EVVA MCS

	EVVA MCS
	;
Name	EVVA MCS
Manufacturer	EVVA
Lock Type	Cylinder
Lock Design	Magnetic
Year(s) Produced	1975-Present
Patent	US 4,084,416

The MCS (or Magnetic Code System) is a magnetic lock made by EVVA. It is one of the few magnetic locks to gain widespread acceptance and is also considered one of the best mechanical locks in the world. The MCS has been sold under a variety of names, including IKON System M (DE) and Mottura MC (IT)^[1].

Principles of operation

Main Locking Element (Magnetic Rotors)

There are 8 magnetic rotors, 4 on each side of the keyway
Magnets in each rotor are Diametrically charged
A plate with one or more gates is glued to the magnet
Inner sidebar has 3 fingers and outer sidebar has 1 finger/pin that interact with the rotor gates
Whole sidebar must slide fore (towards key bow)
To align with milling in the bible
When both sidebars are slid forward the core can then rotate.

Minor Locking Elements (Generation 1)

Gen 1 locks have 1 active ball bearing pin, this simply must be depressed to allow the core to turn, there is only 1 height.
There are 12 passive ball bearings that will most often jam when an incorrect key is inserted. Occasionally these can also jam when under a picking attack, but they are less likely and need only a slight bump to be corrected.

Minor Locking Elements (Generation 2)

Gen 2 locks have the same active ball bearing pin, it is simply moved forward in the lock from Gen 1
Gen 2 adds passive sliders (4 on top, 3 on bottom)
Key has slider tracks on the top and bottom
If sliders are incorrect they will jam the core not allowing magnetic sidebar to be tested.
Once aligned core will rotate (until sidebar comes into play).
WARNING! Sliders can fall out of place once core is rotated if lock is more worn and a key is not in the lock.

Disassembly instructions

Generation 1 (1 active ball bearing, 12 passive ball bearings)

Remove c-clip
Depress active ball bearing with a tool and slide core towards front
Keep checking both ball bearing and gap towards the rear of plug as they will both get caught on the 3 passive pins and 1 active pin as plug moves forward
Once plug is out:
1. Remove split ring sidebar reset system
2. Remove outer sidebar
3. Use pliers or knife to snap out plastic sidebar spacer (WARNING! older locks the plastic can be quite brittle, likely it will crack, though cracked sidebar spacers can be repaired with superglue)
4. Remove inner sidebar to then access the rotors
5. Rotors can be removed
6. Repeat for other sidebar
Link to YouTube Video on Disassembly

Ratings

EN 1303:2015

Vulnerabilities

The MCS is considered one of the best mechanical locks in the world.

Confirmed picking and decoding are possible on this lock using an audio attack for feedback.

It is vulnerable to one or more of the following:

It is possible to decode this lock by moving the rotors individually to a known position and testing them against the 'fence'. Correct gates can be heard. A mems microphone is placed in the tip of the testing device. Rotors are manipulated via a transverse magnetic field. This tool was designed and made by Technical Entry in July 2016 (technicalentry.de). It works well but requires fine finger skills. Feedback is excellent. After the decoding procedure a MUK (make up key) is setup and the lock can be opened as necessary.