DES, IDEA, RC4, AES)

Hashing for integrity (MD4, MD5, RIPEMD, SHA-1, SHA-2)

Asymmetric for authentication (RSA, El Gamal, ECC elliptic curve crypto)

Non-Repudiation is Asymmetric plus Hashing – condition where a message is a hash encrypted with the sender’s private key

Relationship of Encryption to Incidents and Threats

Elements needed for Encryption and Encryption Methods

Symmetric Encryption Systems

DES (Data Encryption Standard)

DES is a block encryption algorithm using 64-bit blocks. It uses a 64 bit key 56 bits of true key and 8 for parity. Characters are put through 16 rounds of transposition and substitution.

Devised in 1972 as a derivation of the “Lucifer” system

DES Describes the DEA (Data Encryption Algorithm)

FIPS PUB 46-1 (1977) and ANSI X3.92 (1981)

64bit blocks, 56-bit key and

16 rounds of transformation

Uses confusion and diffusion for encrypting plain text.

Confusion Conceals statistical connection between ciphertext and plaintext. Uses non-linear substitution boxes (S-Boxes)

Diffusion Spreads the influence of a plain text character over many ciphertext characters.

DES has 4 distinct modes of operation

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