Character Ciphers -The original cipher. This was actually used throughout
history, long before computers. It involves taking a string of characters
and replacing one character with another. You could then reference the
cipher table to determine which ciphertext character means the actual
letter being communicated. Of course, this isn't a very secure way of
sending a message. You could just replace letters until something makes
sense. For example, vowels in English are used regularly, and probably
would be the first identified letter. This was a great way to secure a
message before most of the population learned how to read and write.
Block Ciphers -Takes a "block" of data, usually 128-bit blocks, and encodes
it using an algorithm. Sort of like a character cipher, this is taking a chunk
of data, converting it to numbers, then applying a math problem to it. The
reason this method is so secure is because the math problem used is
extremely difficult to reverse engineer.+
Stream Ciphers -This is used for encoded data being sent over a best effort
transportation medium, such as UDP. As a result, this is often used for
video and audio streaming. Takes one bit of data and encodes it, then
sends it.+
