There are several types of devices that can distinguish the characteristic shape of a key. The so-called “English”, “Finnish” and cross code cylinders (Fig. 3, position 2, 3 and 4) used a long time and are quite common. Their disadvantage is the low level of secrecy: sometimes similar lock can be opened by simply picking up like a key. Modern cylinders of “Euro profile (Fig. 3, position 1), by contrast, have increased privacy. On a flat surface the keys to this type of locks are dotted grooves.
Reliability is determined by the lock their number: it should be no less than five. Forge or pick up a key is almost impossible. Many manufacturers use in their products with more secrets and special technical solutions that make it difficult the use of master keys. To open a high-quality cylinder lock mid-level of secrecy, even the experienced thief will take at least an hour. It is unlikely that so long “racket” might go unnoticed.
And some models impossible to “cheat” in principle. In addition, the design of modern cylinder locks of the leading manufacturers (EVVA, Mul-t-lock, cisa, etc.) provides protection against knock-cylinder, breaking the “turn” (when the with a sledgehammer hammer hardened steel plate and the lever sharply crank it, breaking the lock) and “Bumping” (unlock code mechanism for tapping on the key). The main use of three or Four-lock, providing locking doors in several directions (up, down, and loop of the frame). And in the lock part, he should have at least three broad bolts (locking rod) from the stable alloy.