Chaincode Development, Deployment, and Lifecycle Management BDC Practice Questions (Page 4)

Questions 16–20

1. 16foundation · easy

   In Hyperledger Fabric, how is a chaincode upgrade typically performed?

   • ABy modifying the existing chaincode source and restarting the peer
   • BBy using the 'upgrade' command on the ordering service
   • CBy installing a new package with a new version and committing a new chaincode definition
   • DBy deleting the old chaincode and reinstalling the same version
   Reveal Solution Discussion Select an answer first
2. 17application · medium

   A chaincode developer is writing a function that updates a user's profile. The function receives a user ID and new profile data. The chaincode must ensure that only the user themselves or an administrator can update the profile. The chaincode uses the Fabric Client Identity (CID) library. What is the most appropriate way to enforce this access control?

   • AUse cid.GetMSPID() to verify the caller is from the same organization as the user, and allow the update if they are.
   • BUse cid.GetAttributeValue() to retrieve a custom attribute like 'role' and allow if it equals 'admin'.
   • CUse the stub.GetCreator() function to get the certificate and check if it is valid.
   • DUse cid.GetID() to obtain the caller's identity and compare it to the user ID stored in the profile, or check if the caller's MSP role is 'admin'.
   Reveal Solution Discussion Select an answer first
4. 18application · medium

   A chaincode function allows users to transfer tokens. The developer wants to ensure that only the token owner can initiate a transfer. Which access control mechanism should be implemented inside the chaincode?

   • ARely on the peer's MSP to restrict which clients can invoke the chaincode.
   • BExtract the caller's certificate from the stub and compare its subject or attribute to the stored owner.
   • CStore the caller's password in the chaincode state and verify it on each invocation.
   • DUse the channel's ACL to define per-function access rules.
   Reveal Solution Discussion Select an answer first
5. 19application · medium

   A developer is writing chaincode that manages a list of authorized users. The list is stored as a single state key containing an array. The function to add a user reads the entire array, appends the new user, and writes it back. This function is called frequently and is slow. What is the best way to improve performance?

   • AStore each user as a separate state key with a composite key that includes the user ID.
   • BIncrease the transaction timeout to allow more time for the read-write operation.
   • CKeep the array in a global variable and update it in memory.
   • DUse a rich query to append to the array in the database.
   Reveal Solution Discussion Select an answer first
6. 20expert · hard

   A Hyperledger Fabric network has a chaincode that is used for asset trading. The endorsement policy is set to require signatures from two of the three organizations. A new organization joins the network and wants to participate in endorsing transactions. What must be done to allow the new organization to endorse?

   • AOnly install the chaincode on the new organization's peers; the endorsement policy will automatically include them.
   • BInstall the chaincode on the new organization's peers and update the endorsement policy to include the new organization.
   • CUpdate the endorsement policy to include the new organization, but do not install the chaincode on their peers.
   • DCreate a new channel that includes the new organization and move the chaincode to that channel.
   Reveal Solution Discussion Select an answer first