I'm starting to have a big list of passwords I need safely stored. I was looking at password managers like LastPass, but these always seem to be targetted by hackers and have been compromised before.

Would I lose anything from storing my passwords in a text document that I encrypt myself using AES 256? Then just decrypt when I want the password?

Considering those compromises you mention, do you think that encrypting files yourself will be easy? How do you know you won't get into those same pitfalls that resulted in compromises of password managers?

AES 256 is believed to be computationally secure. Every computer ever made working simultaneously to brute force the key, working since the beginning of time, would have a probabilistically negligible chance of ever finding the key to an encryption.

However: a secure algorithm doesn't guarantee a secure implementation. Just to give you an example, here are a few questions you should ask yourself:


How are you going to ensure that two identical passwords in your list are not encrypted to identical AES ciphertext? (so that if the adversary knows one password, he'll know where it is reused)
Are you sure your decrypted password list cannot be reclaimed by a process allocating RAM after you have consulted your list?
Are you sure your decrypted password list will not end up is the swapfile?
What communication mechanisms will you use between the user providing the master password, the process decrypting the password list and the target application in need of one password?


Password managers are designed with those (and perhaps many others) concerns in mind. It's almost impossible to get everything right when doing it yourself the first time, especially if you're not a security expert.
