What is Symmetric Cryptography
Today we will be looking at some bullet points of Symmetric Cryptography. I have already surpassed this section in my reading material but wanted to include this information in a post. Don’t you feel special? As always, please feel free to comment. I would love to discuss and learn with others that are preparing for this exam.
Symmetric Cryptography
This type of cryptography uses algorithms that encrypt data with one key and decrypt data with the same key. The keys are the same.
Synonyms
Secret Keys
Shared Secret
Strengths
Much faster than Asymmetric Cryptography - The speed at which you can encrypt and decrypt data using a Symmetric algorithm is much faster than that of Asymmetric algorithms. The Symmetric mathematical functions are much less intense. However, that doesn’t mean they are less secure.
If a large key size is used then the cryptography is hard to break (impossible? nearly impossible?)
Weaknesses
Key delivery - The resulting cipher text that is encrypted using a symmetric algorithm key can be decrypted using the same symmetric key. You need a key for each individual you are communicating with. This makes key management and key delivery overwhelming. Here is a formula to calculate how many keys you will need N(N-1)/2 = Keys. So, if you have 5 people all communicating with each other then you will need 5(4)/2 = 10 keys.
Does not provide authenticity or non-repudiation because multiple people have the same key.
Examples of Symmetric Algorithms
Data Encryption Standard (DES) (Note: This “standard” uses the DEA - Data Encryption Algorithm)
Triple-DES (3DES)
Blowfish
International Data Encryption Algorithm (IDEA)
RC4, RC5, and RC6
Advanced Encryption Standard (AES)