private static unsafe bool Loop23Hash(Sha256Fo sha, uint *wPt, uint *hPt, byte *tmp, ICompareService comparer)
{
// The added value below is the fixed first char('S')=0x53 shifted left 24 places
wPt[0] = 0b01010011_00000000_00000000_00000000U | (uint)tmp[1] << 16 | (uint)tmp[2] << 8 | tmp[3];
wPt[1] = (uint)tmp[4] << 24 | (uint)tmp[5] << 16 | (uint)tmp[6] << 8 | tmp[7];
wPt[2] = (uint)tmp[8] << 24 | (uint)tmp[9] << 16 | (uint)tmp[10] << 8 | tmp[11];
wPt[3] = (uint)tmp[12] << 24 | (uint)tmp[13] << 16 | (uint)tmp[14] << 8 | tmp[15];
wPt[4] = (uint)tmp[16] << 24 | (uint)tmp[17] << 16 | (uint)tmp[18] << 8 | tmp[19];
// The added value below is the SHA padding and the last added ? char equal to 0x3f shifted right 8 places
wPt[5] = (uint)tmp[20] << 24 | (uint)tmp[21] << 16 | 0b00000000_00000000_00111111_10000000U;
// from 6 to 14 = 0
wPt[15] = 184; // 23 *8 = 184
sha.Init(hPt);
sha.Compress23(hPt, wPt);
if ((hPt[0] & 0b11111111_00000000_00000000_00000000U) == 0)
{
// The actual key is SHA256 of 22 char key (without '?')
// SHA working vector is already set, only the last 2 bytes ('?' and pad) and the length have to change
wPt[5] ^= 0b00000000_00000000_10111111_10000000U;
// from 6 to 14 (remain) = 0
wPt[15] = 176; // 22 *8 = 176
sha.Init(hPt);
sha.Compress22(hPt, wPt);
return(comparer.Compare(hPt));
}
public unsafe void Compress23Test()
{
int dataLen = 23;
byte[] data = GetRandomBytes(dataLen);
byte[] expected = ComputeSingleSha(data);
using Sha256Fo sha = new Sha256Fo();
fixed(uint *hPt = &sha.hashState[0], wPt = &sha.w[0])
{
int dIndex = 0;
for (int i = 0; i < 5; i++, dIndex += 4)
{
wPt[i] = (uint)((data[dIndex] << 24) | (data[dIndex + 1] << 16) | (data[dIndex + 2] << 8) | data[dIndex + 3]);
}
wPt[5] = (uint)((data[20] << 24) | (data[21] << 16) | (data[22] << 8) | 0b00000000_00000000_00000000_10000000U);
wPt[15] = (uint)dataLen * 8;
sha.Init(hPt);
sha.Compress23(hPt, wPt);
byte[] actual = sha.GetBytes(hPt);
Assert.Equal(expected, actual);
}
}
private unsafe bool Loop23()
{
// The actual data that is changing is 22 bytes (22 char long mini key) with a fixed starting character ('S')
// plus an additional byte added to the end (char('?')=0x3f) during checking loop.
// Checksum is replaced by checking if first byte of hash result is zero.
// The actual key itself is the hash of the same 22 bytes (without '?') using a single SHA256
// Note characters are decoded using UTF-8
var cartesian = CartesianProduct.Create(Enumerable.Repeat(Encoding.UTF8.GetBytes(ConstantsFO.Base58Chars), missCount));
using Sha256Fo sha = new Sha256Fo();
bool success = false;
byte[] temp = new byte[precomputed.Length];
fixed(uint *hPt = &sha.hashState[0], wPt = &sha.w[0])
fixed(byte *pre = &precomputed[0], tmp = &temp[0])
fixed(int *mi = &missingIndexes[0])
{
foreach (var item in cartesian)
{
Buffer.MemoryCopy(pre, tmp, 22, 22);
int mis = 0;
foreach (var keyItem in item)
{
tmp[mi[mis]] = keyItem;
mis++;
}
// The added value below is the fixed first char(S)=0x53 shifted left 24 places
wPt[0] = 0b01010011_00000000_00000000_00000000U | (uint)tmp[1] << 16 | (uint)tmp[2] << 8 | tmp[3];
wPt[1] = (uint)tmp[4] << 24 | (uint)tmp[5] << 16 | (uint)tmp[6] << 8 | tmp[7];
wPt[2] = (uint)tmp[8] << 24 | (uint)tmp[9] << 16 | (uint)tmp[10] << 8 | tmp[11];
wPt[3] = (uint)tmp[12] << 24 | (uint)tmp[13] << 16 | (uint)tmp[14] << 8 | tmp[15];
wPt[4] = (uint)tmp[16] << 24 | (uint)tmp[17] << 16 | (uint)tmp[18] << 8 | tmp[19];
// The added value below is the SHA padding and the last added ? char equal to 0x3f shifted right 8 places
wPt[5] = (uint)tmp[20] << 24 | (uint)tmp[21] << 16 | 0b00000000_00000000_00111111_10000000U;
// from 6 to 14 = 0
wPt[15] = 184; // 23 *8 = 184
sha.Init(hPt);
sha.Compress23(hPt, wPt);
if ((hPt[0] & 0b11111111_00000000_00000000_00000000U) == 0)
{
// The actual key is SHA256 of 22 char key (without '?')
// SHA working vector is already set, only the last 2 bytes ('?' and pad) and the length have to change
wPt[5] ^= 0b00000000_00000000_10111111_10000000U;
// from 6 to 14 (remain) = 0
wPt[15] = 176; // 22 *8 = 176
sha.Init(hPt);
sha.Compress22(hPt, wPt);
if (comparer.Compare(sha.GetBytes(hPt)))
{
SetResult(item);
success = true;
break;
}
}
}
}
return(success);
}