[Riflema]

I'd like to ask a (dumb) question: how do they know when they've cracked a password? If they know because the content is suddenly legible, what if you encrypt the content with one method, then encrypt the result using some other method.

Or an I missing something?

[Utilizer]

Encryption doesn’t work that way. Imagine having a bowlful of small 3D shapes such as spheres, cubes, and triangular pyramids. Place a firm sheet over it with cutouts of one shape, say squares. The result will be nothing but cube outputs. Then place all the resulting objects in another bowl and there is only one shape of filter to allow them to pass through again.

Not a perfect example, but it should point out why you have to use the same filter to encrypt and decrypt your files.

[Utilizer]

Just re-read your post. What you are asking about is actually fairly common, and is called a dual-encryption scheme. Encrypting a file more than once using the same or differing passwords for greater security.

Using different passwords makes it more difficult to decrypt your file later if you do not recall which passwords were used and where, however.

There are other methods, but this article is simply discussing passwords, not methods of encryption.

[DuncanWaring]

I’ve wondered that myself.