=0) {
+        fprintf(stderr, "pit: key derivation faield - insufficient memory or wrong password\n");
         goto cleanup;
     }
+    
 
     *key = (char*)decrypted;
     decrypted = NULL;