public equation CombineAndReduce(equation othereq)
{
long topmultiplier = 0, bottommultiplier = 0;
// This function considers "this" the top, and othereq the bottom.
// It multiplies both equations by the first coefficient of the opposite equation,
// and then subtracts the bottom from the top, eliminating the first coefficient from
// the left side, and adding coefficients to the right.
equation neweq = new equation();
othereq.KillFactors();
for (int i = 0; i < leftside.Count; i++)
{
coefficient topco = leftside[i];
coefficient bottomco = othereq.leftside[i];
if (i == 0)
{
topmultiplier = bottomco.multiplier;
bottommultiplier = topco.multiplier;
// avoid saving a coefficient because the multiplier and subtraction guarantee they cancel
}
else
{
neweq.leftside.Add(new coefficient(topco.multiplier * topmultiplier - bottomco.multiplier * bottommultiplier, topco.vindex));
}
}
for (int i = 0; i < 8; i++)
{
long multiplier = 0;
foreach (coefficient r in rightside)
{
if (r.vindex == i)
{
multiplier += (r.multiplier * topmultiplier);
}
}
foreach (coefficient r in othereq.rightside)
{
if (r.vindex == i)
{
multiplier -= (r.multiplier * bottommultiplier);
}
}
if (multiplier != 0)
{
neweq.rightside.Add(new coefficient(multiplier, i));
}
}
neweq.KillFactors();
return(neweq);
}
public equation CombineAndReduce(equation othereq)
{
long topmultiplier = 0, bottommultiplier = 0;
// This function considers "this" the top, and othereq the bottom.
// It multiplies both equations by the first coefficient of the opposite equation,
// and then subtracts the bottom from the top, eliminating the first coefficient from
// the left side, and adding coefficients to the right.
equation neweq = new equation();
othereq.KillFactors();
for (int i = 0; i < leftside.Count; i++) {
coefficient topco = leftside[i];
coefficient bottomco = othereq.leftside[i];
if (i == 0) {
topmultiplier = bottomco.multiplier;
bottommultiplier = topco.multiplier;
// avoid saving a coefficient because the multiplier and subtraction guarantee they cancel
} else {
neweq.leftside.Add(new coefficient(topco.multiplier * topmultiplier - bottomco.multiplier * bottommultiplier, topco.vindex));
}
}
for (int i = 0; i < 8; i++) {
long multiplier = 0;
foreach (coefficient r in rightside) {
if (r.vindex == i) multiplier += (r.multiplier * topmultiplier);
}
foreach (coefficient r in othereq.rightside) {
if (r.vindex == i) multiplier -= (r.multiplier * bottommultiplier);
}
if (multiplier != 0) {
neweq.rightside.Add(new coefficient(multiplier, i));
}
}
neweq.KillFactors();
return neweq;
}
public void Decode()
{
ChecksumMatched = false;
Decoded = false;
KeyPair = null;
if (PartsAccepted < PartsNeeded)
{
return;
}
BigInteger[] pc = new BigInteger[8];
for (int i = 0; i < decodedKeyParts.Count; i++)
{
byte[] g = decodedKeyParts[i];
pc[i] = new BigInteger(1, g, 4, 35);
// If there is an overflow, then add it in.
if ((g[2] & 0x80) == 0x80)
{
pc[i] = pc[i].Add(new BigInteger(((int)((g[2] & 0x60) >> 5)).ToString()).ShiftLeft(280));
Debug.WriteLine("overflow added");
}
}
List <equation> equations = new List <equation>();
// create equations for all the parts we need.
for (int i = 0; i < PartsNeeded; i++)
{
byte[] got = decodedKeyParts[i];
// extract out part number
int partnumber0 = (byte)((got[2] & 0x0e) >> 1);
equations.Add(new equation(i, PartsNeeded, partnumber0));
}
List <List <equation> > steps = new List <List <equation> >();
steps.Add(equations);
// goal: get our equation set down such that there's only one coefficient on the left side.
while (equations.Count > 1)
{
equations = solvesome(equations);
steps.Add(equations);
Debug.WriteLine("-----");
foreach (equation eq in equations)
{
Debug.WriteLine(eq.ToString());
}
}
BigInteger[] v = new BigInteger[8];
while (steps.Count > 0)
{
// pop off the last step
List <equation> laststeps = steps[steps.Count - 1];
steps.RemoveAt(steps.Count - 1);
equation laststep = laststeps[0];
Debug.WriteLine("-----");
Debug.WriteLine(laststep.ToString());
// solve for v
long divisor = laststep.leftside[0].multiplier;
laststep.divisor = laststep.leftside[0].multiplier;
laststep.leftside[0].multiplier = 1;
//foreach (coefficient c in laststep.rightside) c.divisor = divisor;
//laststep.subtractor = laststep.subtractor.Divide(new BigInteger(divisor.ToString()));
long idx = laststep.leftside[0].vindex;
v[idx] = laststep.SolveRight(pc);
Debug.WriteLine(String.Format("v({0})={1}", laststep.leftside[0].vindex, v[idx].ToString()));
// go through all other steps and see that our solved value is incorporated into the equation.
foreach (List <equation> eqbl in steps)
{
foreach (equation eqb in eqbl)
{
eqb.SolveLeft(v);
}
}
}
// xor the ones we need
BigInteger xoraccum = BigInteger.Zero;
for (int i = 0; i < PartsNeeded; i++)
{
xoraccum = xoraccum.Xor(v[i]);
}
ChecksumMatched = false;
Decoded = true;
byte[] keybytes = xoraccum.ToByteArrayUnsigned();
if (keybytes.Length > 32)
{
// if more than 32 bytes, decoding probably went wrong! truncate to 32 bytes, but force a checksum failure
byte[] newkey = new byte[32];
for (int jj = 0; jj < 32; jj++)
{
newkey[jj] = keybytes[jj];
}
keybytes = newkey;
return;
}
else if (keybytes.Length < 32)
{
byte[] array32 = new byte[32];
Array.Copy(keybytes, 0, array32, 32 - keybytes.Length, keybytes.Length);
keybytes = array32;
}
KeyPair = new KeyPair(keybytes);
// Get the bitcoin address
byte[] checksum = Util.ComputeSha256(BitcoinAddress);
int mychecksum = ((checksum[0] & 1) << 8) + checksum[1];
if (mychecksum == expectedChecksum)
{
ChecksumMatched = true;
}
}