Methods and systems for account authentication in a distributed computing node group may involve sending a message to a member, the message having a first timestamp, increasing an authentication failure count, receiving a first key-exchange message from the member, the first key-exchange message having a second timestamp, evaluating the second timestamp, and determining whether to ignore the first key-exchange message based on an evaluation of the second timestamp. The first timestamp may be associated with a message received from the member prior to sending the message with the first timestamp to the member. The first key-exchange message may include a value computed by the member based on a group passcode shared with the member. The evaluation of the second timestamp may be based on at least one of a default value, the authentication failure count, or a timestamp associated with the group passcode.