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Remove mem.timingSafeEqual() for now

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This requires assembly implementations, and is not needed for
signature verification.

Thanks @daurnimator
This commit is contained in:
Frank Denis
2020-08-14 16:08:26 +02:00
committed by Andrew Kelley
parent 3f0d80f25e
commit 5f9953f41f
2 changed files with 1 additions and 26 deletions
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2
lib/std/crypto/25519/ed25519.zig
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@@ -96,7 +96,7 @@ pub const Ed25519 = struct {
const p = try a.neg().mul(hram);
const check = (try Curve.basePoint().mul(s.*)).add(p).toBytes();
if (mem.timingSafeEqual(u8, &check, r) == false) {
if (mem.eql(u8, &check, r) == false) {
return error.InvalidSignature;
}
}

25
lib/std/mem.zig
View File

@@ -334,31 +334,6 @@ test "mem.secureZero" {
testing.expectEqualSlices(u8, a[0..], b[0..]);
}
/// Constant-time (for a given length) comparison.
pub fn timingSafeEqual(comptime T: type, a: []const T, b: []const T) bool {
const length = a.len;
if (length != b.len) {
return false;
}
const ap = @ptrCast([*]const volatile T, a.ptr);
const bp = @ptrCast([*]const volatile T, b.ptr);
var c: u8 = 0;
var i: usize = 0;
while (i < length) : (i += 1) {
c |= a[i] ^ b[i];
}
return c == 0;
}
test "mem.timingSafeEqual" {
var a = [_]u8{0xfe} ** 8;
var b = [_]u8{0xfe} ** 8;
testing.expect(timingSafeEqual(u8, &a, &b));
a[0] += 1;
testing.expect(!timingSafeEqual(u8, &a, &b));
}
/// Initializes all fields of the struct with their default value, or zero values if no default value is present.
/// If the field is present in the provided initial values, it will have that value instead.
/// Structs are initialized recursively.