CHAM: a family of lightweight block ciphers for resource-constrained devices. In this paper, we propose a family of lightweight block ciphers CHAM that has remarkable efficiency on resource-constrained devices. The family consists of three ciphers, CHAM-64/128, CHAM-128/128, and CHAM-128/256 which are of the generalized 4-branch Feistel structure based on ARX (Addition, Rotation, XOR) operations.{par}In hardware implementations, CHAM requires smaller areas (73% on average) than SIMON [8] through the use of a stateless-on-the-fly key schedule which does not require updating a key state. Regarding software performance, it achieves outstanding figures on typical IoT platforms in terms of the balanced performance metrics introduced in earlier works. It shows a level of performance competitive to SPECK [8] mainly due to small memory size required for round keys. According to our cryptanalysis results, CHAM is secure against known attacks.