Jane, a VPN administrator, was asked to implement an encryption cipher with a MINIMUM effective security of 128-bits. Which of the following should Jane select for the tunnel encryption?

Question

Options

• ABlowfish
• BDES
• CSHA256
• DHMAC

• A
  73% (19)
• B
  4% (1)
• C
  15% (4)
• D
  8% (2)

Explanation

Blowfish supports variable key lengths from 32 to 448 bits, meaning it can be configured to meet or exceed 128-bit effective security. It is a legitimate symmetric block cipher suitable for VPN tunnel encryption. DES (Option B) has only a 56-bit key length, which falls far below the 128-bit minimum requirement and is considered cryptographically broken. SHA-256 (Option C) is a cryptographic hash function used for integrity verification and digital signatures - it is not an encryption cipher and cannot encrypt tunnel traffic. HMAC (Option D) is a Hash-based Message Authentication Code used to verify message integrity and authenticity - again, it is not an encryption cipher and cannot fulfill the tunnel encryption role. Blowfish is the only listed option that is both an encryption cipher and capable of 128-bit or higher security.

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