Unit 32.2 D2

Comparison of benefits of different cryptography techniques

This technique with use of the algorithm or hash function (algorithm that assigns random data to fixed data) can be used for authentication rather than for data encryption. It takes data as input and with use of one of above techniques creates a hash or a message digest as final product. This hash or message digest is unique for each data. Slightest change to the data should create different hash value. Hash value is small enough for manipulation but big enough to prevent an attempt to encrypt data. Hashing is commonly used in password authentication, even if offender get his hands on the hash value he will be unable to determinate the password because hashing is one way process. Certain hash function can be used to encrypt data and be sending to the receiver who shares the same hash value as sender. Different hash values will shows data differently.

Caesar Cipher is one of the most know cryptography method named after Julius Caesar who used it. He used it with a shift of three to protect messages of military significance. This method was fairly effective since his opponent most of the time would be illiterate or assume that this is some foreign language. This is an example of more complex Caesar Cipher disk. To break the code first we should know the language which from which encryption was made and knowledge about the most frequent letters that occurs in that language. In English it would be “E”, “A”, “R” etc. This means that the most frequent letters in encryption is one of those letters. Now based on the guess user can try to assign to other letters another letter. This can take some time but eventually user will success. Another method would be shifting the letters by one, two etc. until message makes sense. The problem at the Caesar times was that to decode the message algorithm was needed or Caesar Cipher disk which if got into enemy hands would make it easy to decode code. The other...