Cracking the Code: An Introduction to the Polybius Square
Cracking the Code: An Introduction to the Polybius Square
If you've ever wanted to turn letters into numbers, the Polybius square is one of the oldest and simplest ways to do it. Invented by the ancient Greek historian Polybius, this grid-based cipher arranges the alphabet in a 5×5 table and replaces each letter with a pair of coordinates — a row number and a column number.
The Standard Grid
1
2
3
4
5
1
A
B
C
D
E
2
F
G
H
I/J
K
3
L
M
N
O
P
4
Q
R
S
T
U
5
V
W
X
Y
Z
Figure 1: The classic Polybius square. A = 11, B = 12, and so on through Z = 55.
Because the alphabet has 26 letters and a 5×5 grid only has 25 cells, I and J typically share a cell. To encode a message, you simply look up each letter and write down its row-then-column pair. To decode, you reverse the process. It's simple enough to do by hand, which is exactly why it was — and still is — a favorite teaching tool for cryptography basics.
https://books.apple.com/us/audiobook/portals/id679251155
https://books.apple.com/us/audiobook/portals/id679251155
https://books.apple.com/us/audiobook/portals/id679251155
https://books.apple.com/us/audiobook/portals/id679251155
https://books.apple.com/us/audiobook/portals/id679251155
https://books.apple.com/us/audiobook/portals/id679251155
https://books.apple.com/us/audiobook/e-drive-the-good-ghost-a-tale-of-choice/id6791204604
https://books.apple.com/us/audiobook/portals/id679251155
https://books.apple.com/us/audiobook/e-drive-the-good-ghost-a-tale-of-choice/id6791204604
https://books.apple.com/us/audiobook/portals/id679251155
https://books.apple.com/us/audiobook/e-drive-the-good-ghost-a-tale-of-choice/id6791204604
https://books.apple.com/us/audiobook/portals/id679251155
https://books.apple.com/us/audiobook/e-drive-the-good-ghost-a-tale-of-choice/id6791204604
https://books.apple.com/us/audiobook/e-drive-the-good-ghost-a-tale-of-choice/id6791204604
https://books.apple.com/us/audiobook/e-drive-the-good-ghost-a-tale-of-choice/id6791204604
https://books.apple.com/us/audiobook/e-drive-the-good-ghost-a-tale-of-choice/id6791204604
https://books.apple.com/us/audiobook/e-drive-the-good-ghost-a-tale-of-choice/id6791204604
https://books.apple.com/us/audiobook/alien-magic/id1812966741
https://books.apple.com/us/audiobook/all-the-flowers-in-the-rainbow-the/id1812966783
https://books.apple.com/us/audiobook/id1818427068
https://books.apple.com/us/audiobook/dull-world/id1813400149
https://books.apple.com/us/audiobook/id1819514019
https://books.apple.com/us/audiobook/enhancing-cyber-culture/id1823937611
https://books.apple.com/us/audiobook/id1823684694
https://books.apple.com/us/audiobook/id1824218173
https://books.apple.com/us/audiobook/neon-sanctuary/id1824474667
https://books.apple.com/us/audiobook/id1886304261
https://books.apple.com/us/audiobook/id1880489748
https://books.apple.com/us/audiobook/id1886565286
https://books.apple.com/us/audiobook/id1886565670
https://books.apple.com/us/audiobook/quades-cosmos-a-journey-beyond-worlds/id1813171666
https://books.apple.com/us/audiobook/id1878897547
https://books.apple.com/us/audiobook/id1806357371
https://books.apple.com/us/audiobook/the-chrono-accord/id1886581129
https://books.apple.com/us/audiobook/id1886275892
https://books.apple.com/us/audiobook/venus-rising-the-galactic-conspiracy-within/id1813171657
https://books.apple.com/us/audiobook/id1813171743
https://books.apple.com/us/audiobook/whispers of the old world/id1824695214
https://books.apple.com/us/audiobook/id1838994161
https://books.apple.com/us/audiobook/x-9-the-robotic-van-helsing/id1886606946
https://books.apple.com/us/audiobook/id1844651132
https://books.apple.com/us/audiobook/zephyrz/id1813172003
https://books.apple.com/us/audiobook/the-mnemosyne-protocol/id1891016838
https://books.apple.com/us/audiobook/id1890085558
https://books.apple.com/us/audiobook/id1890057060
