Transposition cipher

A transposition cipher encodes a message by reordering the plaintext. The receiver decodes the message using the inverse transposition.

A simple kind of transposition cipher writes the message into a rectangle by rows and reads it out by columns.

Asimplekin
doftranspo
sitionciph
erwritesth
emessagein
toarectang
lebyrowsan
dreadsitou
tbycolumns

Adsee tldts oirmo erbif tweab eymti rsrya cproi serdo lanta cosle ncegt wiuks iseas tmipp tinao nnohh ngnus. This cipher is often complicated by permuting the rows and columns.

Another cipher uses a grille. This is a square with holes in it such that each cell in the square appears in no more than one position when the grille is rotated to each of its four positions. As much message as will fit in the grille is written, then it is turned to another position and more message is written.

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See also:

• Substitution cipher
• Cryptology
• Cryptanalysis