CSIT 311 COMPUTER NETWORK AND SECURITY ASSIGNMENT 2

DIFFERENCE BETWEEN

SYMMETRIC AND ASYMMETRIC ENCRYPTION SYSTEM

ADVANTAGES AND DISADVANTAGES

DIFFERENCE BETWEEN SYMMETRIC AND ASYMMETRIC ENCRYPTION SYSTEM

The most important difference between symmetric and asymmetric encryption system is that symmetric encryption uses the same key for encrypting and decrypting, while asymmetric encryption uses different keys. Asymmetric encryption uses two different keys, one key to encrypt and a different key to decrypt. A public key is used to encrypt and a non public private key is used to decrypt. Speed is a major disadvantage of Asymmetric encryption. Asymmetric encryption allows for non-repudiation and a methodology to securely exchange keys. Symmetric encryption is fast and efficient but uses as single key to encrypt and decrypt. The sender and receiver exchanging message must each have this single key. Distribution of this single symmetric key in a secure manner is required and is considered a disadvantage. Symmetric encryption does not provide for non-repudiation. The issue with asymmetric is that it is about 1000 times slower than symmetric encryption which makes it impractical when trying to encrypt large amounts of data.

Advantages of symmetric Encryption System

– High rates of data throughput

– Keys for symmetric-key ciphers are relatively short

– Symmetric-key ciphers can be composed to produce stronger ciphers

Disadvantages of symmetric Encryption System

– Key must remain secret at both ends

– In large networks, there are many keys pairs to be managed

– Sound cryptographic practices dictates that the key be changed frequently

Advantages of asymmetric Encryption System

– Only the private key must be kept secret

– In a large network the number of keys necessary may be considerably smaller than in the symmetric-key scenario

– There are many relatively efficient digital signature mechanisms as a result of asymmetric-key schemes

Disadvantages of asymmetric Encryption System

– Slower throughput rates than the best known symmetric-key schemes

– Large key size

– No asymmetric-key scheme has been proven to be secure

REFERENCES

http://cairnarvon.rotahall.org/2007/12/02/symmetric-and-asymmetric-encryption/

http://studentweb.tulane.edu/~mpoulos/CPST_492/ch4_assignment.doc

http://wiki.answers.com/Q/Difference_between_symmetric_and_asymmetric_key_cryptography

http://www.isecure-e.com/CryptoI/Lecture%205.ppt