Training & Professional Development

Advanced Encryption Standard (AES)

Uses Rijndael block cipher, specifies three key sizes; 128, 192 or 256 bit. Choice of key determines encryption level. AES is the government standard for encrypting SBU information. Best suited for hardware encryption.

The number of rounds of transformation is a function of the key size used

256 bit – 14 rounds.

192 bit – 12 rounds.

128 bit – 10 rounds.

Symmetric Algorithms that provide bulk (data) Encryption services only

DES and 3DES

TwoFish

128-bit blocks in 16 rounds. Key lengths can be up to 256 bits.

BlowFish

A block cipher operating on 64-bit blocks with a key length of up to 448 bits. The blocks go through 16 rounds of crypto functions.

IDEA

Ideas stand for International Data Encryption Algorithm. It operates on 64-bit blocks and uses a 128-bit key. (cont)

Symmetric Algorithms that provide bulk (data) Encryption services only

IDEA (cont)

Performs 8 rounds on 16-bit sub-blocks. Each 64-bit block is divided into 16 smaller blocks and each block has 8 rounds of mathematical functions performed on it.

IDEA is harder to crack than DES for the same key size and is used in PGP.

RC5

Block cipher of the variable block length. Key can be 0-2048 bits, blocks can be 32, 64 or 128 bits and the number of rounds can be 0 – 255. Created by Ron Rivest and patented by RSA data.

Asymmetric Encryption Algorithms – Authentication and Public Key Crypto

RSA

Defacto standard for public encryption. Invented by Ron Rivest, Adi Shamir, and Leonard Adleman. Developed at MIT. Security comes from the difficulty of factoring large numbers. Public and private key are functions of a pair of large prime numbers. RSA is used in many web browsers with SSL.

El-Gamal

Extends Diffie-Hellman to apply to encryption to digital signatures. Based on calculating discrete logarithms in a finite field.

Elliptical Curve Cryptosystem (ECC)

Provides much of the same functionality as RSA Digital signatures, secure key distribution, and encryption. ECC is very resource efficient – ideal for smaller devices. ECC providers higher protection with smaller keys than RSA. An ECC key of 160 bits is equivalent to a 1024-bit RSA key.