Cryptography

Popular Symmetric Encryption Algorithms

Symmetric Encryption also known as private key encryption is a type of encryption that use the same secret key for both encryption and decryption. Both sides, the sender and the receiver must know the secret key so they can encrypt and decrypt the information.

Symmetric algorithms can be divided into stream algorithms and block algorithms.

Stream Algorithms (Stream Ciphers) operate directly on a stream of bytes and encrypt the bits of information one bit or 1 byte at a time. These algorithms are faster than block ciphers.

Block Algorithms (Block Ciphers) encrypt information by breaking it down in fixed-length groups-blocks of bits (usually 64 bits) and encrypting one block at a time. Block algorithms are most commonly used in the IT world today.

 

AES/Rijndael

Designers: Vincent Rijmen, Joan Daemen

Published: 1998

Key sizes: 128, 192 or 256 bits

Type: Block Cipher

Block sizes: 128 bits

Rounds: 10, 12, 14 (depending on key size)

 

Blowfish

Designers: Bruce Schneier

Published: 1993

Key sizes: 1–448 bits

Type: Block Cipher

Block sizes: 64 bits

Rounds: 16

 

CAST5

Designers:  Carlisle Adams, Stafford Tavares

Published: 1996

Key sizes: 40 to 128 bits

Type: Block Cipher

Block sizes: 64 bits

Rounds: 12 or 16

 

IDEA

Designers:  Xuejia Lai, James Massey

Published:

Key sizes: 128 bits

Type: Block Cipher

Block sizes: 64 bits

Rounds: 8.5

 

RC4

Designers:  Ron Rivest

Published: 1994 (designed in 1987)

Key sizes: 40–2,048 bits

Type: Stream Cipher

State size: 2,064 bits

Rounds: 256

 

Serpent

Designers:  Ross Anderson, Eli Biham, Lars Knudsen

Published: 1998

Key sizes: 128, 192 or 256 bits

Type: Block Cipher

Block sizes: 128 bits

Rounds: 32

 

Triple DES

Designers:

Published: 1998

Key sizes: 168, 112 or 56 bits

Type: Block Cipher

Block sizes: 64 bits

Rounds: 48

 

Twofish

Designers: Bruce Schneier

Published: 1998

Key sizes: 128, 192 or 256 bits

Type: Block Cipher

Block sizes: 128 bits

Rounds: 16