Disclosed herein are systems, methods, and non-transitory computer-readable storage media for key space division and sub-key derivation for mixed media digital rights management content and secure digital asset distribution. A system practicing the exemplary method derives a set of family keys from a master key associated with an encrypted media asset using a one-way function, wherein each family key is uniquely associated with a respective client platform type, wherein the master key is received from a server account database, and identifies a client platform type for a client device and a corresponding family key from the set of family keys. The system encrypts an encrypted media asset with the corresponding family key to yield a platform-specific encrypted media asset, and transmits the platform-specific encrypted media asset to the client device. Thus, different client devices receive device-specific encrypted assets which can be all derived based on the same master key.