I intend to use cloud storage for some of my application logs. These logs might contain confidential business data, so I would like to encrypt them prior to upload.
For security reasons, I prefer using large symmetric key cryptography over simple password encryption.
Do you know any Fast, reliable, open source encryption tool for ubuntu?
As you asked for a symmetric solution:
I would advise using AES as the symmetric crypto algorithm. On Ubuntu you could use aespipe (should be in the official repository) or AES Crypt. That leaves you with the task of managing your secret key(s). If you can store them secure locally, everything is fine.
If you want to store your secrect keys encrypted, i would use an asymmetric tool like GPG as SvenW suggested. As GPG can use AES as symmetric backend, there is no need to do the AES stuff yourself. Just let GPG do that.
