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Diffstat (limited to 'crypto/src/math/BigInteger.cs')
| -rw-r--r-- | crypto/src/math/BigInteger.cs | 3141 |
1 files changed, 3141 insertions, 0 deletions
diff --git a/crypto/src/math/BigInteger.cs b/crypto/src/math/BigInteger.cs new file mode 100644 index 000000000..d52c0f83c --- /dev/null +++ b/crypto/src/math/BigInteger.cs @@ -0,0 +1,3141 @@ +using System; +using System.Collections; +using System.Diagnostics; +using System.Globalization; +using System.Text; + +using Org.BouncyCastle.Utilities; + +namespace Org.BouncyCastle.Math +{ +#if !(NETCF_1_0 || NETCF_2_0 || SILVERLIGHT || PORTABLE) + [Serializable] +#endif + public class BigInteger + { + // The primes b/w 2 and ~2^10 + /* + 3 5 7 11 13 17 19 23 29 + 31 37 41 43 47 53 59 61 67 71 + 73 79 83 89 97 101 103 107 109 113 + 127 131 137 139 149 151 157 163 167 173 + 179 181 191 193 197 199 211 223 227 229 + 233 239 241 251 257 263 269 271 277 281 + 283 293 307 311 313 317 331 337 347 349 + 353 359 367 373 379 383 389 397 401 409 + 419 421 431 433 439 443 449 457 461 463 + 467 479 487 491 499 503 509 521 523 541 + 547 557 563 569 571 577 587 593 599 601 + 607 613 617 619 631 641 643 647 653 659 + 661 673 677 683 691 701 709 719 727 733 + 739 743 751 757 761 769 773 787 797 809 + 811 821 823 827 829 839 853 857 859 863 + 877 881 883 887 907 911 919 929 937 941 + 947 953 967 971 977 983 991 997 + 1009 1013 1019 1021 1031 + */ + + // Each list has a product < 2^31 + private static readonly int[][] primeLists = new int[][] + { + new int[]{ 3, 5, 7, 11, 13, 17, 19, 23 }, + new int[]{ 29, 31, 37, 41, 43 }, + new int[]{ 47, 53, 59, 61, 67 }, + new int[]{ 71, 73, 79, 83 }, + new int[]{ 89, 97, 101, 103 }, + + new int[]{ 107, 109, 113, 127 }, + new int[]{ 131, 137, 139, 149 }, + new int[]{ 151, 157, 163, 167 }, + new int[]{ 173, 179, 181, 191 }, + new int[]{ 193, 197, 199, 211 }, + + new int[]{ 223, 227, 229 }, + new int[]{ 233, 239, 241 }, + new int[]{ 251, 257, 263 }, + new int[]{ 269, 271, 277 }, + new int[]{ 281, 283, 293 }, + + new int[]{ 307, 311, 313 }, + new int[]{ 317, 331, 337 }, + new int[]{ 347, 349, 353 }, + new int[]{ 359, 367, 373 }, + new int[]{ 379, 383, 389 }, + + new int[]{ 397, 401, 409 }, + new int[]{ 419, 421, 431 }, + new int[]{ 433, 439, 443 }, + new int[]{ 449, 457, 461 }, + new int[]{ 463, 467, 479 }, + + new int[]{ 487, 491, 499 }, + new int[]{ 503, 509, 521 }, + new int[]{ 523, 541, 547 }, + new int[]{ 557, 563, 569 }, + new int[]{ 571, 577, 587 }, + + new int[]{ 593, 599, 601 }, + new int[]{ 607, 613, 617 }, + new int[]{ 619, 631, 641 }, + new int[]{ 643, 647, 653 }, + new int[]{ 659, 661, 673 }, + + new int[]{ 677, 683, 691 }, + new int[]{ 701, 709, 719 }, + new int[]{ 727, 733, 739 }, + new int[]{ 743, 751, 757 }, + new int[]{ 761, 769, 773 }, + + new int[]{ 787, 797, 809 }, + new int[]{ 811, 821, 823 }, + new int[]{ 827, 829, 839 }, + new int[]{ 853, 857, 859 }, + new int[]{ 863, 877, 881 }, + + new int[]{ 883, 887, 907 }, + new int[]{ 911, 919, 929 }, + new int[]{ 937, 941, 947 }, + new int[]{ 953, 967, 971 }, + new int[]{ 977, 983, 991 }, + + new int[]{ 997, 1009, 1013 }, + new int[]{ 1019, 1021, 1031 }, + }; + + private static readonly int[] primeProducts; + + private const long IMASK = 0xffffffffL; + private static readonly ulong UIMASK = (ulong)IMASK; + + private static readonly int[] ZeroMagnitude = new int[0]; + private static readonly byte[] ZeroEncoding = new byte[0]; + + public static readonly BigInteger Zero = new BigInteger(0, ZeroMagnitude, false); + public static readonly BigInteger One = createUValueOf(1); + public static readonly BigInteger Two = createUValueOf(2); + public static readonly BigInteger Three = createUValueOf(3); + public static readonly BigInteger Ten = createUValueOf(10); + + private static readonly int chunk2 = 1; // TODO Parse 64 bits at a time + private static readonly BigInteger radix2 = ValueOf(2); + private static readonly BigInteger radix2E = radix2.Pow(chunk2); + + private static readonly int chunk10 = 19; + private static readonly BigInteger radix10 = ValueOf(10); + private static readonly BigInteger radix10E = radix10.Pow(chunk10); + + private static readonly int chunk16 = 16; + private static readonly BigInteger radix16 = ValueOf(16); + private static readonly BigInteger radix16E = radix16.Pow(chunk16); + + private static readonly Random RandomSource = new Random(); + + private const int BitsPerByte = 8; + private const int BitsPerInt = 32; + private const int BytesPerInt = 4; + + static BigInteger() + { + primeProducts = new int[primeLists.Length]; + + for (int i = 0; i < primeLists.Length; ++i) + { + int[] primeList = primeLists[i]; + int product = primeList[0]; + for (int j = 1; j < primeList.Length; ++j) + { + product *= primeList[j]; + } + primeProducts[i] = product; + } + } + + private int sign; // -1 means -ve; +1 means +ve; 0 means 0; + private int[] magnitude; // array of ints with [0] being the most significant + private int nBits = -1; // cache BitCount() value + private int nBitLength = -1; // cache calcBitLength() value + private long mQuote = -1L; // -m^(-1) mod b, b = 2^32 (see Montgomery mult.) + + private static int GetByteLength( + int nBits) + { + return (nBits + BitsPerByte - 1) / BitsPerByte; + } + + private BigInteger( + int signum, + int[] mag, + bool checkMag) + { + if (checkMag) + { + int i = 0; + while (i < mag.Length && mag[i] == 0) + { + ++i; + } + + if (i == mag.Length) + { + this.sign = 0; + this.magnitude = ZeroMagnitude; + } + else + { + this.sign = signum; + + if (i == 0) + { + this.magnitude = mag; + } + else + { + // strip leading 0 words + this.magnitude = new int[mag.Length - i]; + Array.Copy(mag, i, this.magnitude, 0, this.magnitude.Length); + } + } + } + else + { + this.sign = signum; + this.magnitude = mag; + } + } + + public BigInteger( + string value) + : this(value, 10) + { + } + + public BigInteger( + string str, + int radix) + { + if (str.Length == 0) + throw new FormatException("Zero length BigInteger"); + + NumberStyles style; + int chunk; + BigInteger r; + BigInteger rE; + + switch (radix) + { + case 2: + // Is there anyway to restrict to binary digits? + style = NumberStyles.Integer; + chunk = chunk2; + r = radix2; + rE = radix2E; + break; + case 10: + // This style seems to handle spaces and minus sign already (our processing redundant?) + style = NumberStyles.Integer; + chunk = chunk10; + r = radix10; + rE = radix10E; + break; + case 16: + // TODO Should this be HexNumber? + style = NumberStyles.AllowHexSpecifier; + chunk = chunk16; + r = radix16; + rE = radix16E; + break; + default: + throw new FormatException("Only bases 2, 10, or 16 allowed"); + } + + + int index = 0; + sign = 1; + + if (str[0] == '-') + { + if (str.Length == 1) + throw new FormatException("Zero length BigInteger"); + + sign = -1; + index = 1; + } + + // strip leading zeros from the string str + while (index < str.Length && Int32.Parse(str[index].ToString(), style) == 0) + { + index++; + } + + if (index >= str.Length) + { + // zero value - we're done + sign = 0; + magnitude = ZeroMagnitude; + return; + } + + ////// + // could we work out the max number of ints required to store + // str.Length digits in the given base, then allocate that + // storage in one hit?, then Generate the magnitude in one hit too? + ////// + + BigInteger b = Zero; + + + int next = index + chunk; + + if (next <= str.Length) + { + do + { + string s = str.Substring(index, chunk); + ulong i = ulong.Parse(s, style); + BigInteger bi = createUValueOf(i); + + switch (radix) + { + case 2: + // TODO Need this because we are parsing in radix 10 above + if (i > 1) + throw new FormatException("Bad character in radix 2 string: " + s); + + // TODO Parse 64 bits at a time + b = b.ShiftLeft(1); + break; + case 16: + b = b.ShiftLeft(64); + break; + default: + b = b.Multiply(rE); + break; + } + + b = b.Add(bi); + + index = next; + next += chunk; + } + while (next <= str.Length); + } + + if (index < str.Length) + { + string s = str.Substring(index); + ulong i = ulong.Parse(s, style); + BigInteger bi = createUValueOf(i); + + if (b.sign > 0) + { + if (radix == 2) + { + // NB: Can't reach here since we are parsing one char at a time + Debug.Assert(false); + + // TODO Parse all bits at once +// b = b.ShiftLeft(s.Length); + } + else if (radix == 16) + { + b = b.ShiftLeft(s.Length << 2); + } + else + { + b = b.Multiply(r.Pow(s.Length)); + } + + b = b.Add(bi); + } + else + { + b = bi; + } + } + + // Note: This is the previous (slower) algorithm + // while (index < value.Length) + // { + // char c = value[index]; + // string s = c.ToString(); + // int i = Int32.Parse(s, style); + // + // b = b.Multiply(r).Add(ValueOf(i)); + // index++; + // } + + magnitude = b.magnitude; + } + + public BigInteger( + byte[] bytes) + : this(bytes, 0, bytes.Length) + { + } + + public BigInteger( + byte[] bytes, + int offset, + int length) + { + if (length == 0) + throw new FormatException("Zero length BigInteger"); + + // TODO Move this processing into MakeMagnitude (provide sign argument) + if ((sbyte)bytes[offset] < 0) + { + this.sign = -1; + + int end = offset + length; + + int iBval; + // strip leading sign bytes + for (iBval = offset; iBval < end && ((sbyte)bytes[iBval] == -1); iBval++) + { + } + + if (iBval >= end) + { + this.magnitude = One.magnitude; + } + else + { + int numBytes = end - iBval; + byte[] inverse = new byte[numBytes]; + + int index = 0; + while (index < numBytes) + { + inverse[index++] = (byte)~bytes[iBval++]; + } + + Debug.Assert(iBval == end); + + while (inverse[--index] == byte.MaxValue) + { + inverse[index] = byte.MinValue; + } + + inverse[index]++; + + this.magnitude = MakeMagnitude(inverse, 0, inverse.Length); + } + } + else + { + // strip leading zero bytes and return magnitude bytes + this.magnitude = MakeMagnitude(bytes, offset, length); + this.sign = this.magnitude.Length > 0 ? 1 : 0; + } + } + + private static int[] MakeMagnitude( + byte[] bytes, + int offset, + int length) + { + int end = offset + length; + + // strip leading zeros + int firstSignificant; + for (firstSignificant = offset; firstSignificant < end + && bytes[firstSignificant] == 0; firstSignificant++) + { + } + + if (firstSignificant >= end) + { + return ZeroMagnitude; + } + + int nInts = (end - firstSignificant + 3) / BytesPerInt; + int bCount = (end - firstSignificant) % BytesPerInt; + if (bCount == 0) + { + bCount = BytesPerInt; + } + + if (nInts < 1) + { + return ZeroMagnitude; + } + + int[] mag = new int[nInts]; + + int v = 0; + int magnitudeIndex = 0; + for (int i = firstSignificant; i < end; ++i) + { + v <<= 8; + v |= bytes[i] & 0xff; + bCount--; + if (bCount <= 0) + { + mag[magnitudeIndex] = v; + magnitudeIndex++; + bCount = BytesPerInt; + v = 0; + } + } + + if (magnitudeIndex < mag.Length) + { + mag[magnitudeIndex] = v; + } + + return mag; + } + + public BigInteger( + int sign, + byte[] bytes) + : this(sign, bytes, 0, bytes.Length) + { + } + + public BigInteger( + int sign, + byte[] bytes, + int offset, + int length) + { + if (sign < -1 || sign > 1) + throw new FormatException("Invalid sign value"); + + if (sign == 0) + { + this.sign = 0; + this.magnitude = ZeroMagnitude; + } + else + { + // copy bytes + this.magnitude = MakeMagnitude(bytes, offset, length); + this.sign = this.magnitude.Length < 1 ? 0 : sign; + } + } + + public BigInteger( + int sizeInBits, + Random random) + { + if (sizeInBits < 0) + throw new ArgumentException("sizeInBits must be non-negative"); + + this.nBits = -1; + this.nBitLength = -1; + + if (sizeInBits == 0) + { + this.sign = 0; + this.magnitude = ZeroMagnitude; + return; + } + + int nBytes = GetByteLength(sizeInBits); + byte[] b = new byte[nBytes]; + random.NextBytes(b); + + // strip off any excess bits in the MSB + b[0] &= rndMask[BitsPerByte * nBytes - sizeInBits]; + + this.magnitude = MakeMagnitude(b, 0, b.Length); + this.sign = this.magnitude.Length < 1 ? 