Re: scrypt: Decrypting file would require too much memory

[Colin Percival <cperciva@tarsnap.com>]

On 10/14/15 00:45, Christoph Borsbach wrote:
> I have a simple question regarding the scrypt utility. I use it to encrypt
> and decrypt a small textfile, which changes from time to time. Since the last
> change I made to the file I get the following error when I try to "dec" the
> file: 
> 
> scrypt: Decrypting file would require too much memory
> 
> I tried to play around with the -m and -M options, but no matter how much
> memory I grant scrypt, the error persists. This is scrypt-1.1.6 on an OpenBSD
> 5.7 system. Now, the same file decrypts fine on an Ubuntu Linux System with
> scrypt 1.1.6., so I can get to the data, no problem. The file is very small,
> just a 100 lines of test, if that. 

How much memory does this system have?  Did you encrypt the file on the same
system?  If you encrypt a new file now, can you decrypt it?  Has anything
changed on the system since you encrypted the file?

The scrypt code makes some awkward attempts to figure out how much memory is
"available"; unfortunately there isn't any really good way to figure this out
(and indeed the concept isn't even entirely well-defined).  The most likely
scenario here is that the scrypt code is thinking that you have very little
available memory.

-- 
Colin Percival
Security Officer Emeritus, FreeBSD | The power to serve
Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid