This presentation demonstrate the use of Poem code used by the Britain’s Special Operations Executive (SOE) in World War II. Both Encryption and Decryption process are illustrated with an example

1. THE SOE CODE / POEM CODE
PRESENTED BY
* SAZZAD SAJU *

2. 1. INTRODUCTION (1/1)
• During the second world war, Britain’s special operations
executive (SOE) communicated with agents behind
enemy lines using codes based on poems which is also
known as poem code.
• Sender and Receiver pre-arranges a poem to use.
• Not case-sensitive as codes were send out using Morse
code.
In the next session, we’ll figure out the encryption and
decryption procedure of the poem code:-
2

3. 2. ENCRYPTION AT THE SENDER (1/6)
3
Let’s assume sender-receiver both
agree upon the Jabberwocky Poem

4. 2. ENCRYPTION AT THE SENDER (2/6)
1) For our key, we randomly pick from poem:
• the, all, mome, gyre, twas
2) Indicator group:
• DNUHA
• (the-> 4th word -> 4 gives-> D)
• (all-> 14th word -> 14 gives -> N)
• And so on…. 4

5. 2. ENCRYPTION AT THE SENDER (3/6)
3) Numbering:
5
Finally,
T H E A L L M O M E G Y R E T W A S
15 7 3 1 8 9 10 12 11 4 6 18 13 5 16 17 2 14

6. 2. ENCRYPTION AT THE SENDER (4/6)
6

7. 2. ENCRYPTION AT THE SENDER (5/6)
7

8. 2. ENCRYPTION AT THE SENDER (6/6)
8) Add the indicator group with this, group into five, complete:
8
[Send out]
dnuha eesde tugym oacan nchis eoelx nsjmh
yiocn hdani etead cremh asvs

9. 3. DECRYPTION AT THE RECIPIENT (1/6)
WE GET: DNUHA EESDE TUGYM OACAN NCHIS EOELX NSJMH YIOCN
HDANI ETEAD CREMH ASVS
1) From group indicator generate the key:
• DNUHA -> 4 14 21 8 1
• From poem selected words:
• the, all, mome, gyre, twas
9

10. 3. DECRYPTION AT THE RECIPIENT (2/6)
2) Numbering: (same as before-
slide5)
10
T H E A L L M O M E G Y R E T W A S
15 7 3 1 8 9 10 12 11 4 6 18 13 5 16 17 2 14

11. 3. DECRYPTION AT THE RECIPIENT (3/6)
3) Fill Column with Cipher:
• Cipher: eesde tugym oacan nchis eoelx nsjmh yiocn hdani etead cremh asvs
• (Total column of key 18, elements in cipher = 54:: so row= 54/18 = 3)
• Cipher: ees det ugy moa can nch ise oel xns jmh yio cnh dan iet ead cre mha
svs
11
T H E A L L M O M E G Y R E T W A S
15 7 3 1 8 9 10 12 11 4 6 18 13 5 16 17 2 14
e i u e o x j c y m n s d c c m d i
a s g e e n m n i o c v a a r h e e
d e y s l s h h o a h s n n e a t t
[Fill
column1,
column2
and so
on..]

12. 3. DECRYPTION AT THE RECIPIENT (4/6)
4) Read row wise (row1, row 2 and so on):
12
T H E A L L M O M E G Y R E T W A S
15 7 3 1 8 9 10 12 11 4 6 18 13 5 16 17 2 14
e i u e o x j c y m n s d c c m d i
a s g e e n m n i o c v a a r h e e
d e y s l s h h o a h s n n e a t t
eiu eox jcy mns dcc mdi asg een mni ocv aar
hee dey sls hho ahs nne att
Row Wise (row1, row2 so
on):
[Table
from step
3]

13. 3. DECRYPTION AT THE RECIPIENT (5/6)
5) Fill column with cipher from step 4
• cipher: eiu eox jcy mns dcc mdi asg een mni ocv aar hee dey sls hho ahs nne
att
13
T H E A L L M O M E G Y R E T W A S
15 7 3 1 8 9 10 12 11 4 6 18 13 5 16 17 2 14
h a j e e m o h a m m a d d a n e s
h s c i e n c e a n d t e c h n o l
o g y u n i v e r s i t y c s e x s
6) Read row wise:
hajee mohammad danesh science and
technology university cse xs

14. 3. DECRYPTION AT THE RECIPIENT (6/6)
* Remove null characters i.e. ‘xs’
14
[Original Message]
HAJEE MOHAMMAD DANESH SCIENCE AND
TECHNOLOGY UNIVERSITY CSE

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Profile
Name: Sazzad Saju
CSE, Hajee Mohammad
Danesh Science and
Technology University,
Dinajpur, Bangladesh