One or more keys are derived from a master key by executing a plurality of encryption operations. A first encryption operation uses the master key to encrypt a plaintext input having a plurality of bytes. Multiple intermediate encryption operations are performed using a respective intermediate key generated by a previous encryption operation to encrypt respective plaintext inputs having a number of bytes. At least two bytes of a plaintext input have values based on a respective set of bits of a plurality of sets of bits of an initialization vector, wherein individual bits of the respective set of bits are introduced into respective individual bytes of the plaintext input and the respective set of bits has at least two bits and at most a number of bits equal to the number of bytes of the plaintext input.