0 : 1; + } + + private static readonly byte[] rndMask = { 255, 127, 63, 31, 15, 7, 3, 1 }; + + public BigInteger( + int bitLength, + int certainty, + Random random) + { + if (bitLength < 2) + throw new ArithmeticException("bitLength < 2"); + + this.sign = 1; + this.nBitLength = bitLength; + + if (bitLength == 2) + { + this.magnitude = random.Next(2) == 0 + ? Two.magnitude + : Three.magnitude; + return; + } + + int nBytes = GetByteLength(bitLength); + byte[] b = new byte[nBytes]; + + int xBits = BitsPerByte * nBytes - bitLength; + byte mask = rndMask[xBits]; + + for (;;) + { + random.NextBytes(b); + + // strip off any excess bits in the MSB + b[0] &= mask; + + // ensure the leading bit is 1 (to meet the strength requirement) + b[0] |= (byte)(1 << (7 - xBits)); + + // ensure the trailing bit is 1 (i.e. must be odd) + b[nBytes - 1] |= 1; + + this.magnitude = MakeMagnitude(b, 0, b.Length); + this.nBits = -1; + this.mQuote = -1L; + + if (certainty < 1) + break; + + if (CheckProbablePrime(certainty, random)) + break; + + if (bitLength > 32) + { + for (int rep = 0; rep < 10000; ++rep) + { + int n = 33 + random.Next(bitLength - 2); + this.magnitude[this.magnitude.Length - (n >> 5)] ^= (1 << (n & 31)); + this.magnitude[this.magnitude.Length - 1] ^= ((random.Next() + 1) << 1); + this.mQuote = -1L; + + if (CheckProbablePrime(certainty, random)) + return; + } + } + } + } + + public BigInteger Abs() + { + return sign >= 0 ? this : Negate(); + } + + /** + * return a = a + b - b preserved. + */ + private static int[] AddMagnitudes( + int[] a, + int[] b) + { + int tI = a.Length - 1; + int vI = b.Length - 1; + long m = 0; + + while (vI >= 0) + { + m += ((long)(uint)a[tI] + (long)(uint)b[vI--]); + a[tI--] = (int)m; + m = (long)((ulong)m >> 32); + } + + if (m != 0) + { + while (tI >= 0 && ++a[tI--] == 0) + { + } + } + + return a; + } + + public BigInteger Add( + BigInteger value) + { + if (this.sign == 0) + return value; + + if (this.sign != value.sign) + { + if (value.sign == 0) + return this; + + if (value.sign < 0) + return Subtract(value.Negate()); + + return value.Subtract(Negate()); + } + + return AddToMagnitude(value.magnitude); + } + + private BigInteger AddToMagnitude( + int[] magToAdd) + { + int[] big, small; + if (this.magnitude.Length < magToAdd.Length) + { + big = magToAdd; + small = this.magnitude; + } + else + { + big = this.magnitude; + small = magToAdd; + } + + // Conservatively avoid over-allocation when no overflow possible + uint limit = uint.MaxValue; + if (big.Length == small.Length) + limit -= (uint) small[0]; + + bool possibleOverflow = (uint) big[0] >= limit; + + int[] bigCopy; + if (possibleOverflow) + { + bigCopy = new int[big.Length + 1]; + big.CopyTo(bigCopy, 1); + } + else + { + bigCopy = (int[]) big.Clone(); + } + + bigCopy = AddMagnitudes(bigCopy, small); + + return new BigInteger(this.sign, bigCopy, possibleOverflow); + } + + public BigInteger And( + BigInteger value) + { + if (this.sign == 0 || value.sign == 0) + { + return Zero; + } + + int[] aMag = this.sign > 0 + ? this.magnitude + : Add(One).magnitude; + + int[] bMag = value.sign > 0 + ? value.magnitude + : value.Add(One).magnitude; + + bool resultNeg = sign < 0 && value.sign < 0; + int resultLength = System.Math.Max(aMag.Length, bMag.Length); + int[] resultMag = new int[resultLength]; + + int aStart = resultMag.Length - aMag.Length; + int bStart = resultMag.Length - bMag.Length; + + for (int i = 0; i < resultMag.Length; ++i) + { + int aWord = i >= aStart ? aMag[i - aStart] : 0; + int bWord = i >= bStart ? bMag[i - bStart] : 0; + + if (this.sign < 0) + { + aWord = ~aWord; + } + + if (value.sign < 0) + { + bWord = ~bWord; + } + + resultMag[i] = aWord & bWord; + + if (resultNeg) + { + resultMag[i] = ~resultMag[i]; + } + } + + BigInteger result = new BigInteger(1, resultMag, true); + + // TODO Optimise this case + if (resultNeg) + { + result = result.Not(); + } + + return result; + } + + public BigInteger AndNot( + BigInteger