InvertModL function Null safety

Uint8List InvertModL(
  1. Uint8List z
)

///////////////////SPACEMESH SPECIFIC////////////////////////

Implementation

// Copyright 2019 Spacemesh Authors
// edwards25519 invert mod l

// InvertModL computes z mod l and puts the result into out
Uint8List InvertModL(Uint8List z) {
  Uint8List t0 = new Uint8List(32);
  Uint8List t1 = new Uint8List(32);
  Uint8List t2 = new Uint8List(32);
  Uint8List t3 = new Uint8List(32);
  Uint8List t4 = new Uint8List(32);
  Uint8List t5 = new Uint8List(32);
  Uint8List tz = new Uint8List(32);

  t1 = z;
  squareModL(t0, z); // 2^1
  multModL(t2, t0, z); // 2^1 + 2^0
  for (var i = 1; i < 2; i++) {
    // 2^2
    squareModL(t0, t0);
  }
  multModL(t3, t0, t2); // 2^2 + 2^1 + 2^0
  for (var i = 1; i < 2; i++) {
    // 2^3
    squareModL(t0, t0);
  }
  multModL(t4, t0, t3); // 2^3 + 2^2 + 2^1 + 2^0
  for (var i = 1; i < 2; i++) {
    // 2^4
    squareModL(t0, t0);
  }
  multModL(t5, t0, t4); // 2^4 + 2^3 + 2^2 + 2^1 + 2^0

  tz = new Uint8List.fromList(t1);

