IPSec encryption algorithms listed in the material include which of the following?

• A. DES, 3DES, Blowfish, and AES
• B. RSA, DES, AES, MD5
• C. RSA, Blowfish, AES, RC4
• D. DES, RC4, MD5, RSA

Answer: (A)

IPSec confidentiality is provided by symmetric ciphers used by ESP to encrypt the payload. The encryption options listed—DES, 3DES, Blowfish, and AES—are all symmetric block ciphers that IPSec can use to scramble data with a shared key, offering confidentiality for the transmitted packets. DES is the older standard, 3DES strengthens DES by applying the algorithm three times, Blowfish offers a fast alternative with a different design, and AES is the widely adopted, strong modern choice. Other items in the mix aren’t encryption algorithms for IPSec data: RSA is an asymmetric algorithm used for key exchange or signatures, MD5 is a hashing function, and RC4 is a stream cipher that isn’t the set described for IPSec encryption in the material. Therefore, the four listed symmetric encryption algorithms are the ones IPSec typically references for payload encryption.