val) + { + return And(val.Not()); + } + + public int BitCount + { + get + { + if (nBits == -1) + { + if (sign < 0) + { + // TODO Optimise this case + nBits = Not().BitCount; + } + else + { + int sum = 0; + for (int i = 0; i < magnitude.Length; i++) + { + sum += bitCounts[(byte) magnitude[i]]; + sum += bitCounts[(byte)(magnitude[i] >> 8)]; + sum += bitCounts[(byte)(magnitude[i] >> 16)]; + sum += bitCounts[(byte)(magnitude[i] >> 24)]; + } + nBits = sum; + } + } + + return nBits; + } + } + + private readonly static byte[] bitCounts = + { + 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, + 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, + 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, + 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4, 3, 4, 4, 5, + 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, + 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, + 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, + 7, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, + 5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 4, 5, 5, 6, 5, 6, 6, 7, 5, + 6, 6, 7, 6, 7, 7, 8 + }; + + private int calcBitLength( + int indx, + int[] mag) + { + for (;;) + { + if (indx >= mag.Length) + return 0; + + if (mag[indx] != 0) + break; + + ++indx; + } + + // bit length for everything after the first int + int bitLength = 32 * ((mag.Length - indx) - 1); + + // and determine bitlength of first int + int firstMag = mag[indx]; + bitLength += BitLen(firstMag); + + // Check for negative powers of two + if (sign < 0 && ((firstMag & -firstMag) == firstMag)) + { + do + { + if (++indx >= mag.Length) + { + --bitLength; + break; + } + } + while (mag[indx] == 0); + } + + return bitLength; + } + + public int BitLength + { + get + { + if (nBitLength == -1) + { + nBitLength = sign == 0 + ? 0 + : calcBitLength(0, magnitude); + } + + return nBitLength; + } + } + + // + // BitLen(value) is the number of bits in value. + // + private static int BitLen( + int w) + { + // Binary search - decision tree (5 tests, rarely 6) + return (w < 1 << 15 ? (w < 1 << 7 + ? (w < 1 << 3 ? (w < 1 << 1 + ? (w < 1 << 0 ? (w < 0 ? 32 : 0) : 1) + : (w < 1 << 2 ? 2 : 3)) : (w < 1 << 5 + ? (w < 1 << 4 ? 4 : 5) + : (w < 1 << 6 ? 6 : 7))) + : (w < 1 << 11 + ? (w < 1 << 9 ? (w < 1 << 8 ? 8 : 9) : (w < 1 << 10 ? 10 : 11)) + : (w < 1 << 13 ? (w < 1 << 12 ? 12 : 13) : (w < 1 << 14 ? 14 : 15)))) : (w < 1 << 23 ? (w < 1 << 19 + ? (w < 1 << 17 ? (w < 1 << 16 ? 16 : 17) : (w < 1 << 18 ? 18 : 19)) + : (w < 1 << 21 ? (w < 1 << 20 ? 20 : 21) : (w < 1 << 22 ? 22 : 23))) : (w < 1 << 27 + ? (w < 1 << 25 ? (w < 1 << 24 ? 24 : 25) : (w < 1 << 26 ? 26 : 27)) + : (w < 1 << 29 ? (w < 1 << 28 ? 28 : 29) : (w < 1 << 30 ? 30 : 31))))); + } + +// private readonly static byte[] bitLengths = +// { +// 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, +// 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, +// 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, +// 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, +// 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, +// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, +// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, +// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, +// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, +// 8, 8, 8, 8, 8, 8, 8, 8 +// }; + + private bool QuickPow2Check() + { + return sign > 0 && nBits == 1; + } + + public int CompareTo( + object obj) + { + return CompareTo((BigInteger)obj); + } + + /** + * unsigned comparison on two arrays - note the arrays may + * start with leading zeros. + */ + private static int CompareTo( + int xIndx, + int[] x, + int yIndx, + int[] y) + { + while (xIndx != x.Length && x[xIndx] == 0) + { + xIndx++; + } + + while (yIndx != y.Length && y[yIndx] == 0) + { + yIndx++; + } + + return CompareNoLeadingZeroes(xIndx, x, yIndx, y); + } + + private static int CompareNoLeadingZeroes( + int xIndx, + int[] x, + int yIndx, + int[] y) + { + int diff = (x.Length - y.Length) - (xIndx - yIndx); + + if (diff != 0) + { + return diff < 0 ? -1 : 1; + } + + // lengths of magnitudes the same, test the magnitude values + + while (xIndx < x.Length) + { + uint v1 = (uint)x[xIndx++]; + uint v2 = (uint)y[yIndx++]; + + if (v1 != v2) + return v1 < v2 ? -1 : 1; + } + + return 0; + } + + public int CompareTo( + BigInteger value) + { + return sign < value.sign ? -1 + : sign > value.sign ? 