Response wrapping is a feature that allows Vault to take the response it would have sent to a client and instead insert it into the cubbyhole of a single-use token, returning that token instead. The client can then unwrap the token and retrieve the original response. Response wrapping has several benefits, such as providing cover, malfeasance detection, and lifetime limitation for the secret data. One of the benefits is to ensure that only a single party can ever unwrap the token and see what’s inside, as the token can be used only once and cannot be unwrapped by anyone else, even the root user or the creator of the token. This provides a way to securely distribute secrets to the intended recipients and detect any tampering or interception along the way5.
The other options are not benefits of response wrapping:
Log every use of a secret: Response wrapping does not log every use of a secret, as the secret is not directly exposed to the client or the network. However, Vault does log the creation and deletion of the response-wrapping token, and the client can use the audit device to log the unwrapping operation6.
Load balance secret generation across a Vault cluster: Response wrapping does not load balance secret generation across a Vault cluster, as the secret is generated by the Vault server that receives the request and the response-wrapping token is bound to that server. However, Vault does support high availability and replication modes that can distribute the load and improve the performance of the cluster7.
Provide error recovery to a secret so it is not corrupted in transit: Response wrapping does not provide error recovery to a secret so it is not corrupted in transit, as the secret is encrypted and stored in the cubbyhole of the token and cannot be modified or corrupted by anyone. However, if the token is lost or expired, the secret cannot be recovered either, so the client should have a backup or retry mechanism to handle such cases.
References: 5(https://developer.hashicorp.com/vault/docs/concepts/response-wrapping), 6(https://developer.hashicorp.com/vault/docs/secrets), 7(https://developer.hashicorp.com/vault/docs/secrets), (https://developer.hashicorp.com/vault/tutorials/secrets-management/cubbyhole-response-wrapping)
