TCG design specification of TPM and nonce creation I am reading TPM Main Part 1 Design Principles (PDF) which states:


  The creation of all nonce values MUST use the next $n$ bits from the TPM RNG.


I do not know what this means, or how to find out what it means. What is “the next $n$ bits”?  There is no other comment or hint on this section which might explain $n$
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In cryptography, $n$ is frequently used to point to some specific number.

The statement


  The creation of all nonce values MUST use the next $n$ bits from the TPM RNG.


simply clarifies that all nonce values have to be generated using the TPM RNG, by using/extracting the next $n$ number of bits from that RNG. Maybe it helps to think of “$n$ bits” as “x number of bits”, where “x” is the amount specified in the paper.

So, if a paper explains that (for example) a “nonce size is 64 bits” and later states you have to extract the next $n$ bits from some function or RNG to initialize that nonce, $n$ would be 64. Taking this example, the line you’ve stumbled upon would mean: “The creation of all nonce values MUST use the next 64 bits from the TPM RNG.” 

But please note that that‘s merely an example. If a paper would point to 32 bits, or 128 bits, or whatever other number of bits, $n$ would have to be interpreted as another number/count/amount accordingly. Also note that we are talking about bits in this specific case and paper. Other papers might as well use $n$ to mention “$n$ bytes” or other units (eg: “$n$ rounds of encryption”).