Which is the cipher type in which letters are rearranged according to a regular system?

Which is the cipher type in which letters are rearranged according to a regular system?

• A. Substitution cipher
• B. Transposition cipher
• C. DES
• D. AES

Answer: (B)

Rearranging letters according to a regular system is a transposition cipher idea. In this type of cipher, the actual letters stay the same, but their positions are permuted following a fixed rule or pattern. For example, you might arrange the plaintext in a grid and read it out by columns or rows in a different order, so the letters appear in a new sequence without being altered themselves. This contrasts with substitution ciphers, where each letter is replaced by a different symbol or letter, changing the characters themselves. Modern algorithms like DES and AES aren’t simply rearranging letters; they perform complex sequences of substitutions and permutations at the bit or byte level.

Rearranging letters according to a regular system is a transposition cipher idea. In this type of cipher, the actual letters stay the same, but their positions are permuted following a fixed rule or pattern. For example, you might arrange the plaintext in a grid and read it out by columns or rows in a different order, so the letters appear in a new sequence without being altered themselves. This contrasts with substitution ciphers, where each letter is replaced by a different symbol or letter, changing the characters themselves. Modern algorithms like DES and AES aren’t simply rearranging letters; they perform complex sequences of substitutions and permutations at the bit or byte level.