block cipher

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Last updated

June 22, 2026

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A block cipher is a type of cryptographic system that encrypts data in fixed-size chunks, or blocks. Unlike stream ciphers that encrypt data character by character, block ciphers process entire blocks of plaintext at once using a common secret key. The size of these blocks can vary; for instance, the Data Encryption Standard (DES) uses a block size of 64 bits. This method ensures that the same plaintext block will always result in the same ciphertext block when encrypted with the same key.12

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cryptology
Block and stream ciphers
In general, cipher systems transform fixed-size pieces of plaintext into ciphertext. In older manual systems these pieces were usually single letters or characters—or occasionally, as in the Playfair cipher, digraphs, since this was as large a unit as could feasibly be…
Read More
In general, cipher systems transform fixed-size pieces of plaintext into ciphertext. In older manual systems these pieces were usually single letters or characters—or occasionally, as in the Playfair cipher, digraphs, since this was as large a unit as could feasibly be…
Read More