All or nothings 1 Brute-force attack 1 Cryptography 1 Electronic mail 1 Information security 1 Information theory 1 Information- theoretic securities Perfect securities 1 Pre-processing techniques 1 Probability distribution 1 Probability distributions 1 Probability: distributions 1 Random variables 1 Security 1 Security of data 1 Security properties 1 Transforms 1 Unconditionally secure 1 Upper Bound 1 Upper bound 1