Public Key Infrastructure (PKI) uses asymmetric key encryption between parties. The originator encrypts information using the intended recipient's "public" key in order to get confidentiality of the…

Question

Options

• AThe sender and recipient have reached a mutual agreement on the encryption key exchange
• BThe channels through which the information flows are secure.
• CThe recipient's identity can be positively verified by the sender.
• DThe sender of the message is the only other person with access to the recipient's private key.

• A
  5% (3)
• B
  2% (1)
• C
  92% (56)
• D
  2% (1)

Explanation

PKI's "Infrastructure" refers to the Certificate Authority (CA) system - a trusted third party that issues and signs digital certificates binding a public key to a verified identity, which is exactly what allows the sender to positively confirm who owns the public key they're using to encrypt. Without this identity verification layer, anyone could hand you a public key and claim to be someone they're not (a man-in-the-middle attack).

Why the distractors are wrong:

• A is wrong because asymmetric encryption requires no prior key agreement - that's the whole point; you simply use the recipient's published public key.
• B is wrong because PKI secures the data, not the channel; the information can travel over insecure networks and still be protected.
• D is wrong and dangerous - the private key is never shared with anyone, including the sender; only the recipient holds it.

Memory tip: Think of PKI's "Infrastructure" as a passport office. Encryption is the lock-and-key mechanism, but the infrastructure is the government agency that vouches for your identity. When someone hands you their public key with a CA-signed certificate, it's like showing a passport - you can trust who they are, not just that the lock works.

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