Bacon's cipher or the Baconian cipher is a method of steganography (a method of hiding a secret message as opposed to a true cipher) devised by Francis Bacon. To encode a message, each letter of the plaintext is replaced by a group of five of the letters 'A' or 'B'. This replacement is done according to the alphabet of the Baconian cipher, shown below. More on Wikipedia.

I=J and U=V
Separated letters

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A	B	C	D	E	F	G	H	I=J	K	L	M
AAAAA	AAAAB	AAABA	AAABB	AABAA	AABAB	AABBA	AABBB	ABAAA	ABAAB	ABABA	ABABB
N	O	P	Q	R	S	T	U=V	W	X	Y	Z
ABBAA	ABBAB	ABBBA	ABBBB	BAAAA	BAAAB	BAABA	BAABB	BABAA	BABAB	BABBA	BABBB

A

B

C

D

E

F

G

H

I

J

K

L

M

AAAAA

AAAAB

AAABA

AAABB

AABAA

AABAB

AABBA

AABBB

ABAAA

ABAAB

ABABA

ABABB

ABBAA

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

ABBAB

ABBBA

ABBBB

BAAAA

BAAAB

BAABA

BAABB

BABAA

BABAB

BABBA

BABBB

BBAAA

BBAAB