Bug in TEd255.ModuloQ

VCL TMS Cryptography Pack
1

Hi,

There is a bug in the latest Version (5.3.3.0) of the functionTEd255.ModuloQ(var a: TEd255Array)

// ModuloQ: compute a mod Modulo_Field25519
// Input: unsigned int a[SIZE_ELT_25519]
// Output: ED25519_SUCCESS
// err from Substract

function TEd255.ModuloQ(var a: TEd255Array): integer;
var
	I: integer;
	b, h: array [0..SIZE_ELT_25519 - 1] of UInt64;
	copy_a: array [0..SIZE_ELT_25519 - 1] of UInt64;
	infQ: boolean;

begin
  FillChar(b[0], Length(b) * SizeOf(b[0]), 0);
  FillChar(h[0], Length(h) * SizeOf(h[0]), 0);
  for I := 0 to SIZE_ELT_25519 do // <- should be SIZE_ELT_25519 -1
    copy_a[I] := a[I];

TEd255Array = array [0..SIZE_ELT_25519 - 1] of UInt32;

The bug surfaced only in a Win32 Release Build. Win32 Debug and all Win64-Builds work (by luck).

Please find a Sample to reproduce the bug with delphi 13.

TmsCryptoBugReport.zip (4.6 KB)

kind regards

Stefan