  for (var i = 1; i < 129; i++) {
    // 2^128
    squareModL(tz, tz);
  }
  multModL(tz, tz, t1); // tz = 252, 124
  for (var i = 1; i < 3; i++) {
    // 2^2
    squareModL(tz, tz);
  }
  multModL(tz, tz, t1); // 2^124 + 2^122
  for (var i = 1; i < 5; i++) {
    // 2^4
    squareModL(tz, tz);
  }
  multModL(tz, tz, t2); // 2^124 + 2^122 + 2^119 + 2^118
  for (var i = 1; i < 6; i++) {
    // 2^5
    squareModL(tz, tz);
  }
  multModL(tz, tz, t4); // 124,122,119,118,116..113
  for (var i = 1; i < 7; i++) {
    // 2^6
    squareModL(tz, tz);
  }
  multModL(tz, tz, t5); // 124,122,119,118,116..113, 111..107
  for (var i = 1; i < 6; i++) {
    // 2^5
    squareModL(tz, tz);
  }
  multModL(tz, tz, t3); // 124,122,119,118,116..113, 111..107, 104..102
  for (var i = 1; i < 6; i++) {
    // 2^5
    squareModL(tz, tz);
  }
  multModL(tz, tz, t4); // **124.....102**, 100..97
  for (var i = 1; i < 3; i++) {
    // 2^2
    squareModL(tz, tz);
  }
  multModL(tz, tz, t1); // **124.....102**, 100..97, 95
  for (var i = 1; i < 3; i++) {
    // 2^2
    squareModL(tz, tz);
  }
  multModL(tz, tz, t1); // **124.....102**, 100..97, 95, 93
  for (var i = 1; i < 5; i++) {
    // 2^4
    squareModL(tz, tz);
  }
  multModL(tz, tz, t1); // **124.....102**, 100..97, 95, 93, 89
  for (var i = 1; i < 6; i++) {
    // 2^5
    squareModL(tz, tz);
  }
  multModL(tz, tz, t4); // **124.....102**, 100..97, 95,93,89,87..84
  for (var i = 1; i < 6; i++) {
    // 2^5
    squareModL(tz, tz);
  }
  multModL(tz, tz, t4); // **124.....102**, 100..97, 95,93,89,87..84, 82..79
  for (var i = 1; i < 6; i++) {
    // 2^5
    squareModL(tz, tz);
  }
  multModL(
      tz, tz, t3); // **124.....102**, 100..97, 95,93,89,87..84, 82..79, 76..74
  for (var i = 1; i < 5; i++) {
    // 2^4
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t2); // **124.....102**, 100..97, 95,93,89,87..84, 82..79, 76..74 ,71,70
  for (var i = 1; i < 3; i++) {
    // 2^2
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t1); // **124.....102**, 100..97, 95,93,89,87..84, 82..79, 76..74 ,71,70,68
  for (var i = 1; i < 4; i++) {
    // 2^3
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t2); // **124.....102**, 100..97, 95,93,89,87..84, 82..79, 76..74 ,71,70,68,66,65
  for (var i = 1; i < 4; i++) {
    // 2^3
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t1); // **124.....102**, 100..97, 95,93,89,87..84, 82..79, 76..74 ,71,70,68,66,65,62
  for (var i = 1; i < 4; i++) {
    // 2^3
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t2); // **124.....102**, 100..97, 95,93,89,87..84, 82..79, 76..74 ,71,70,68,66,65,62,60,59
  for (var i = 1; i < 8; i++) {
    // 2^7
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t1); // **124.....102**, 100..97, 95,93,89,87..84, 82..79, 76..74 ,71,70,68,66,65,62,60,59,52
  for (var i = 1; i < 4; i++) {
    // 2^3
    squareModL(tz, tz);
  }
  multModL(tz, tz, t1); // **124.....102**, **100.....52**, 49
  for (var i = 1; i < 5; i++) {
    // 2^4
    squareModL(tz, tz);
  }
  multModL(tz, tz, t2); // **124.....102**, **100.....52**, 49,46,45
  for (var i = 1; i < 6; i++) {
    // 2^5
    squareModL(tz, tz);
  }
  multModL(tz, tz, t2); // **124.....102**, **100.....52**, 49,46,45,41,40
  for (var i = 1; i < 6; i++) {
    // 2^5
    squareModL(tz, tz);
  }
  multModL(tz, tz, t2); // **124.....102**, **100.....52**, 49,46,45,41,40,36,35
  for (var i = 1; i < 3; i++) {
    // 2^2
    squareModL(tz, tz);
  }
  multModL(
      tz, tz, t1); // **124.....102**, **100.....52**, 49,46,45,41,40,36,35,33
  for (var i = 1; i < 4; i++) {
    // 2^3
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t1); // **124.....102**, **100.....52**, 49,46,45,41,40,36,35,33,30
  for (var i = 1; i < 5; i++) {
    // 2^4
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t3); // **124.....102**, **100.....52**, 49,46,45,41,40,36,35,33,30,28..26
  for (var i = 1; i < 7; i++) {
    // 2^6
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t4); // **124.....102**, **100.....52**, 49,46,45,41,40,36,35,33,30,28..26, 23..20
  for (var i = 1; i < 3; i++) {
    // 2^2
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t1); // **124.....102**, **100.....52**, 49,46,45,41,40,36,35,33,30,28..26, 23..20, 18
  for (var i = 1; i < 5; i++) {
    // 2^4
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t3); // **124.....102**, **100.....52**, 49,46,45,41,40,36,35,33,30,28..26, 23..20, 18,16..14
  for (var i = 1; i < 3; i++) {
    // 2^2
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t1); // **124.....102**, **100.....52**, 49,46,45,41,40,36,35,33,30,28..26, 23..20, 18,16..14, 12
  for (var i = 1; i < 8; i++) {
    // 2^7
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t5); // **124.....102**, **100.....52**, 49,46,45,41,40,36,35,33,30,28..26, 23..20, 18,16..14, 12,9..5
  for (var i = 1; i < 3; i++) {
    // 2^2
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t1); // **124.....102**, **100.....52**, 49,46,45,41,40,36,35,33,30,28..26, 23..20, 18,16..14, 12,9..5, 3
  for (var i = 1; i < 4; i++) {
    // 2^3
    squareModL(tz, tz);
  }
  multModL(tz, tz,
      t2); // **124.....102**, **100.....52**, 49,46,45,41,40,36,35,33,30,28..26, 23..20, 18,16..14, 12,9..5, 3,1,0

  return tz;
}