Abstract: A cylinder lock assembly includes a core, a key plug mounted for rotation in the core, and a key. The key plug is formed to include a keyway and a plurality of tumbler pin bores opening into the keyway. The key has a bow and a blade appended to the bow. The blade includes a bitted portion and includes a stop shoulder at the tip of the blade for positioning the bitted portion in alignment with the tumbler pin bores. A separate drive member is provided on the key for rotating the key plug relative to the core to actuate the cylinder lock assembly. The drive member is located between the bitted portion and the bow and is configured to cooperate with a bottom portion of the key blade to provide the primary torque or force for rotating the key plug in response to turning of the key in the cylinder lock assembly so that the bitted portion and an offset portion of the blade not carry substantial torque transmission load between the key and the key plug to rotate the key plug in the core.