Pcryption

Pcryption is a pen-and-paper cipher designed to encrypt and decrypt text using nothing but a blank sheet of paper.

While it isn't designed to stop professional cryptanalysts, its main good side is simplicity: you do not need to carry a massive lookup table with you to use it. If you understand the underlying pattern, you can encrypt and decrypt entirely from memory.

⚠️ Disclaimer: This project was created for fun Do not use Pcryption to secure sensitive data!

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How It Works

The cipher breaks down letters into a 3-digit code block. Every letter is assigned a code based on three columns that cycle sequentially (Column 1 ➔ Column 2 ➔ Column 3 ➔ Column 1...).

Each 3-digit code [X][Y][Z] is structured like this:

• X (The Group/Row): Dictated by the column cycle.
  • Column 1 uses groups 1, 2, 3
  • Column 2 uses groups 4, 5, 6
  • Column 3 uses groups 7, 8, 9
• Y (The Slot): The specific position (01 through 09) inside that block.
• Z (The Global ID): The raw position of the character in the global 81-character matrix.

Because of this layout, you can easily calculate the codes in your head without looking at the table below.

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Table

Column 1 (Cycle 1)	Column 2 (Cycle 2)	Column 3 (Cycle 3)
101 A 1	401 A 28	701 A 55
102 B 2	402 B 29	702 B 56
103 C 3	403 C 30	703 C 57
104 D 4	404 D 31	704 D 58
105 E 5	405 E 32	705 E 59
106 F 6	406 F 33	706 F 60
107 G 7	407 G 34	707 G 61
108 H 8	408 H 35	708 H 62
109 I 9	409 I 36	709 I 63
---	---	---
201 J 10	501 J 37	801 J 64
202 K 11	502 K 38	802 K 65
203 L 12	503 L 39	803 L 66
204 M 13	504 M 40	804 M 67
205 N 14	505 N 41	805 N 68
206 O 15	506 O 42	806 O 69
207 P 16	507 P 43	807 P 70
208 Q 17	508 Q 44	808 Q 71
209 R 18	509 R 45	809 R 72
---	---	---
301 S 19	601 S 46	901 S 73
302 T 20	602 T 47	902 T 74
303 U 21	603 U 48	903 U 75
304 V 22	604 V 49	904 V 76
305 W 23	605 W 50	905 W 77
306 X 24	606 X 51	906 X 78
307 Y 25	607 Y 52	907 Y 79
308 Z 26	608 Z 53	908 Z 80
309 (Space)	609 (Space)	909 (Space)

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📝 Step-by-Step Example

To encrypt a message, you shift columns for every single letter: Column 1 ➔ Column 2 ➔ Column 3, then restart at Column 1.

Plaintext: Hello I am Chane

Cipher Shift Mapping:

Letter:    H     e     l     l     o    [ ]    I     [ ]    C     h     a     n     e
Cycle:    (1)   (2)   (3)   (1)   (2)   (3)   (1)   (2)   (3)   (1)   (2)   (3)   (1)
Code:     108   405   803   203   506   909   401   609   103   408   701   205   405

Term of use

I don't mind if you use it of modified it feel free to do anytings with it you don't need to credit me since I many people might have same idea (But you could credit me I'll appreciate it)

Note

Hope you have a great day this is my first repo and hope this use full it probably not be really useful but hey enjoy making it and share here