1. A method to generate a true random number for use in a cryptographic operation, the method operative in a mobile device comprising an operating system, and one or more hardware devices, comprising: allocating random available storage areas of a data store of the mobile device to store entropy data in an entropy data pool; pooling into the data store of the mobile device entropy data generated from the one or more hardware devices to form the entropy data pool; and determining whether sufficient entropy data is present in the data store in response to a request, including responsive to sufficient entropy data being present in the data store, retrieving entropy data from particular locations in the data store; using the entropy data retrieved to generate a true random number, and clearing the particular locations from which the entropy data was retrieved; and responsive to insufficient entropy data being present in the data store, using an operating system-based random number generator to generate the true random number.