Which statement about RC4, RC5, and RC6 is accurate?

Which statement about RC4, RC5, and RC6 is accurate?

• A. Are all block ciphers that operate on fixed blocks
• B. Developed by RSA Security as symmetric encryption algorithms
• C. Are asymmetric algorithms used for key exchange
• D. Are deprecated due to security flaws

Answer: (B)

The fundamental point is that these ciphers were designed by RSA Security as symmetric encryption algorithms, meaning the same key is used to both encrypt and decrypt. RC4 is a stream cipher, while RC5 and RC6 are block ciphers, but all three are tied to RSA Security and share the private-key approach for confidentiality. The other statements don’t fit: RC4 isn’t a block cipher, so calling all of them block ciphers is inaccurate; they are not asymmetric algorithms used for key exchange; and while RC4 is considered deprecated due to vulnerabilities, that blanket claim doesn’t apply to RC5 and RC6, which aren’t universally deprecated.

The fundamental point is that these ciphers were designed by RSA Security as symmetric encryption algorithms, meaning the same key is used to both encrypt and decrypt. RC4 is a stream cipher, while RC5 and RC6 are block ciphers, but all three are tied to RSA Security and share the private-key approach for confidentiality. The other statements don’t fit: RC4 isn’t a block cipher, so calling all of them block ciphers is inaccurate; they are not asymmetric algorithms used for key exchange; and while RC4 is considered deprecated due to vulnerabilities, that blanket claim doesn’t apply to RC5 and RC6, which aren’t universally deprecated.