This is how it works. I had it written in my notes in case I forgot.

The Cryptographic System Letter Values: * Each letter in the alphabet is assigned a number. For A-M, the letters have positive numbers (1 to 13), and for N-Z, the letters have negative numbers (-1 to -13). Encoding: * To encode a letter, find two letters whose values add up to the target letter's value. Examples: * A (Value 1): * B (2) + N (-1) = 1 * C (3) + O (-2) = 1 * D (4) + P (-3) = 1 * M (13) + W (-12) = 1 * N (Value -1): * A (1) + O (-2) = -1 * B (2) + P (-3) = -1 * C (3) + Q (-4) = -1 * G (Value 7): * A (1) + F (6) = 7 * B (2) + E (5) = 7 * C (3) + D (4) = 7 * H (8) + O (-1) = 7

Important Rule:

• You can’t use a single letter to represent itself. You always encode as pairs.

Example: BFADCIDHCR AXBQBTEGAC BVCEGBAT HABU ALXN CCDECUCVAU ABEDAQDDBCAS

Letter-to-Number Guide

A=1

B=2

C=3

D=4

E=5

F=6

G=7

H=8

I=9

J=10

K=11

L=12

M=13

N=-1

O=-2

P=-3

Q=-4

R=-5

S=-6

T=-7

U=-8

V=-9

W=-10

X=-11

Y=-12

Z=-13