The first method of cipher to discuss is called Caesar cipher or additive cipher. In this technique of encryption, the alphabet slides either to the right or left, so that each letter is replaced by another letter that represents it throughout the message, keeping the alphabet in consecutive order. For example, if "a" is shifted three positions to the left, represented as "X", then "Y" would stand for "b." This means that there are twenty-six different ciphers of this system, one for each letter.

The best way of encoding a Caser cipher is to make a key. First, write the alphabet once in lower case. Then match up the shift to its desired position on the alphabet, writing the cipher alph

Last of all to talk about is a cipher called affine. It can be understood as a method using numbers to compute the code. Affine ciphers consist of both additive and multiplicative cipher qualities. The first step in the process of constructing an alphabet for affine ciphers is to translate an additive cipher into numbers. For example, the letter "a" is equal to one, "b" to two, "c" to three, et cetera, all the way up to twenty-five which is "y" ("z" equals zero). When a shift of three is added to "x", 24 + 3, the result is twenty-seven. Since the alphabet only has twenty-six letters we need to use modulo 26, meaning 27 / 26 has a remainder of one. In mod 26, the remainder is always what one is looking for. One corresponds to the letter "a." So, in a shift of three "x" is one or "a." It was mentioned earlier that there are twenty six different forms of additive ciphers, so keep that in mind for when the variables of affine ciphers are calculated.

Breaking this kind of cipher is also relatively easy since there are only twenty-six different variables of the ciphers. There are methods, however, that can make it much simpler. For instance, certain letters of the alphabet tend to appear more often in the English language. The letter "e" is by far the most common, while "t" is the second. So, by taking tally of how many times the ciphertext letters appear in a secret message, one can often figure out which letter is the "e." The frequency of pairs of letters together can also be utilized. The letters "he" are the most common, often forming the words "he," "she," and "the." If two ciphertext letters tend to turn up in the same order a lot, then it is probable that these two letters make the "he" duo. However, these conclusions can often be wrong. There is no rule saying that "e" and "he" have to exist in a message. And, frequently, when the message is short, neither of these do appear. So, since there are relatively few different ciphers of this method of cipher, it cannot hurt to try each one until one find the right offset to break the code. Also, one can try to count all the characters in the message, making a letter to frequency ratio. When there are ciphertext letters with low frequencies all in a row, that is often a pointer to the letters "v," "w," "x," "y," and "z." The letters "r," "s," and "t" also can be found in a similar way, by finding three letters in consecutive order with high frequencies.

In a multiplicative cipher a person would use the letter "t" to represent a number. Let's say "t" is two. Next, the number which corresponds to the letter, such as one for "a," is multiplied by "t

Some common words found in the essay are:
, 26 remainder, affine ciphers, mod 26, keyword ciphers, relatively easy, ciphertext letters, multiplicative cipher, twelve multiplicative, corresponds letter, method cipher,
Approximate Word count = 1781
Approximate Pages = 7 (250 words per page double spaced)