Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

doc: add note about timingSafeEqual for TypedArray #36323

Closed
wants to merge 2 commits into from
Closed

doc: add note about timingSafeEqual for TypedArray #36323

Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
89b0d23
doc: add note about timingSafeEqual for TypedArray
tniessen Nov 30, 2020
dd16890
fixup
tniessen Dec 12, 2020
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 4 additions & 1 deletion doc/api/crypto.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3383,7 +3383,10 @@ comparing HMAC digests or secret values like authentication cookies or
[capability urls](https://www.w3.org/TR/capability-urls/).

`a` and `b` must both be `Buffer`s, `TypedArray`s, or `DataView`s, and they
must have the same length.
must have the same byte length.

If at least one of `a` and `b` is a `TypedArray`, the result may depend on
the platform byte order.
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

may depend sounds like this isn’t deterministic, but I assume it is? It’s always going to depend on the platform byte order, right?

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Good point! My thinking was that the result of some inputs (e.g., timingSafeEqual(new Uint8Array([1, 1]), new Uint16Array([0x0101]))) does not depend on the platform byte order, but that's probably not what others would take away from the way I worded it.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yeah, I see … maybe I would say something like If at least one of `a` and `b` is a `TypedArray` with more than one byte per entry, like `Uint16Array`, the result will be computed using platform byte order?

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Sorry about the delay, fixed!


Use of `crypto.timingSafeEqual` does not guarantee that the *surrounding* code
is timing-safe. Care should be taken to ensure that the surrounding code does
Expand Down