Hashing, Digital Signatures, and Certificates CASEJAVA Practice Questions (Page 6)

Questions 26–28

1. 26application · medium

   A Java application needs to sign a message so that the recipient can verify both the sender's identity and the message's integrity. The sender and recipient do not share a secret. Which JCA algorithm should the developer use?

   • ASHA256withRSA
   • BAES/GCM/NoPadding
   • CPBKDF2WithHmacSHA256
   • DHmacSHA256
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2. 27application · medium

   A Java application verifies a server certificate that is signed by an intermediate CA. The intermediate CA's certificate is signed by a root CA that is in the application's trust store. Which additional step is required for the verification to succeed?

   • AThe application must verify the root CA's certificate is not expired.
   • BThe application must ignore the intermediate and verify the leaf directly against the root.
   • CThe application must add the server's leaf certificate to its trust store.
   • DThe application must receive the intermediate CA certificate and build the chain to the root.
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3. 28application · medium

   A developer is implementing an API that receives webhook notifications. To verify that a notification genuinely originated from the vendor, the vendor provides a shared secret and expects the developer to compute a keyed hash over the raw request body. Which Java code snippet correctly implements this verification?

   • ASignature.getInstance("SHA256withRSA") with the vendor's public key
   • BCipher.getInstance("AES/GCM/NoPadding") with the shared secret as the key
   • CMessageDigest.getInstance("SHA-256").digest(body)
   • DMac.getInstance("HmacSHA256") initialized with the shared secret, then doFinal(body)
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