Secret writings have been found in many civilizations dating back to thousands of years where wide spread writings were adopted. Some of these civilizations included the Egyptians with their use of hieroglyphics, the Greeks and Spartan and the use of Scytale, and the Romans with the use of the Caesar Cipher. All these encryption methods could be thought of as symmetric encryption, which uses the same key to encrypt and decrypt the ciphertext. With a more contemporary look at symmetric key encryption with computer data, we can classify it into two categories called block ciphers and stream ciphers. The data in a block cipher would be broken down into specific sizes, for example 64-bit blocks or 128-bit blocks, which then the blocks would be encrypted separately. In stream ciphers, data would be encrypted in a stream of bits as oppose to dividing the data into ...view middle of the document...
Unlike symmetric encryption, which is considered to be a very efficient, asymmetric tends to be very resource intensive because it takes a substantial amount of processing power to encrypt and decrypt data. Although asymmetric cryptography is considered inefficient when dealing with large amounts of information, it could be used for non-repudiation so that it would prevent a party from denying an action. Non-repudiation or identity authentication was not built into the symmetric encryption technology, therefor it is vulnerable to modification of data if the key falls into the wrong hands. Asymmetric cryptography does solve an immense problem with symmetric cryptography in that transmitting or exchanging the cryptographic keys are no longer necessary. Key management plays a vital role in all of cryptosystems. According to Martin (2012), “Without secure procedures for the handling of cryptographic keys throughout their lifecycle, the benefits of the use of strong cryptographic primitives are potentially lost” (p. 326).
Protocols with Asymmetric Cryptography
Some of the protocols used today that uses asymmetric cryptography include Secure Sockets Layer or SSL and Transport Layer Security or TLS. SSL is mainly used to encrypt internet traffic, is a certificate-based authentication, and uses both symmetric and asymmetric encryption during a session. In both of these protocols, asymmetric encryption is use to share the symmetric key, which is then used to encrypt the session data. TLS was created as a replacement to SSL and is used in many applications such as HTTPS for encryption (Gibson, 2011). Another popular standard used to digitally sign and encrypt email is Secure/Multipurpose Internet Mail Extension or S/MIME, which uses RSA for asymmetric encryption and AES for symmetric encryption (Gibson).
Gibson, D. (2011). CompTIA Security+: Get Certified Get Ahead SYO-301 Study Guide. North Charleston, SC: CreateSpace.
Martin, K. (2012). Everyday Cryptography: Fundamental Principles & Applications. Oxford, NY: Oxford University Press Inc.