FAQs:

Is Tresor compatible with 10.7?

No. And no, there won't be a version that will.

Is Tresor compatible with 10.6?

Yes, it is in principle. It will need Rosetta, however, which must be added manually from your 10.6 disk. And please note that Tresor has (with any OS version) the following limitations: It cannot handle long file names (i.e. file names longer than 31 characters) and files bigger than 2 GB.

I occasionally get a system error -47 when encrypting a file, and a message from Tresor that the folder could not be deleted. I would like to know what is causing this error.

This is most likely anti virus software interferring with Tresor. It is recommended to at least turn off any "active scan/auto protect" functionality in your anti virus software before using Tresor.

I get System Error -48 with a note than it could not create a destination file.

This may happen if you try to encrypt files with long file names (more than 31 characters). Tresor actually doesn't support long file names.

Can the author crack files that have been encrypted by Tresor? Is there any back door?

No, our chance to crack a Tresor encrypted file is the same as everyone's. Passphrases and keys are used only in the encryption process and are not stored anywhere. So they may not be recovered. The most promising method to crack a Tresor file is to try commonly used passwords. If the passphrase used for encryption is good (see documentation) the chance to crack the file approaches zero.

Why don't you use algorithm x or y?

Well, simply because we think that IDEA™ is the most secure algorithm publicly available. And please remind that we have to pay royalties to do so. We would do as most developers do and use a free algorithm if we wouldn't think that IDEA™ is the best. Really.

But a 256 or 448 bit algorithm would be more secure.

No, it wouldn't. The most important question about the security of an algorithm is: Is there a weakness in its mathematical properties that might be exploited in order to crack encrypted data? In most cases it is not possible to prove the absence of such weaknesses. But the older an algorithm is and the more often it has been used in crucial applications, the more experts have tried to crack it (without success) and the less likely it is that somebody will find a weakness. Nearly nothing can beat IDEA™ in this, as it has been used over many years in a lot of highly sensitive applications.
Only now, when we must assume that brute force is the most effective way to crack encrypted data, key length comes into consideration. And please note that today it is technically impossible to brute force cipher text that was encrypted with a random 128 bit key within useful time limits. Yes, for a 256 bit key it would be even more impossible. But more impossible than impossible is like getting wetter than wet...

Will the nag screen disappear after registration?

It will, of course.

Is it possible to encrypt a file with your program on a Macintosh and have it decrypted on a PC running Windows 2000?

No, it isn't. Tresor is available only for Macintosh™ and we are not aware of any Windows™ program that can handle Tresor files.

If your question is not answered above, do not hesitate to ask us. For your question please use our feedback form.