does adding extra ;evels of encryption to an already encrypted volume or file make things more secure ? first making an encrypted volume and creating another encrypted volume inside the already encypted volume add to the security ?
Double encryption will double the security, but you will also double the processing power and/or processing time to decrypt the said item. A strong encryption algorithm used with its highest settings should be enough. The only reason to use double encryption is if you believe one of the encryption algorithms may be compromised.
Volume inside volume? Od I understand setup correctly: Yes, but in practice it is not worth the hassle. Just add one more random letter to the password if you need to feel extra secure.
Modern symmetric encryption alghorithms are sound and secure given the user uses encryption tools with caution. For modern sym. encryption user is the weakest link in the chain. Especially habits of user. With 2 volumes you need to remember two unique passwords. Knowing how safe modern symmetric encryption are it is better to just add one more letter to password and focus on not letting anyone eavesdrop on its.
The choice is ultimately up to you, but.... The top encryption algorithms out there (like AES, Twofish, Serpent), when used with their highest setting, provide the ultimate security. It is computationally unfeasible to break them through brute force, using the fastest super computer available today, or any super computer that may be available in the near future. So this is why there is no logical need for double encryption. However, if you just need more security you can go for the Serpent algorithm. Serpent only lost the competition to AES (Rijndael) because its designers decided to lean towards security over performance. Twofish was somewhere in the middle, while Rijndael provided the best balance between security and performance, so it won the competition and became the AES standard. All three are very strong and unbreakable. I personally choose AES, because nowadays all processors provide hardware acceleration for AES, thus making encryption/decryption using AES 4-8 times faster then the other algorithms based on independent tests available on the web. If you really want ultimate security, instead of double encryption, I would recommend using a strong password, a strong hash algorithm (like Whirpool, SHA-3, SHA-512, Blake) and a strong encryption algorithm (like AES, Twofish, Serpent). If you are concerned that your password is not strong, you can use a keyfile (at least 512 bits) with the password. So, even if someone does break your password, they will still need to break the 512 bit keyfile before they can access your data. But like I said in the beginning, the choice is ultimately up to you, if you prefer double encryption, go for it.