1 + : sign == 0 ? 0 + : sign * CompareNoLeadingZeroes(0, magnitude, 0, value.magnitude); + } + + /** + * return z = x / y - done in place (z value preserved, x contains the + * remainder) + */ + private int[] Divide( + int[] x, + int[] y) + { + int xStart = 0; + while (xStart < x.Length && x[xStart] == 0) + { + ++xStart; + } + + int yStart = 0; + while (yStart < y.Length && y[yStart] == 0) + { + ++yStart; + } + + Debug.Assert(yStart < y.Length); + + int xyCmp = CompareNoLeadingZeroes(xStart, x, yStart, y); + int[] count; + + if (xyCmp > 0) + { + int yBitLength = calcBitLength(yStart, y); + int xBitLength = calcBitLength(xStart, x); + int shift = xBitLength - yBitLength; + + int[] iCount; + int iCountStart = 0; + + int[] c; + int cStart = 0; + int cBitLength = yBitLength; + if (shift > 0) + { +// iCount = ShiftLeft(One.magnitude, shift); + iCount = new int[(shift >> 5) + 1]; + iCount[0] = 1 << (shift % 32); + + c = ShiftLeft(y, shift); + cBitLength += shift; + } + else + { + iCount = new int[] { 1 }; + + int len = y.Length - yStart; + c = new int[len]; + Array.Copy(y, yStart, c, 0, len); + } + + count = new int[iCount.Length]; + + for (;;) + { + if (cBitLength < xBitLength + || CompareNoLeadingZeroes(xStart, x, cStart, c) >= 0) + { + Subtract(xStart, x, cStart, c); + AddMagnitudes(count, iCount); + + while (x[xStart] == 0) + { + if (++xStart == x.Length) + return count; + } + + //xBitLength = calcBitLength(xStart, x); + xBitLength = 32 * (x.Length - xStart - 1) + BitLen(x[xStart]); + + if (xBitLength <= yBitLength) + { + if (xBitLength < yBitLength) + return count; + + xyCmp = CompareNoLeadingZeroes(xStart, x, yStart, y); + + if (xyCmp <= 0) + break; + } + } + + shift = cBitLength - xBitLength; + + // NB: The case where c[cStart] is 1-bit is harmless + if (shift == 1) + { + uint firstC = (uint) c[cStart] >> 1; + uint firstX = (uint) x[xStart]; + if (firstC > firstX) + ++shift; + } + + if (shift < 2) + { + ShiftRightOneInPlace(cStart, c); + --cBitLength; + ShiftRightOneInPlace(iCountStart, iCount); + } + else + { + ShiftRightInPlace(cStart, c, shift); + cBitLength -= shift; + ShiftRightInPlace(iCountStart, iCount, shift); + } + + //cStart = c.Length - ((cBitLength + 31) / 32); + while (c[cStart] == 0) + { + ++cStart; + } + + while (iCount[iCountStart] == 0) + { + ++iCountStart; + } + } + } + else + { + count = new int[1]; + } + + if (xyCmp == 0) + { + AddMagnitudes(count, One.magnitude); + Array.Clear(x, xStart, x.Length - xStart); + } + + return count; + } + + public BigInteger Divide( + BigInteger val) + { + if (val.sign == 0) + throw new ArithmeticException("Division by zero error"); + + if (sign == 0) + return Zero; + + if (val.QuickPow2Check()) // val is power of two + { + BigInteger result = this.Abs().ShiftRight(val.Abs().BitLength - 1); + return val.sign == this.sign ? result : result.Negate(); + } + + int[] mag = (int[]) this.magnitude.Clone(); + + return new BigInteger(this.sign * val.sign, Divide(mag, val.magnitude), true); + } + + public BigInteger[] DivideAndRemainder( + BigInteger val) + { + if (val.sign == 0) + throw new ArithmeticException("Division by zero error"); + + BigInteger[] biggies = new BigInteger[2]; + + if (sign == 0) + { + biggies[0] = Zero; + biggies[1] = Zero; + } + else if (val.QuickPow2Check()) // val is power of two + { + int e = val.Abs().BitLength - 1; + BigInteger quotient = this.Abs().ShiftRight(e); + int[] remainder = this.LastNBits(e); + + biggies[0] = val.sign == this.sign ? quotient : quotient.Negate(); + biggies[1] = new