Apparatus and method for generating random numbers. In accordance with some embodiments, a first multi-bit string of entropy values is derived from a first entropy source having a first trust level and a different, second multi-bit string of entropy values is derived from a second entropy source having a different, second trust level. The first and second multi-bit strings of entropy values are combined in relation to the associated first and second trust levels to generate a multi-bit random number. The multi-bit random number is used as an input to a cryptographic function.