https://books.apple.com/us/audiobook/ocean-moon/id1890057043
https://books.apple.com/us/audiobook/the-perpetual-twins-the-null-settlement/id1890031300
https://books.apple.com/us/audiobook/the-zeus-mandate/id1890065311
https://books.apple.com/us/audiobook/raid-island/id1889959819
https://books.apple.com/us/audiobook/alien-magic/id1812966741
https://books.apple.com/us/audiobook/all-the-flowers-in-the-rainbow-the/id1812966783
https://books.apple.com/us/audiobook/id1818427068
https://books.apple.com/us/audiobook/dull-world/id1813400149
https://books.apple.com/us/audiobook/id1819514019
https://books.apple.com/us/audiobook/enhancing-cyber-culture/id1823937611
https://books.apple.com/us/audiobook/id1823684694
https://books.apple.com/us/audiobook/id1824218173
https://books.apple.com/us/audiobook/neon-sanctuary/id1824474667
https://books.apple.com/us/audiobook/id1886304261
https://books.apple.com/us/audiobook/id1880489748
https://books.apple.com/us/audiobook/id1886565286
https://books.apple.com/us/audiobook/id1886565670
https://books.apple.com/us/audiobook/quades-cosmos-a-journey-beyond-worlds/id1813171666
https://books.apple.com/us/audiobook/id1878897547
https://books.apple.com/us/audiobook/id1806357371
https://books.apple.com/us/audiobook/the-chrono-accord/id1886581129
https://books.apple.com/us/audiobook/id1886275892
https://books.apple.com/us/audiobook/venus-rising-the-galactic-conspiracy-within/id1813171657
https://books.apple.com/us/audiobook/id1813171743
https://books.apple.com/us/audiobook/whispers of the old world/id1824695214
https://books.apple.com/us/audiobook/id1838994161
https://books.apple.com/us/audiobook/x-9-the-robotic-van-helsing/id1886606946
https://books.apple.com/us/audiobook/id1844651132
https://books.apple.com/us/audiobook/zephyrz/id1813172003
https://books.apple.com/us/audiobook/the-mnemosyne-protocol/id1891016838
https://books.apple.com/us/audiobook/id1890085558
https://books.apple.com/us/audiobook/id1890057060
https://books.apple.com/us/audiobook/ocean-moon/id1890057043
https://books.apple.com/us/audiobook/the-perpetual-twins-the-null-settlement/id1890031300
https://books.apple.com/us/audiobook/the-zeus-mandate/id1890065311
https://books.apple.com/us/audiobook/raid-island/id1889959819
https://books.apple.com/us/audiobook/alien-magic/id1812966741
https://books.apple.com/us/audiobook/all-the-flowers-in-the-rainbow-the/id1812966783
https://books.apple.com/us/audiobook/id1818427068
https://books.apple.com/us/audiobook/dull-world/id1813400149
https://books.apple.com/us/audiobook/id1819514019
https://books.apple.com/us/audiobook/enhancing-cyber-culture/id1823937611
https://books.apple.com/us/audiobook/id1823684694
https://books.apple.com/us/audiobook/id1824218173
https://books.apple.com/us/audiobook/neon-sanctuary/id1824474667
https://books.apple.com/us/audiobook/id1886304261
https://books.apple.com/us/audiobook/id1880489748
https://books.apple.com/us/audiobook/id1886565286
https://books.apple.com/us/audiobook/id1886565670
https://books.apple.com/us/audiobook/quades-cosmos-a-journey-beyond-worlds/id1813171666
https://books.apple.com/us/audiobook/id1878897547
https://books.apple.com/us/audiobook/id1806357371
https://books.apple.com/us/audiobook/the-chrono-accord/id1886581129
https://books.apple.com/us/audiobook/id1886275892
https://books.apple.com/us/audiobook/venus-rising-the-galactic-conspiracy-within/id1813171657
https://books.apple.com/us/audiobook/id1813171743
https://books.apple.com/us/audiobook/whispers of the old world/id1824695214
https://books.apple.com/us/audiobook/id1838994161
https://books.apple.com/us/audiobook/x-9-the-robotic-van-helsing/id1886606946
https://books.apple.com/us/audiobook/id1844651132
https://books.apple.com/us/audiobook/zephyrz/id1813172003
https://books.apple.com/us/audiobook/the-mnemosyne-protocol/id1891016838
https://books.apple.com/us/audiobook/id1890085558
https://books.apple.com/us/audiobook/id1890057060