BigInteger(this.sign, remainder, true); + } + else + { + int[] remainder = (int[]) this.magnitude.Clone(); + int[] quotient = Divide(remainder, val.magnitude); + + biggies[0] = new BigInteger(this.sign * val.sign, quotient, true); + biggies[1] = new BigInteger(this.sign, remainder, true); + } + + return biggies; + } + + public override bool Equals( + object obj) + { + if (obj == this) + return true; + + BigInteger biggie = obj as BigInteger; + if (biggie == null) + return false; + + if (biggie.sign != sign || biggie.magnitude.Length != magnitude.Length) + return false; + + for (int i = 0; i < magnitude.Length; i++) + { + if (biggie.magnitude[i] != magnitude[i]) + { + return false; + } + } + + return true; + } + + public BigInteger Gcd( + BigInteger value) + { + if (value.sign == 0) + return Abs(); + + if (sign == 0) + return value.Abs(); + + BigInteger r; + BigInteger u = this; + BigInteger v = value; + + while (v.sign != 0) + { + r = u.Mod(v); + u = v; + v = r; + } + + return u; + } + + public override int GetHashCode() + { + int hc = magnitude.Length; + if (magnitude.Length > 0) + { + hc ^= magnitude[0]; + + if (magnitude.Length > 1) + { + hc ^= magnitude[magnitude.Length - 1]; + } + } + + return sign < 0 ? ~hc : hc; + } + + // TODO Make public? + private BigInteger Inc() + { + if (this.sign == 0) + return One; + + if (this.sign < 0) + return new BigInteger(-1, doSubBigLil(this.magnitude, One.magnitude), true); + + return AddToMagnitude(One.magnitude); + } + + public int IntValue + { + get + { + return sign == 0 ? 0 + : sign > 0 ? magnitude[magnitude.Length - 1] + : -magnitude[magnitude.Length - 1]; + } + } + + /** + * return whether or not a BigInteger is probably prime with a + * probability of 1 - (1/2)**certainty. + * <p>From Knuth Vol 2, pg 395.</p> + */ + public bool IsProbablePrime( + int certainty) + { + if (certainty <= 0) + return true; + + BigInteger n = Abs(); + + if (!n.TestBit(0)) + return n.Equals(Two); + + if (n.Equals(One)) + return false; + + return n.CheckProbablePrime(certainty, RandomSource); + } + + private bool CheckProbablePrime( + int certainty, + Random random) + { + Debug.Assert(certainty > 0); + Debug.Assert(CompareTo(Two) > 0); + Debug.Assert(TestBit(0)); + + + // Try to reduce the penalty for really small numbers + int numLists = System.Math.Min(BitLength - 1, primeLists.Length); + + for (int i = 0; i < numLists; ++i) + { + int test = Remainder(primeProducts[i]); + + int[] primeList = primeLists[i]; + for (int j = 0; j < primeList.Length; ++j) + { + int prime = primeList[j]; + int qRem = test % prime; + if (qRem == 0) + { + // We may find small numbers in the list + return BitLength < 16 && IntValue == prime; + } + } + } + + + // TODO Special case for < 10^16 (RabinMiller fixed list) +// if (BitLength < 30) +// { +// RabinMiller against 2, 3, 5, 7, 11, 13, 23 is sufficient +// } + + + // TODO Is it worth trying to create a hybrid of these two? + return RabinMillerTest(certainty, random); +// return SolovayStrassenTest(certainty, random); + +// bool rbTest = RabinMillerTest(certainty, random); +// bool ssTest = SolovayStrassenTest(certainty, random); +// +// Debug.Assert(rbTest == ssTest); +// +// return rbTest; + } + + internal bool RabinMillerTest( + int certainty, + Random random) + { + Debug.Assert(certainty > 0); + Debug.Assert(BitLength > 2); + Debug.Assert(TestBit(0)); + + // let n = 1 + d . 