funcConstantTimeByteEq¶

func ConstantTimeByteEq(x, yuint8)int

ConstantTimeByteEq returns 1 if x == y and 0 otherwise.

funcConstantTimeCompare¶

func ConstantTimeCompare(x, y []byte)int

ConstantTimeCompare returns 1 if the two slices, x and y, have equal contentsand 0 otherwise. The time taken is a function of the length of the slices andis independent of the contents. If the lengths of x and y do not match itreturns 0 immediately.

funcConstantTimeCopy¶

func ConstantTimeCopy(vint, x, y []byte)

ConstantTimeCopy copies the contents of y into x (a slice of equal length)if v == 1. If v == 0, x is left unchanged. Its behavior is undefined if vtakes any other value.

funcConstantTimeEq¶

func ConstantTimeEq(x, yint32)int

ConstantTimeEq returns 1 if x == y and 0 otherwise.

funcConstantTimeLessOrEq¶added ingo1.2

func ConstantTimeLessOrEq(x, yint)int

ConstantTimeLessOrEq returns 1 if x <= y and 0 otherwise.Its behavior is undefined if x or y are negative or > 2**31 - 1.

funcConstantTimeSelect¶

func ConstantTimeSelect(v, x, yint)int

ConstantTimeSelect returns x if v == 1 and y if v == 0.Its behavior is undefined if v takes any other value.

funcWithDataIndependentTiming¶added ingo1.24.0

func WithDataIndependentTiming(f func())

WithDataIndependentTiming enables architecture specific features which ensurethat the timing of specific instructions is independent of their inputsbefore executing f. On f returning it disables these features.

WithDataIndependentTiming should only be used when f is written to make useof constant-time operations. WithDataIndependentTiming does not makevariable-time code constant-time.

WithDataIndependentTiming may lock the current goroutine to the OS thread forthe duration of f. Calls to WithDataIndependentTiming may be nested.

On Arm64 processors with FEAT_DIT, WithDataIndependentTiming enablesPSTATE.DIT. Seehttps://developer.arm.com/documentation/ka005181/1-0/?lang=en.

Currently, on all other architectures WithDataIndependentTiming executes f immediatelywith no other side-effects.

funcXORBytes¶added ingo1.20

func XORBytes(dst, x, y []byte)int

XORBytes sets dst[i] = x[i] ^ y[i] for all i < n = min(len(x), len(y)),returning n, the number of bytes written to dst.

If dst does not have length at least n,XORBytes panics without writing anything to dst.

dst and x or y may overlap exactly or not at all,otherwise XORBytes may panic.