Methods and apparatus are provided for secure transmission of alert messages over a message locking channel. An alert message is transmitted from a Security Alerting System indicating a potential compromise of a protected resource by obtaining the alert message from the Security Alerting System; authenticating the alert message using a secret key known by a server, wherein the secret key evolves in a forward-secure manner; storing the authenticated alert message in a buffer; and transmitting the buffer to the server. The alert message is authenticated by digitally signing the alert message or applying a message authentication code and is possibly encrypted using a secret key known by a server, wherein the secret key evolves in a forward-secure manner. The authenticated alert message can be maintained in the buffer after the transmitting step. The buffer optionally has a fixed-size and alert messages can be stored in a round-robin manner, for example, from a random position. The buffer can be encrypted prior to transmission to the server.