https://books.apple.com/us/audiobook/ocean-moon/id1890057043
https://books.apple.com/us/audiobook/the-perpetual-twins-the-null-settlement/id1890031300
https://books.apple.com/us/audiobook/the-zeus-mandate/id1890065311
https://books.apple.com/us/audiobook/raid-island/id1889959819
https://books.apple.com/us/audiobook/alien-magic/id1812966741
https://books.apple.com/us/audiobook/all-the-flowers-in-the-rainbow-the/id1812966783
https://books.apple.com/us/audiobook/id1818427068
https://books.apple.com/us/audiobook/dull-world/id1813400149
https://books.apple.com/us/audiobook/id1819514019
https://books.apple.com/us/audiobook/enhancing-cyber-culture/id1823937611
https://books.apple.com/us/audiobook/id1823684694
https://books.apple.com/us/audiobook/id1824218173
https://books.apple.com/us/audiobook/neon-sanctuary/id1824474667
https://books.apple.com/us/audiobook/id1886304261
https://books.apple.com/us/audiobook/id1880489748
https://books.apple.com/us/audiobook/id1886565286
https://books.apple.com/us/audiobook/id1886565670
https://books.apple.com/us/audiobook/quades-cosmos-a-journey-beyond-worlds/id1813171666
https://books.apple.com/us/audiobook/id1878897547
https://books.apple.com/us/audiobook/id1806357371
https://books.apple.com/us/audiobook/the-chrono-accord/id1886581129
https://books.apple.com/us/audiobook/id1886275892
https://books.apple.com/us/audiobook/venus-rising-the-galactic-conspiracy-within/id1813171657
https://books.apple.com/us/audiobook/id1813171743
https://books.apple.com/us/audiobook/whispers of the old world/id1824695214
https://books.apple.com/us/audiobook/id1838994161
https://books.apple.com/us/audiobook/x-9-the-robotic-van-helsing/id1886606946
https://books.apple.com/us/audiobook/id1844651132
https://books.apple.com/us/audiobook/zephyrz/id1813172003
https://books.apple.com/us/audiobook/the-mnemosyne-protocol/id1891016838
https://books.apple.com/us/audiobook/id1890085558
https://books.apple.com/us/audiobook/id1890057060
https://books.apple.com/us/audiobook/ocean-moon/id1890057043
https://books.apple.com/us/audiobook/the-perpetual-twins-the-null-settlement/id1890031300
https://books.apple.com/us/audiobook/the-zeus-mandate/id1890065311
https://books.apple.com/us/audiobook/raid-island/id1889959819
https://books.apple.com/us/audiobook/alien-magic/id1812966741
https://books.apple.com/us/audiobook/all-the-flowers-in-the-rainbow-the/id1812966783
https://books.apple.com/us/audiobook/id1818427068
https://books.apple.com/us/audiobook/dull-world/id1813400149
https://books.apple.com/us/audiobook/id1819514019
https://books.apple.com/us/audiobook/enhancing-cyber-culture/id1823937611
https://books.apple.com/us/audiobook/id1823684694
https://books.apple.com/us/audiobook/id1824218173
https://books.apple.com/us/audiobook/neon-sanctuary/id1824474667
https://books.apple.com/us/audiobook/id1886304261
https://books.apple.com/us/audiobook/id1880489748
https://books.apple.com/us/audiobook/id1886565286
https://books.apple.com/us/audiobook/id1886565670
https://books.apple.com/us/audiobook/quades-cosmos-a-journey-beyond-worlds/id1813171666
https://books.apple.com/us/audiobook/id1878897547
https://books.apple.com/us/audiobook/id1806357371
https://books.apple.com/us/audiobook/the-chrono-accord/id1886581129
https://books.apple.com/us/audiobook/id1886275892
https://books.apple.com/us/audiobook/venus-rising-the-galactic-conspiracy-within/id1813171657
https://books.apple.com/us/audiobook/id1813171743
https://books.apple.com/us/audiobook/whispers of the old world/id1824695214
https://books.apple.com/us/audiobook/id1838994161
https://books.apple.com/us/audiobook/x-9-the-robotic-van-helsing/id1886606946
https://books.apple.com/us/audiobook/id1844651132
https://books.apple.com/us/audiobook/zephyrz/id1813172003
https://books.apple.com/us/audiobook/the-mnemosyne-protocol/id1891016838
https://books.apple.com/us/audiobook/id1890085558
