TPM Main Specification Level 2(PDF), Part 1 – Design Principles Version 1.2, Revision 116, [2017-09-12], (原始內容存檔(PDF)於2021-02-24), Our definition of the RNG allows implementation of a Pseudo Random Number Generator (PRNG) algorithm. However, on devices where a hardware source of entropy is available, a PRNG need not be implemented. This specification refers to both RNG and PRNG implementations as the RNG mechanism. There is no need to distinguish between the two at the TCG specification level.