SAM ceiling and receiling parameters

You are here:

SAM ceiling and receiling parameters

SAM ceiling

Each SAM key has a ceiling and a counter. The ceiling of the key defines the number of times the SAM can execute the key action. The counter of the key counts the number of executed actions. When the counter reaches the ceiling, the SAM can no longer execute the action defined by the SAM key.

Example

The SAM key for the validation of contracts has a ceiling of 3000. If the ceiling of 3000 is reached, the SAM key is deactivated and can no longer validate contracts.

Receiling parameters

Besides a ceiling and a counter, the SAM key also has a set of receiling parameters. These parameters allow to raise the ceiling of the key when the ceiling is almost reached, so the SAM key is not deactivated and the SAM can keep executing the key action.

The raising of the ceiling is controlled by the following three parameters:

Parameter	Description
Receiling threshold	Indicates how close the counter has to get to the ceiling, before the ceiling can be raised. Example The threshold is set to 100. The ceiling can only be raised when the counter is less than 100 actions away from the ceiling.
Receiling number	Indicates how much the ceiling has to be raised when the SAM key is receiled. At each receiling, the receiling number is added to the current number of actions in the counter. Example The receiling number is set to 3000. At a receiling, the current number of actions (number in the counter) is raised with 3000. When a SAM is taken into use for the first time, his initial ceiling is set to the receiling number.
Receiling limit	The absolute amount of actions that can be executed with the SAM key. If the counter reaches this limit, the ceiling can no longer be raised.

Parameter

Description

Receiling threshold

Indicates how close the counter has to get to the ceiling, before the ceiling can be raised.

Example

The threshold is set to 100. The ceiling can only be raised when the counter is less than 100 actions away from the ceiling.

Receiling number

Indicates how much the ceiling has to be raised when the SAM key is receiled. At each receiling, the receiling number is added to the current number of actions in the counter.

Example

The receiling number is set to 3000. At a receiling, the current number of actions (number in the counter) is raised with 3000.

When a SAM is taken into use for the first time, his initial ceiling is set to the receiling number.

Receiling limit

The absolute amount of actions that can be executed with the SAM key. If the counter reaches this limit, the ceiling can no longer be raised.

Receiling example

The SAM key for the loading of contracts onto smart cards has a receiling threshold of 20 and a receiling number of 100. The receiling of this SAM key will work as follows:

The SAM is taken into use and sends a heartbeat to mobi.guider.

mobi.guider sends the correct parameters to the SAM and the ceiling for the key is set to 100.

After six hours, the SAM sends a new heartbeat to mobi.guider. The SAM has loaded 45 contracts.

The SAM key is not receiled, because the threshold value is not reached yet (counter is more than 20 actions away from the ceiling).

After another six hours, the SAM sends a new heartbeat to mobi.guider. The SAM has loaded 87 contracts.

The SAM key is receiled, because the threshold value is reached (counter is less than 20 actions away from the ceiling). The new ceiling is set to 187.

Purpose

SAM keys get a ceiling to prevent fraud. The receiling mechanism is used to make sure you can keep using the SAM is case nothing suspicious is going on with the SAM.

Example

A SAM is stolen and could be used to make false cards. The receiling mechanism can then be deactivated, so the SAM can no longer be used once the ceiling is reached.