Rotor for a lock comprising (a) a stator with an open chamber with a longitudinal central axis, intended to receive said rotor, said rotor having an open chamber with a central axis in which is located an assembly comprising a series of locking discs intended to undergo at least one relative rotational movement with respect to the central axis of the open chamber of the rotor when inserting a locking key into an open central passage of the series of discs, said locking discs each having at least one finger or a protuberance directed towards the open central passage, the locking discs each having a circular locking surface with one or more peripheral notches, for which said key is a key for unlocking the rotor which comprises a substantially cylindrical rod or part of a rod with a central axis and having on its substantially cylindrical outer face at least two sinuous guiding grooves (10C, 10D) adapted to receive at least one finger or protuberance of locking tumblers or discs, and a free end with a guiding means for guiding each finger or protuberance in one of said at least two sinuous guiding grooves (10C, 10D), said substantially cylindrical rod further having a planar portion adapted to be inserted at least partially into the open central passage after the introduction of the free end into the open central passage of the series of locking tumblers or discs by translation in the direction of the central axis of the open chamber, wherein said rotor comprises at least two longitudinal slots each adapted to receive a latch pin movable between a first position in which the considered latch pin extends only partially in a longitudinal slot and partially outside said rotor out of the considered longitudinal slot, and a second position in which the considered latch pin extends only partially in a longitudinal slot and partially in the chamber of the rotor outside the considered longitudinal slot, the movement of each latch pin from its first position to its second position being effected by a rotational movement of the rotor when the latter is placed in a stator, for which the locking discs are each rotatably mounted in the open chamber of the rotor so that the translational movement of the unlocking key of the rotor in the direction of the central axis of the open chamber of the rotor rotates the locking discs between themselves and with respect to the rotor, so that, after one rotation of the discs between them, peripheral notches of the locking discs are aligned with each other to form at least one or two recesses suitable for receiving the latch pins, wherein each longitudinal slot extends between a first window (1D1) facing the open chamber of the rotor, and a second window (1D2) extending along the outer cylindrical face of the rotor, wherein the latch pins each have the shape of a cylindrical rod wit a diameter of 2 to 5mm made of steel; in which the rotor comprises at least one transmission disc of torque to the rotor during a rotation of the unlocking key, after introduction of the substantially cylindrical rod in the passage open central of the series of locking discs by translational movement of the rod of the unlocking key in the direction of the central axis of the open chamber of the rotor, said transmission disc having a central opening partially circular with a flat edge (8E1) adapted to at least partially match the flat part of the rod of the unlocking key after the introduction of the free end of the rod in the open central passage of the series of locking discs by translation in the direction of the central axis of the open chamber, said transmission disc having means (8D1) cooperating directly with an element of the rotor so that a rotation of the transmission disc causes a rotation of the rotor over a first angular sector of rotation, and wherein the locking discs are arranged in the open chamber of the rotor so as not to exert torque on the rotor at least during said first angular sector of rotation of the transmission disc, in which each longitudinal slot each adapted to receive a latch pin in the form of a cylindrical rod has or is associated with at least one means forming a stop for limiting the movement of the latch pin out of the slot through the second window (1D2), the second window (1D2) of each longitudinal slot advantageously having at least one or more open parts with a spacing less than the diameter of the cylindrical rod of the latch pin in which the second window (1D2) extends between two longitudinal edges spaced from each other by a spacing of between 0.5 and 0.95 times the diameter of the rod of the pin, while that the first window (1D1) extends between two longitudinal edges spaced from each other by a spacing between 1.1 and 3 times, preferably 1.2 to 2 times the diameter of the rod the pin, in which the longitudinal edges of the second window (1D2) of a longitudinal slot are located in an angular sector included in the radial extension of the angular sector of the longitudinal edges of the first window (1D1) of the considered longitudinal slot, and wherein the longitudinal edges of the first window (1D1) of a longitudinal slot are each connected to a longitudinal edge of the second window (1D2) by an at least partially planar guiding face on which the cylindrical face of a pin can move.