Flashcards
Encryption
Cards in this deck (7)
- 1What is Symmetric encryption?Symmetric encryption is the oldest and best-known technique. A secret key, which can be a number, a word, or just a string of random letters, is applied to the text of a message to change the content in a particular way. This might be as simple as shifting each letter by a number of places in the alphabet
- 2List some features of symmetric encryption.– Also known as Shared or Secret Key Encryption
– Uses a shared secret key Ks to encrypt a message, M.
If Ciphertext = Ks(M)
Then M = Ks(Ciphertext)
– Requires a key distribution service - The Trusted Third Party
– Example is Data Encryption Standard (DES), developed for US DoD. - 3Why Use Symmetrical Encryption– Typically faster 100 to 1,000 times than public key encryption, places a much heavier computational load on computer processors than symmetric key encryption.
– Symmetric key technology is generally used to provide secrecy for the bulk encryption and decryption of information.
– Symmetric keys are commonly used by security protocols as session keys for confidential online communications. - 4List further reasons why Symmetrical Encryption used...– Transport Layer Security (TLS) and Internet Protocol security (IPSec) protocols use symmetric session keys with standard encryption algorithms to encrypt and decrypt confidential communications between parties.
– Different session keys are used for each confidential communication session and session keys are sometimes renewed at specified intervals. - 5What is Asymmetric Encryption.Asymmetric cryptography or public-key cryptography is cryptography in which a pair of keys is used to encrypt and decrypt a message so that it arrives securely. Initially, a network user receives a public and private key pair from a certificate authority.
- 6How does Asymmetric encryption work?– Asymmetric Uses a key-pair - two different keys:
one private, Kpriv - for decryption
one public, Kpub - for encryptionM = Kpriv( Kpub(M)) - 7List some features of Asymmetric Encryption.– Key pairs based on factors of prime numbers
– Difficult to calculate effective key pairs
– Extremely difficult to crack (billions of years)
– Slower in operation than DES (100-10,000 times)
– Provides a signature that cannot be reproduced
– Keys for commercial level security are 1024 bits long and are typically 1024–2048 bits long
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- Networking Flashcards on Encryption, created by adamelvin786 on 20/01/2015.
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- adamelvin786
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