## On the Subject of the Caesar Shuffle CM

If the Submit Button is white, follow the instructions under Encrypt Instructions. Otherwise follow the instructions under Decrypt Instructions.

#### Encrypt Instructions

• Reverse both keywords on screens 1 and 2.
• Let X equal to the alphabetic position (A1Z26) of the Nth letter of the keyword on screen 1, modulo the encrypted word's length minus 1, plus 1.
• Subtract the encrypted word's length by X to get a new X value.
• Place a pivot after the Xth letter in the encrypted word.
• Swap the 2 strings to the left and right of the pivot.
• Shift the now-right substring backwards in the alphabet by the alphabetic position (A1Z26) of the current letter of the second key. Remove the pivot.
• Do this for each letter of the 2 keywords to get a decrypted word.

#### Decrypt Instructions

• Place a pivot after the Xth letter in the encrypted word. X is equal to the alphabetic position of the Nth letter of the keyword on screen 1 (A1Z26), modulo the encrypted word's length minus 1, plus 1.
• Swap the 2 strings to the left and right of the pivot.
• Shift the now-left substring forwards in the alphabet by the alphabetic position (A1Z26) of the Nth letter of the keyword on screen 2. Remove the pivot.
• Do this for each letter of the 2 keywords to get a decrypted word.

#### Example 1

Encrypted Word: QOHGWYQ
Screen 1: FEINT
Screen 2: CLOAK
Using Encrypt Rules

T → (20 % (7 - 1)) + 1 → 7 - 3 → 4

QOHG.WYQ → WYQ.QOHG - K(11) → WYQ.FDWV → WYQFDWV

N → (14 % (7 - 1)) + 1 → 7 - 3 → 4

WYQF.DWV → DWV.WYQF - A(1) → DWV.VXPE → DWVVXPE

I → (9 % (7 - 1)) + 1 → 7 - 4 → 3

DWV.VXPE → VXPE.DWV - O(15) → VXPE.OHG → VXPEOHG

E → (5 % (7 - 1)) + 1 → 7 - 6 → 1

V.XPEOHG → XPEOHG.V - L(12) → XPEOHG.J → XPEOHGJ

F → (6 % (7 - 1)) + 1 → 7 - 1 → 6

XPEOHG.J → J.XPEOHG - C(3) → J.UMBLED → JUMBLED

Decrypted Word: JUMBLED

#### Example 2

Encrypted Word: YIVUUV
Screen 1: GRATER
Screen 2: LEVELS
Using Decrypt Rules

G → (7 % (6 - 1)) + 1 → 3

YIV.UUV → UUV.YIV + L(12) → GGH.YIV → GGHYIV

R → (18 % (6 - 1)) + 1 → 4

GGHY.IV → IV.GGHY + E(5) → NA.GGHY → NAGGHY

A → (1 % (6 - 1)) + 1 → 2

NA.GGHY → GGHY.NA + V(22) → CCDU.NA → CCDUNA

T → (20 % (6 - 1)) + 1 → 1

C.CDUNA → CDUNA.C + E(5) → HIZSF.C → HIZSFC

E → (5 % (6 - 1)) + 1 → 1

H.IZSFC → IZSFC.H + L(12) → ULERO.H → ULEROH

R → (18 % (6 - 1)) + 1 → 4

ULER.OH → OH.ULER + S(19) → HA.ULER → HAULER

Decrypted Word: HAULER

You can use this table as a way to get your decrypted letters. To do so, follow the instructions below:

• Use the keyword's letter as the row.
• If you are adding, use the encrypted word's letter as the column. The intersection of the 2 will be your decrypted letter.
• If you are subtracting, find the encrypted word's letter within the row. The column that the letter is in becomes your decrypted letter.
ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCDEFGHIJKLMNOPQRSTUVWXYZA
BCDEFGHIJKLMNOPQRSTUVWXYZAB
CDEFGHIJKLMNOPQRSTUVWXYZABC
DEFGHIJKLMNOPQRSTUVWXYZABCD
EFGHIJKLMNOPQRSTUVWXYZABCDE
FGHIJKLMNOPQRSTUVWXYZABCDEF
GHIJKLMNOPQRSTUVWXYZABCDEFG
HIJKLMNOPQRSTUVWXYZABCDEFGH
IJKLMNOPQRSTUVWXYZABCDEFGHI
JKLMNOPQRSTUVWXYZABCDEFGHIJ
KLMNOPQRSTUVWXYZABCDEFGHIJK
LMNOPQRSTUVWXYZABCDEFGHIJKL
MNOPQRSTUVWXYZABCDEFGHIJKLM
NOPQRSTUVWXYZABCDEFGHIJKLMN
OPQRSTUVWXYZABCDEFGHIJKLMNO
PQRSTUVWXYZABCDEFGHIJKLMNOP
QRSTUVWXYZABCDEFGHIJKLMNOPQ
RSTUVWXYZABCDEFGHIJKLMNOPQR
STUVWXYZABCDEFGHIJKLMNOPQRS
TUVWXYZABCDEFGHIJKLMNOPQRST
UVWXYZABCDEFGHIJKLMNOPQRSTU
VWXYZABCDEFGHIJKLMNOPQRSTUV
WXYZABCDEFGHIJKLMNOPQRSTUVW
XYZABCDEFGHIJKLMNOPQRSTUVWX
YZABCDEFGHIJKLMNOPQRSTUVWXY
ZABCDEFGHIJKLMNOPQRSTUVWXYZ