Also check out the hints for the small examples.

For the first and third ones, it may be helpful to assign letters to each of the symbols to start with so that it's easier to see the "alphabet" you're working with.

Sometimes, when you have a group of messages from the same person, there will be a predictable piece of plaintext at a certain place in the text. If you know this, you can easily decipher that plaintext. Such a piece of known plaintext is called a crib.

Do you know any of these ciphers?

If you're feeling lazy, here are the frequency counts for the four ciphers on the challenge sheet.

• Frequency counts for the first cipher
• Frequency counts for the second cipher
• Frequency counts for the third cipher
• Frequency counts for the fourth cipher

First cipher

Second cipher

Atbash data
Letters		Digraphs
V	31	sv	8
S	19	zh	6
Z	18	vi	6
L	18	sz	6
H	14	zm	4
G	14	yz	4
M	12	yv	4
I	10	yb	4
Y	9	xl	4
R	7	vv	4
F	7	sl	4
U	6	ol	4
N	6	nv	4
X	5	mv	4
O	5	mh	4
D	5	lu	4
W	4	lm	4
K	4	ld	4
B	3	kg	4
T	2	hv	4
Q	2
E	2
P	1
A	1

Third cipher

Gold Bug data
Characters		Digraphs
8	33	48	10
;	26	8)	6
4	19	8;	6
#	16	+8	6
)	16	)4	6
*	15	;4	6
5	12	1;	6
6	11	6	6
(	9	(;	6
+	8	88	4
1	6	8*	4
0	6	*8	4
9	5	(8	4
2	5	)6	4
3	4	5)	4
:	4	5;	4
?	3	*#	4
%	2	?;	4
]	1
.	1

Fourth cipher

Caesar shift data
Letters		Digraphs
L	29	VY	6
V	25	PU	6
O	21	HU	6
H	21	AO	6
P	20	YP	5
Y	19	VB	5
A	19	UN	5
Z	18	PZ	5
U	18	OP	5
K	11	OL	5
N	10	OH	5
T	9	YV	4
M	7	YL	4
D	7	VT	4
B	7	UK	4
S	6	LZ	4
J	6	LY	4
I	6	LO	4
W	5	HA	4
F	3	ZA	3
C	3	VM	3
R	2	NO	3
		LP	3
		LJ	3
		LH	3
		IL	3
		HZ	3
		HY	3