Phantom Touch

Phantom touch is a secret form of communication used by members of Libertas to send messages to each other. It is designed to be invisible and nearly impossible to detect, working via fingertip presses that transmit sensory stimuli to specific Libertas members via the Crimson Layer.

How it works

As part of a new Libertas member's initiation, the person gets a tattoo placed somewhere on their body (usually on their hand or forearm) in special invisible ink. This tattoo enables them to send messages via Crimson Layer manipulation, which allows them to generate and pick up sensory stimuli that can be detected by other tattoos. The higher the member's rank, the more complex the tattoo.
What makes the messages different from the sensory stimuli that can be detected by regular Variant tech is that they are sent via artificial mini-Shimmers, partially opened Rifts that are designed to go to different places in Aurora instead of Earth. The tattoo ink is actually designed to generate these Shimmers at will, keep them linked to the tattoo's owner at all times and enable them to control which tattoo the message will be transmitted to. This is top-secret Libertas technology that not even the Scholars know about.
The Libertas member starts the message by tracing the tattoo of the member they want to send a message to over their own. Once they feel a slight vibration in their skin, they'll know they've drawn a valid pattern and the Shimmer has opened. They will then place two or three fingertips on the tattoo and push them down in a pattern. This is based on pressure, so the message will be communicated via a series of soft, medium and hard presses.
Once the message is complete the Libertas member wipes one fingertip across the tattoo. This signals the end of the message and sends it via the Shimmer.
The message then comes through the recipient's Shimmer in the form of sensory stimuli that is felt directly on their skin (hence the name "phantom touch"). It is preceded by a series of five "buzzes" and the sensation of the sender's tattoo being traced over their own. This is an indication of who the message is from and a signal to the recipient to pay close attention (though more practiced users of phantom touch are able to understand the message immediately even while engaged in other tasks). At the end of the message, they feel the "wipe" that indicates the message is done.

Variations

Sometimes a message will need to be sent to multiple people at once. In this case, the sender will continue tracing the tattoos associated with each recipient until all of them have been drawn prior to sending the message. If an entire rank or group needs to be contacted, the sender will trace a symbol that represents that rank or group instead. If there are multiple ranks or groups that need to be contacted, the sender traces all of their symbols, just like when contacting multiple people. There is also a special symbol for sending a message to all members of Libertas at once.
If there are certain individuals that need to be excluded from a mass message, the sender can do so by tracing the rank/group symbol(s), pressing down hard for five seconds, then tracing the tattoos of those they wish to exclude before pressing down hard for another five seconds. They can then proceed with the message as normal.

Portal technology

The technology behind sending messages to multiple people at once via a single Shimmer is highly classified even within Libertas itself. The majority of Libertas' members are unaware of how it works or who was involved in creating it. Some speculate that it emerged as a result of attempts to create portals to worlds other than Earth, in order to find a new home for the Variants (or even just Libertas) and abandon Simone.