00:01
In this question we are going to use the affine cipher to decrypt the following messages where we have been given that e is being coded as y and v is coded as t.
00:15
We have to decode the messages which is given as q a 0 0 o o y q q e v h e q v.
00:26
So let us see how we are going to do this.
00:28
So first of all in affine cipher we know the following things that is ex is equals to a times of x plus b.
00:42
This formula we use and we give from numbers from a to z as 0 to 25.
00:53
A corresponds to 0 b corresponds to 1 and so on.
00:56
So from this what we can say a is mapped to y that means 4 is being mapped to y corresponds to 24 and v that is 19 corresponds to t equals to 21.
01:12
Now what we can do here this is the other way y is mapped to e and t is mapped to v.
01:23
So using this equation hence from equation 1 this is the encryption function we get that e of x that is e of 4 is given to be 24 it is equals to 4 times of a plus b.
01:43
Let's say this is equation 2 and we have e of 19 is given to be 21 equals to 4 times 19 plus b.
01:59
A times 19 plus b.
02:01
This is equation 3 from equation 2 and 3 from equation 2 and 3 if we subtract 19 minus 4 is 15 a.
02:13
B will get cancelled equals to 21 minus 24 is minus 3 and this thing operation is addition and subtraction modulo 26.
02:23
So we get this this is same as 15 a congruent to minus 3 is equivalent to 23 modulo 26...