Each tenant of a secure web gateway (SWG) is issued a secret key. A user accesses a unique secret key derived from the tenant's secret key and loads the secret key into an application which generates time-based one time passwords (TOTPs). When the SWG receives a connection request from a client and cannot decrypt the network traffic, the SWG challenges the client request and indicates an authentication scheme to be used. The client obtains user credentials, constructs a response to the challenge based on the authentication scheme, and issues a connection request to the SWG which indicates the response. The SWG determines an expected response based on a locally generated TOTP and the secret key of the corresponding tenant. If the expected response matches the provided response, the SWG authenticates the user, allows the connection request, and whitelists the client for a period longer than the lifetime of the TOTP.