Increase auth nonce entropy

[iamacook]

Summary

This increases the nonce entropy the auth implementation to match that of the official SiWe implementation (18 characters).

[coveralls]

Pull Request Test Coverage Report for Build 8627601648

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.5%) to 93.179%

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Files with Coverage Reduction	New Missed Lines	%
src/routes/transactions/entities/tests/human-description.builder.ts	2	60.0%

Totals
Change from base Build 8613582353:	0.5%
Covered Lines:	4518
Relevant Lines:	4706

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💛 - Coveralls

[hectorgomezv]

This generates 34 hex characters strings, as nonce if I'm not wrong. The implementation referenced above produces 96 bits (so 48 hex characters), right? I don't have an opinion about the size, both seem enough, but maybe we can add a comment documenting the decision?

[iamacook]

I think the comment is not clear enough (I tried to simplify/extract explicit code from the example packages). Is there something in particular I could adjust to make it more understandable?

  const ALPHANUMERIC = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  const length = Math.ceil(96 / (Math.log(ALPHANUMERIC.length) / Math.LN2)) // 17 characters long

Note: I tested the official package again and calling generateNonce of siwe returned the following: "UhC3yE7xXrVU6t0Qs" which is 17 characters.

[hectorgomezv]

Oh, I see, thanks for explaining, the length matches the official package one then 👍🏻

[iamacook]

I looked into our implementation and you're correct. I'll mark this as a draft and revisit this now.

[iamacook]

I adjusted the nonce length to 18 as of b2ccdf2.

As we're using the typed array to generate random values, we can't use 17 as we'd need 8.5 elements. I think it's better to stick with 18 as it's a) more secure and b) simpler than then removing a character after generation, for example. What do you think?

[hectorgomezv]

It makes perfect sense to me, I think we are free to set the length that fits better here, 18 seems OK to me.