𝐂𝐨𝐝𝐞𝐬 𝐚𝐧𝐝 𝐂𝐢𝐩𝐡𝐞𝐫𝐬

𝐑𝐨𝐭𝐚𝐭𝐢𝐨𝐧 𝐂𝐨𝐝𝐞

-Type: Substitution
-(Note: it's formula forencryption is f(x)=(ax)mod26 and for decryption is f(y)=a^-1(y)mod26, where x or y corresponds to the position of the letter in the alphabet, e.g. a=0, b=1, c=2.....z=25, mod26 correspond to the limit of the rotation, and a correspond to any input number)
-Example: (encryption)
-Plaintext: KING
-F(x)=(ax)mod26
-a=2
-K=10, f(x)=(2*10)mod26=20
-I =8, f(x)=(2*8)mod26=16
-N=13, f(x)=(2*13)mod26=26
-G=6, f(x)=(2*6)mod26=12
-K=20=U
-I =16=Q
-N=26=A
-G=12=M
-Ciphertext: UQAM
-Example: (decryption)
-Ciphertext: UQAM
-F(y)=a^-1(y)mod26
-a=2
-U=20, f(y)=2^-1(20)mod26=1­0
-Q=16, f(y)=2^-1(16)mod26=8
-A=26, f(y)=2^-1(26)mod26=1­3
-M=12, f(y)=2^-1(12)mod26=6
-U=10=K
-Q=8=I
-A=13=N
-M=6=G
-Plaintext: KING
-(Note: mod26, when no>25, then it will rotate back to 0, 26=0, 27=1, 28=2 and so on, where a=0 and z=25, e.g. 30=e)

~~~CTTRO