Lock cylinder comprising: - a stator comprising: • a central cutout extending in a transverse plane, this transverse plane dividing the stator into an inside half stator and an outside half stator, • a longitudinal hole extending along a longitudinal axis perpendicular to the transverse plane and passing through the inside and outside half-stators and the central cutout, and • a first annular face formed on the inside half-stator and a second annular face formed on the outside half-stator, these annular faces each being arranged on a respective side of the cutout, each of these first and second annular faces facing away from the longitudinal axis and having symmetry of revolution about the longitudinal axis, - a rotor mounted inside the longitudinal hole and movable in rotation about the longitudinal axis, this rotor containing inside and outside canals each opening onto a respective end of the rotor, each canal being able to accept a key for turning the rotor about the longitudinal axis if this key is a key authorized to unlock the lock, - a bit for driving the movement of a lock bolt, this bit being housed inside the cutout and comprising third and fourth annular faces (132, 134) facing towards the longitudinal axis and each having symmetry of revolution about the longitudinal axis, these third and fourth annular faces bearing directly against, respectively, the first and second annular faces of the stator so as to form a pivoting connection between the bit and the stator allowing the bit to rotate about the longitudinal axis, this bit also being mechanically attached to the rotor so as to be moved in rotation about the longitudinal axis by the rotor, - a blocking member movable between: • a blocking position in which it is in engagement with the rotor to block the rotation thereof, and • a retracted position in which it frees the rotor to turn, characterized in that: - the cylinder comprises an electronic mechanism able to move the blocking member from its blocked position into its retracted position in response to the introduction of the authorized key into either one of the inside and outside canals and, on the other hand, keep the blocking member in its blocked position in response to the introduction of an unauthorized key into either one of the inside and outside canals, and - the bit is systematically fixed, with no degree of freedom to rotate, on the rotor. - a stator comprising: • a central cutout extending in a transverse plane, this transverse plane dividing the stator into an inside half stator and an outside half stator, • a longitudinal hole extending along a longitudinal axis perpendicular to the transverse plane and passing through the inside and outside half-stators and the central cutout, and • a first annular face formed on the inside half-stator and a second annular face formed on the outside half-stator, these annular faces each being arranged on a respective side of the cutout, each of these first and second annular faces facing away from the longitudinal axis and having symmetry of revolution about the longitudinal axis, • a central cutout extending in a transverse plane, this transverse plane dividing the stator into an inside half stator and an outside half stator, • a longitudinal hole extending along a longitudinal axis perpendicular to the transverse plane and passing through the inside and outside half-stators and the central cutout, and • a first annular face formed on the inside half-stator and a second annular face formed on the outside half-stator, these annular faces each being arranged on a respective side of the cutout, each of these first and second annular faces facing away from the longitudinal axis and having symmetry of revolution about the longitudinal axis, - a rotor mounted inside the longitudinal hole and movable in rotation about the longitudinal axis, this rotor containing inside and outside canals each opening onto a respective end of the rotor, each canal being able to accept a key for turning the rotor about the longitudinal axis if this key is a key authorized to unlock the lock, - a bit for driving the movement of a lock bolt, this bit being housed inside the cutout and comprising third and fourth annular faces (132, 134) facing towards the longitudinal axis and each having symmetry of revolution about the longitudinal axis, these third and fourth annular faces bearing directly against, respectively, the first and second annular faces of the stator so as to form a pivoting connection between the bit and the stator allowing the bit to rotate about the longitudinal axis, this bit also being mechanically attached to the rotor so as to be moved in rotation about the longitudinal axis by the rotor, - a blocking member movable between: • a blocking position in which it is in engagement with the rotor to block the rotation thereof, and • a retracted position in which it frees the rotor to turn, • a blocking position in which it is in engagement with the rotor to block the rotation thereof, and • a retracted position in which it frees the rotor to turn, - the cylinder comprises an electronic mechanism able to move the blocking member from its blocked position into its retracted position in response to the introduction of the authorized key into either one of the inside and outside canals and, on the other hand, keep the blocking member in its blocked position in response to the introduction of an unauthorized key into either one of the inside and outside canals, and - the bit is systematically fixed, with no degree of freedom to rotate, on the rotor.