From the course: Ethical Hacking: Cryptography
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Common symmetric algorithms
From the course: Ethical Hacking: Cryptography
Common symmetric algorithms
- [Instructor] There are six common symmetric algorithms, DES, 3DES, AES, along with the family of ciphers designed by Ron Rivest called RC4, RC5, and RC6. If you recall from our earlier review, these six can be further categorized as stream based, or block-based ciphers. Let's look at each algorithm to better understand their properties and differentiators. DES stands for Data Encryption Standard. It was introduced in 1975 as the first symmetric block-based algorithm. It went on to become a national standard in 1977. DES encrypts a 64-bit block of data using a 56-bit key. That might sound a bit confusing to use a 64-bit encryption that has the effectiveness of 56 bits. Let me explain. Of those 64 bits, only 56 actually contain keying information. The remaining eight bits are supposed to contain parity information to ensure that the other 56 bits are accurate. Think of a parity bit as a check bit for finding errors or defects. The irony is the parity bits are rarely used. What you…
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