Quizz #2 Flashcards
Clipper chip
Encryption chip that government place in every American-made device that have a computer or computer component
ESS
Escrow Encryption Standard
How many key a clipper chip has
each hip has a unit key used to encrypt a copy of each’s user’s session key not the message
LEAF
Law Enforcement Access Field - value included in the chip and sent out
Key escrow
For check and balance purpose, the encryption key is split into two sections and given to two escrows agencies.
how many entities are involved with decryption for check and balance purpose
3 of them : 2 agencies and a law enforcement representative.
Main key pieces to encryption
Algorithms and the keys
what is a key
A string of random bits that will be inserted into the algorithm
Keys used by cryptography algorithm
***Symmetric keys called secret keys ***Asymmetric Keys called public keys
Symmetric or secret Key
Both parties will be using the same key for encryption and decryption. It’s a dual functionality. EACH communication has its own key that is used by a sender and the receiver.
Symmetric formula
n(n-1)/2
What is the security of Symmetric encryption
How well users protect the key.
what does symmetric cryptosystem provides
confidentiality only.They cannot provide authentication or nonrepudation
Example of symmetric key cryptography
***Data encryption Standard (DES) *** Triple DED (3DES) *** Blowfish *** IDEA *** RC4, RC5, RC6
Asymmetric
Each entity has different keys. Two keys are required ( with one to encrypt it, and the second to decrypt).
How are the two asymmetric keys made up?
One public Key and one private key. Both keys are mathematically related, but cannot be derived from each other.
What does Asymmetric cryptosystem provides
authenticity
Secure message format
Check for confidentiality - The sender would encrypt the file with the receiver’s public to make sure that only the receiver’s private key is use to decrypt it.
open message format
Check for authenticity - The sender encrypts the message with her own private key
secured and signed format
Sender encrypts message with her private key, and then encrypt it again with the receiver’s public key. This provides confidentiality and authenticity.
Example of asymmetric key algorithm
*** RsA *** Elliptic Curve Cryptosystem (ECC) *** Diffie-Hellman *** El Gamal *** Digital Signature System (DSS)
Main Type of symmetric algorithm
Block cipher and stream cipher
Block Ciphers
When used for encryption and decryption purpose, the message is divided into blocks of bit. Block Ciphers use diffusion and confusion in their methods.
Stream Ciphers
Treats the message as a stream of bits or bytes and performs mathematical functions on them individually
Where at stream and block ciphers suitable for implementation
** Stream is suitable for hardware **Block is suitable for software
Lucifer
Is a Data Encryption Standard (DES) developed by IBM.. DES is a symmetric system DES is a block encryption algorithm
Mode of operation of DES
*** Electronic Code Book Mode (ECB) - a 64 bit data block is entered into the algorithm with a key, and a block of ciphertext is produced. *** Cipher Block Chaining Mode (CBC) *** Cipher Feedback Mode - Ciphertext from the previous block of data is used in encrypting the next block of data. *** Output Feedback Mode -
XOR - Exclusive OR
Operation that is applied to two bits.
AES
Advanced Encryption standard - Symmetric block cipher algorithm.
Types of Asymmetric Encryption Algorithms
RSA - used for digital signatures and encryption. El Gamal - Public key that can be used for digital signatures and key exchanges ECC