https://books.apple.com/us/audiobook/id1890057060
https://books.apple.com/us/audiobook/ocean-moon/id1890057043
https://books.apple.com/us/audiobook/the-perpetual-twins-the-null-settlement/id1890031300
https://books.apple.com/us/audiobook/the-zeus-mandate/id1890065311
https://books.apple.com/us/audiobook/raid-island/id1889959819
https://books.apple.com/us/audiobook/alien-magic/id1812966741
https://books.apple.com/us/audiobook/all-the-flowers-in-the-rainbow-the/id1812966783
https://books.apple.com/us/audiobook/id1818427068
https://books.apple.com/us/audiobook/dull-world/id1813400149
https://books.apple.com/us/audiobook/id1819514019
https://books.apple.com/us/audiobook/enhancing-cyber-culture/id1823937611
https://books.apple.com/us/audiobook/id1823684694
https://books.apple.com/us/audiobook/id1824218173
https://books.apple.com/us/audiobook/neon-sanctuary/id1824474667
https://books.apple.com/us/audiobook/id1886304261
https://books.apple.com/us/audiobook/id1880489748
https://books.apple.com/us/audiobook/id1886565286
https://books.apple.com/us/audiobook/id1886565670
https://books.apple.com/us/audiobook/quades-cosmos-a-journey-beyond-worlds/id1813171666
https://books.apple.com/us/audiobook/id1878897547
https://books.apple.com/us/audiobook/id1806357371
https://books.apple.com/us/audiobook/the-chrono-accord/id1886581129
https://books.apple.com/us/audiobook/id1886275892
https://books.apple.com/us/audiobook/venus-rising-the-galactic-conspiracy-within/id1813171657
https://books.apple.com/us/audiobook/id1813171743
https://books.apple.com/us/audiobook/whispers of the old world/id1824695214
https://books.apple.com/us/audiobook/id1838994161
https://books.apple.com/us/audiobook/x-9-the-robotic-van-helsing/id1886606946
https://books.apple.com/us/audiobook/id1844651132
https://books.apple.com/us/audiobook/zephyrz/id1813172003
https://books.apple.com/us/audiobook/the-mnemosyne-protocol/id1891016838
https://books.apple.com/us/audiobook/id1890085558
https://books.apple.com/us/audiobook/id1890057060
https://books.apple.com/us/audiobook/ocean-moon/id1890057043
https://books.apple.com/us/audiobook/the-perpetual-twins-the-null-settlement/id1890031300
https://books.apple.com/us/audiobook/the-zeus-mandate/id1890065311
https://books.apple.com/us/audiobook/raid-island/id1889959819
https://books.apple.com/us/audiobook/alien-magic/id1812966741
https://books.apple.com/us/audiobook/all-the-flowers-in-the-rainbow-the/id1812966783
https://books.apple.com/us/audiobook/id1818427068
https://books.apple.com/us/audiobook/dull-world/id1813400149
https://books.apple.com/us/audiobook/id1819514019
https://books.apple.com/us/audiobook/enhancing-cyber-culture/id1823937611
https://books.apple.com/us/audiobook/id1823684694
https://books.apple.com/us/audiobook/id1824218173
https://books.apple.com/us/audiobook/neon-sanctuary/id1824474667
https://books.apple.com/us/audiobook/id1886304261
https://books.apple.com/us/audiobook/id1880489748
https://books.apple.com/us/audiobook/id1886565286
https://books.apple.com/us/audiobook/id1886565670
https://books.apple.com/us/audiobook/quades-cosmos-a-journey-beyond-worlds/id1813171666
https://books.apple.com/us/audiobook/id1878897547
https://books.apple.com/us/audiobook/id1806357371
https://books.apple.com/us/audiobook/the-chrono-accord/id1886581129
https://books.apple.com/us/audiobook/id1886275892
https://books.apple.com/us/audiobook/venus-rising-the-galactic-conspiracy-within/id1813171657
https://books.apple.com/us/audiobook/id1813171743
https://books.apple.com/us/audiobook/whispers of the old world/id1824695214
https://books.apple.com/us/audiobook/id1838994161
https://books.apple.com/us/audiobook/x-9-the-robotic-van-helsing/id1886606946
https://books.apple.com/us/audiobook/id1844651132
https://books.apple.com/us/audiobook/zephyrz/id1813172003
https://books.apple.com/us/audiobook/the-mnemosyne-protocol/id1891016838
https://books.apple.com/us/audiobook/id1890085558
