From OST

Public Key vs. PrivateKey Encryption

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**Public Key**There are numerous different types of cryptography in the world of Network security and the one that I am researching is Public-Key Cryptography. In the fast paced and always changing world of network security this is a highly used form of cryptography. Rothman (1999) stated, “Public-key cryptography is becoming the cornerstone for many large corporations and companies”. Now public-key is very similar to private-key except with public-key you don’t have to share keys. Public-key cryptography was first introduced to network security by Whitefield Diffie and martin Hellman in their publication called New Directions in cryptography (Dyson 1999). There are a lot of crptography methods and styles, but the one thing that sets public-key apart from the others is the asymmetric key algorithms.

**Private Key**This type of security uses symmetric key algorithms. Now what this means is that the sender and receiver have the same key and this type of encryption has been used for many thousands of years.

**Asymmetric Key Style**Now what the asymmetric key style means is that the key that encrypts the message is not the same that decrypts it and this makes it very secure. Chris Woodward (2008) said “how public key encryption works is that each user or person has two keys one that is public and one that must be kept secret, and that way any one can send you an encrypted message with the public key, but only you can decrypt it with the secret key and read the message. Public key is based on the idea of a trap door effect. There is one more area to the public-key encryption and that is digital signatures. Digital signatures works the same way but it digitally verifies the public and secret key. Now through my research the only real problem there is with public key encryption is the trust issue that the public key is correct, belongs to the correct person or if it’s been forged.

**Real World**I have researched and found out that a lot of banks, credit card companies, and other financial institutions are some of the main users of the public-key system. They have used it for some time now and it’s a very good system for them. Private Key encryption is also known as symmetric encryption uses the same to encrypt and decrypt the information. This kind of cryptography is simple compared to others. When a secret message is sent from a sender to the recipient they both have to have a copy of the secret key for the information to get to the intended party. In 1940 the Shannon theory proved that you must use a key as long as the information that you are sending for this to be totally encrypted. This type of encryption is widely used to encrypt data on hard drives. The most popular and widely used form of this style of encryption is DES (Data Encryption Standard). The strength of the secret key is the strength and the style of the algorithm that is used to design the encryption or secret key.

References

Rothman, Mike (1999) Public Key Encryption for Dummies, NetworkWorld.com

Woodward, Chris (2008) Encryption, www.expalinthatstuff.com

Kayne, R (2009) What is Public-key Encryption, www.wisegeek.com

Sheldon, T (2001) Secret Key Cryptography, www.linktionary.com/s/secret_key.html