How to cryptoanalyze a one time pad that uses a plain text document as the pad?

I have read that in order for a one time pad to be truly secure, the pad itself must be random data. Given the practical difficulty of sharing a secure random pad, I was wondering what would be the problems with using the va… Continue reading How to cryptoanalyze a one time pad that uses a plain text document as the pad?

What kinds of encryption are _not_ breakable via Quantum Computers?

There’s the recent article NSA seeks to build quantum computer that could crack most types of encryption. Now I’m not surprised by the NSA trying anything1, but what slightly baffles me is the word “most” – so, what encryptio… Continue reading What kinds of encryption are _not_ breakable via Quantum Computers?

At what point does adding more iterations to PBKDF2 provide no extra security?

If my true passphrase is used only to generate a hash which is used as the cipher’s actual key, doesn’t that mean it’s possible to try and brute force the cipher itself? I know it would take an impossibly long time either way… Continue reading At what point does adding more iterations to PBKDF2 provide no extra security?

Where can I learn cryptography/cryptanalysis the hard way, without going to school ? Any good book?

I’m not so bad at mathematics:

I know what are p-list and p-combinations, I know matrix algebra, I know what a XOR is, I know how to tell if number is a prime, etc: I’m not the programmer who hates math because he is bad at … Continue reading Where can I learn cryptography/cryptanalysis the hard way, without going to school ? Any good book?