Choose Passphrase and Algorithm

Choosing the right passphrase

Your passphrase is the most important factor influencing the security of your files. This means that it is absolutely unacceptable to use weak passphrases, i.e. short or easy-to-guess ones. If your passphrase is in the dictionary, you are definitely in jeopardy. It is highly recommended that you use a long and unusual passphrase containing upper and lower case letters, numbers, spaces, and punctuation marks, preferably something that you can easily remember but that others cannot guess. In other words "Hello" or "My computer" are bad passphrases, while something like "is 1t TiMe to ch00z someth!ng bet-ter 4 you&me?" is good (don't use this one though!). It's also a good idea to mix your native language with foreign words and use non-English characters.

Which encryption algorithm should I choose?

In fact it's a difficult question. Given today's understanding of cryptography, all the four algorithms used in DigiSecret are unbreakable in the foreseeable future. CAST-128 has been proven to be resistant to both linear and differential cryptanalysis and can be broken only by brute force. Twofish and Blowfish, developed by a famous security expert Bruce Schneier, are also good and fast ciphers with no known weaknesses. Rijndael is the winner of the AES (Advanced Encryption Standard) contest and will soon become the standard in the USA. If we assume that these algorithms can be broken only by brute force, 128-bit keys will be able to withstand attacks for many decades, while 448-bit keys make attacks against them impossible even in theory.