1. Straddling Checkerboard Cipher encoder

Text : ABCD efghi
Table Alphabet Key : abcdefghijklmnopqrstuvwxyz
Numeric Key : 0123456789
Row-2 digit : 4
Row-3 digit : 6

Solution:

The checkerboard with the key alphabet in order and the blanks at 4 and 6.

	0	1	2	3	4	5	6	7	8	9
	A	B	C	D		E		F	G	H
4	I	J	K	L	M	N	O	P	Q	R
6	S	T	U	V	W	X	Y	Z

The plaintext is then converted to numbers by locating them in the grid.
If letter is in row-1 then cipher number is column digit only.
If letter is in row-2 or row-3 then cipher number is row digit followed by column digit.

Each char and its digit code

Plaintext	A	B	C	D		E	F	G	H	I
Ciphertext	0	1	2	3		5	7	8	9	40

So finally

Plaintext	: ABCD EFGHI
Ciphertext	: 0123 578940

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2. Straddling Checkerboard Cipher encoder

Text : hello world
Table Alphabet Key : abcdefghijklmnopqrstuvwxyz
Numeric Key : 0123456789
Row-2 digit : 4
Row-3 digit : 6

Solution:

The checkerboard with the key alphabet in order and the blanks at 4 and 6.

	0	1	2	3	4	5	6	7	8	9
	A	B	C	D		E		F	G	H
4	I	J	K	L	M	N	O	P	Q	R
6	S	T	U	V	W	X	Y	Z

The plaintext is then converted to numbers by locating them in the grid.
If letter is in row-1 then cipher number is column digit only.
If letter is in row-2 or row-3 then cipher number is row digit followed by column digit.

Each char and its digit code

Plaintext	H	E	L	L	O		W	O	R	L	D
Ciphertext	9	5	43	43	46		64	46	49	43	3

So finally

Plaintext	: HELLO WORLD
Ciphertext	: 95434346 644649433