Enciphering techniques in which individual plaintext letters (or individual bits) change positions.
A cipher in which the plain text remains the same but the order of the characters is scrambled. Thus, the word "DOG" might become "OGD." Transposition is sometimes used as one step in the midst of several mathematical operations that, together, make up a cryptographic algorithm.
In classical cryptography, a transposition cipher changes one character from the plaintext to another (to decrypt the reverse is done). That is, the order of the characters is changed. Mathematically a bijective function is used on the characters' positions to encrypt and an inverse function to decrypt.