https://books.apple.com/us/audiobook/id1890057060
https://books.apple.com/us/audiobook/ocean-moon/id1890057043
https://books.apple.com/us/audiobook/the-perpetual-twins-the-null-settlement/id1890031300
https://books.apple.com/us/audiobook/the-zeus-mandate/id1890065311
https://books.apple.com/us/audiobook/raid-island/id1889959819
https://books.apple.com/us/audiobook/alien-magic/id1812966741
https://books.apple.com/us/audiobook/all-the-flowers-in-the-rainbow-the/id1812966783
https://books.apple.com/us/audiobook/id1818427068
https://books.apple.com/us/audiobook/dull-world/id1813400149
https://books.apple.com/us/audiobook/id1819514019
https://books.apple.com/us/audiobook/enhancing-cyber-culture/id1823937611
https://books.apple.com/us/audiobook/id1823684694
https://books.apple.com/us/audiobook/id1824218173
https://books.apple.com/us/audiobook/neon-sanctuary/id1824474667
https://books.apple.com/us/audiobook/id1886304261
https://books.apple.com/us/audiobook/id1880489748
https://books.apple.com/us/audiobook/id1886565286
https://books.apple.com/us/audiobook/id1886565670
https://books.apple.com/us/audiobook/quades-cosmos-a-journey-beyond-worlds/id1813171666
https://books.apple.com/us/audiobook/id1878897547
https://books.apple.com/us/audiobook/id1806357371
https://books.apple.com/us/audiobook/the-chrono-accord/id1886581129
https://books.apple.com/us/audiobook/id1886275892
https://books.apple.com/us/audiobook/venus-rising-the-galactic-conspiracy-within/id1813171657
https://books.apple.com/us/audiobook/id1813171743
https://books.apple.com/us/audiobook/whispers of the old world/id1824695214
https://books.apple.com/us/audiobook/id1838994161
https://books.apple.com/us/audiobook/x-9-the-robotic-van-helsing/id1886606946
https://books.apple.com/us/audiobook/id1844651132
https://books.apple.com/us/audiobook/zephyrz/id1813172003
https://books.apple.com/us/audiobook/the-mnemosyne-protocol/id1891016838
https://books.apple.com/us/audiobook/id1890085558
https://books.apple.com/us/audiobook/id1890057060
https://books.apple.com/us/audiobook/ocean-moon/id1890057043
https://books.apple.com/us/audiobook/the-perpetual-twins-the-null-settlement/id1890031300
https://books.apple.com/us/audiobook/the-zeus-mandate/id1890065311
https://books.apple.com/us/audiobook/raid-island/id1889959819
https://books.apple.com/us/audiobook/alien-magic/id1812966741
https://books.apple.com/us/audiobook/all-the-flowers-in-the-rainbow-the/id1812966783
https://books.apple.com/us/audiobook/id1818427068
https://books.apple.com/us/audiobook/dull-world/id1813400149
https://books.apple.com/us/audiobook/id1819514019
https://books.apple.com/us/audiobook/enhancing-cyber-culture/id1823937611
https://books.apple.com/us/audiobook/id1823684694
https://books.apple.com/us/audiobook/id1824218173
https://books.apple.com/us/audiobook/neon-sanctuary/id1824474667
https://books.apple.com/us/audiobook/id1886304261
https://books.apple.com/us/audiobook/id1880489748
https://books.apple.com/us/audiobook/id1886565286
https://books.apple.com/us/audiobook/id1886565670
https://books.apple.com/us/audiobook/quades-cosmos-a-journey-beyond-worlds/id1813171666
https://books.apple.com/us/audiobook/id1878897547
https://books.apple.com/us/audiobook/id1806357371
https://books.apple.com/us/audiobook/the-chrono-accord/id1886581129
https://books.apple.com/us/audiobook/id1886275892
https://books.apple.com/us/audiobook/venus-rising-the-galactic-conspiracy-within/id1813171657
https://books.apple.com/us/audiobook/id1813171743
https://books.apple.com/us/audiobook/whispers of the old world/id1824695214
https://books.apple.com/us/audiobook/id1838994161
https://books.apple.com/us/audiobook/x-9-the-robotic-van-helsing/id1886606946
https://books.apple.com/us/audiobook/id1844651132
https://books.apple.com/us/audiobook/zephyrz/id1813172003
https://books.apple.com/us/audiobook/the-mnemosyne-protocol/id1891016838
