i would have helped u if encryption is of the form (ax+b)modc
but here inclusion of 9 makes it helpless for me
Anyone any good with codebreaking?....
Let plaintext be written in the alphabet a, b, . . . , y, z and let ciphertext be
written in the alphabet A, B, . . . , Y, Z. Both alphabets have N = 26 letters.
Consider the affine cipher on digraphs with encryption
E( ) = 9 + 43mod676:
Encipher the plaintext TRUTHS.
In this question I want to use standard numbering, so A=0, B=1..... Z=25
i can may be help u if u tell me whats use of 9 here
between , see this for some help: http://www.math.cornell.edu/~kozdron...uts/affine.pdf
This is somewhat unusual notation. I've seen people use a letter to denote this, say, .
In any case, you need to represent your digraphs numerically. To do this, you first convert each letter to a number. For the digraph TR, we have and . Then, we write this as a number base 26: . Then pass it through : . Then, .
In summary, the plaintext TR is encrypted into WO. Try the rest for yourself.