Module ct 

Constant-time primitives.

Every routine here executes in time independent of the values of its secret inputs (lengths are considered public). The implementations avoid branches and table lookups on secret data, and pass results through core::hint::black_box to stop the optimizer from re-introducing a branch when it proves a value is boolean.

Structs

Choice

A branch-free boolean whose value is never observable through control flow.

Functions

cmov

Copy src over dst only when c is true, in constant time.

cswap

Conditionally swap two equal-length buffers in constant time.

eq

Constant-time equality over two byte slices.

is_zero

Constant-time check that every byte of x is zero.

lt_be

Constant-time a < b over big-endian byte strings of equal length.

select_u8

Branch-free select: returns a when c is true, otherwise b.

select_u32

Branch-free select over u32.

select_u64

Branch-free select over u64.

verify

Constant-time byte-slice comparison returning a plain bool.