Speed issues when encrypting large file with mcrypt or alternatives

Question

I want to encrypt a 100 GB file on my up to date iMac. It is hard to find out where the temp file is, so I can't find out the progress, but the encryption is already taking a full day. Is this normal? What encryption speed (MB/min) can I expect with a normal machine?

I am currently using mcrypt (from macports) with the command mentioned in the manual for linux crypt compatibility. Is this a good/secure algorithm? Should I use another?

mcrypt -a enigma --keymode scrypt --bare Backup.tar

I want to do backups regularly and encrypt them, so any help is really welcome!

Had the question first on cryptography, but got redirected here.

Answer 1

mcrypt doesn't have any kind of progress or speed indication and data throughput varies greatly due to a large variety of factors. For now you should check if the process hasn't frozen by looking at its processor load. Next time you might want to consider compressing and split archiving your backup file.