The first communication system has a first security layer and a second security layer.

At least one transparent first base layer is arranged between the scrapeable security layer and the confidential information, said base layer remaining over the confidential information when the security layer is scraped off.

The security layer (101) and the firing layer (102) are penetrable by projectiles.

If a security layer is in effect and a subsequent SASL negotiation selects no security layer, the original security layer remains in effect.

In this manner, a fluid security layer may be provided.

The second security layer comprises system keys for secure communication between the hardware security modules.

If a security layer is in effect and a subsequent SASL negotiation selects a second security layer, then the second security layer replaces the first.

If a security layer is in effect and a subsequent SASL negotiation selects a second security layer, then the second security layer replaces the first.

If a security layer is in effect and a subsequent SASL negotiation selects no security layer, the original security layer remains in effect.

If a security layer is in effect and a subsequent SASL negotiation selects a second security layer, then the second security layer replaces the first.

The security layer (101) is made of a first material and the firing layer (102) is made of a second material.

As specified in [RFC4422], a newly negotiated SASL security layer replaces the installed SASL security layer.

A security layer is provided in the tunneling protocol layer of the wireless network, and a secured data packet is generated by adding to the data packet a header in accordance with said security layer of the tunneling protocol.

It’s an additional layer of security, not the only layer.

At least one of the opacifying layers (23) includes an embedded security device (25) such that removal of the security device (25) causes removal of the opacifying layer (23) to reveal the coloured security layer (22).