2^s + BigInteger n = this; + BigInteger nMinusOne = n.Subtract(One); + int s = nMinusOne.GetLowestSetBit(); + BigInteger r = nMinusOne.ShiftRight(s); + + Debug.Assert(s >= 1); + + do + { + // TODO Make a method for random BigIntegers in range 0 < x < n) + // - Method can be optimized by only replacing examined bits at each trial + BigInteger a; + do + { + a = new BigInteger(n.BitLength, random); + } + while (a.CompareTo(One) <= 0 || a.CompareTo(nMinusOne) >= 0); + + BigInteger y = a.ModPow(r, n); + + if (!y.Equals(One)) + { + int j = 0; + while (!y.Equals(nMinusOne)) + { + if (++j == s) + return false; + + y = y.ModPow(Two, n); + + if (y.Equals(One)) + return false; + } + } + + certainty -= 2; // composites pass for only 1/4 possible 'a' + } + while (certainty > 0); + + return true; + } + +// private bool SolovayStrassenTest( +// int certainty, +// Random random) +// { +// Debug.Assert(certainty > 0); +// Debug.Assert(CompareTo(Two) > 0); +// Debug.Assert(TestBit(0)); +// +// BigInteger n = this; +// BigInteger nMinusOne = n.Subtract(One); +// BigInteger e = nMinusOne.ShiftRight(1); +// +// do +// { +// BigInteger a; +// do +// { +// a = new BigInteger(nBitLength, random); +// } +// // NB: Spec says 0 < x < n, but 1 is trivial +// while (a.CompareTo(One) <= 0 || a.CompareTo(n) >= 0); +// +// +// // TODO Check this is redundant given the way Jacobi() works? +//// if (!a.Gcd(n).Equals(One)) +//// return false; +// +// int x = Jacobi(a, n); +// +// if (x == 0) +// return false; +// +// BigInteger check = a.ModPow(e, n); +// +// if (x == 1 && !check.Equals(One)) +// return false; +// +// if (x == -1 && !check.Equals(nMinusOne)) +// return false; +// +// --certainty; +// } +// while (certainty > 0); +// +// return true; +// } +// +// private static int Jacobi( +// BigInteger a, +// BigInteger b) +// { +// Debug.Assert(a.sign >= 0); +// Debug.Assert(b.sign > 0); +// Debug.Assert(b.TestBit(0)); +// Debug.Assert(a.CompareTo(b) < 0); +// +// int totalS = 1; +// for (;;) +// { +// if (a.sign == 0) +// return 0; +// +// if (a.Equals(One)) +// break; +// +// int e = a.GetLowestSetBit(); +// +// int bLsw = b.magnitude[b.magnitude.Length - 1]; +// if ((e & 1) != 0 && ((bLsw & 7) == 3 || (bLsw & 7) == 5)) +// totalS = -totalS; +// +// // TODO Confirm this is faster than later a1.Equals(One) test +// if (a.BitLength == e + 1) +// break; +// BigInteger a1 = a.ShiftRight(e); +//// if (a1.Equals(One)) +//// break; +// +// int a1Lsw = a1.magnitude[a1.magnitude.Length - 1]; +// if ((bLsw & 3) == 3 && (a1Lsw & 3) == 3) +// totalS = -totalS; +// +//// a = b.Mod(a1); +// a = b.Remainder(a1); +// b = a1; +// } +// return totalS; +// } + + public long LongValue + { + get + { + if (sign == 0) + return 0; + + long v; + if (magnitude.Length > 1) + { + v = ((long)magnitude[magnitude.Length - 2] << 32) + | (magnitude[magnitude.Length - 1] & IMASK); + } + else + { + v = (magnitude[magnitude.Length - 1] & IMASK); + } + + return sign < 0 ? -v : v; + } + } + + public BigInteger Max( + BigInteger value) + { + return CompareTo(value) > 0 ? this : value; + } + + public BigInteger Min( + BigInteger value) + { + return CompareTo(value) < 0 ? this : value; + } + + public BigInteger Mod( + BigInteger m) + { + if (m.sign < 1) + throw new ArithmeticException("Modulus must be positive"); + + BigInteger biggie = Remainder(m); + + return (biggie.sign >= 0 ? biggie : biggie.Add(m)); + } + + public BigInteger ModInverse( + BigInteger m) + { + if (m.sign < 1) + throw new ArithmeticException("Modulus must be positive"); + + // TODO Too slow at the moment +// // "Fast Key Exchange with Elliptic Curve Systems" R.Schoeppel +// if (m.TestBit(0)) +// { +// //The Almost Inverse Algorithm +// int k = 0; +// BigInteger B = One, C = Zero, F = this, G = m, tmp; +// +// for (;;) +// { +// // While F is even, do F=F/u, C=C*u, k=k+1. +// int zeroes = F.GetLowestSetBit(); +// if (zeroes > 0) +// { +// F = F.ShiftRight(zeroes); +// C = C.ShiftLeft(zeroes); +// k += zeroes; +// } +// +// // If F = 1, then return B,k. +// if (F.Equals(One)) +// { +// BigInteger half = m.Add(One).ShiftRight(1); +// BigInteger halfK = half.ModPow(BigInteger.ValueOf(k), m); +// return B.Multiply(halfK).Mod(m); +// } +// +// if (F.CompareTo(G) < 0) +// { +// tmp = G; G = F; F = tmp; +// tmp = B; B = C; C = tmp; +// } +// +// F = F.Add(G); +// B = B.Add(C); +// } +// } + + BigInteger x; + BigInteger gcd = ExtEuclid(this.Mod(m), m, out x); + + if (!gcd.Equals(One)) + throw new ArithmeticException("Numbers not relatively prime."); + + if (x.sign < 0) + { + x = x.Add(m); + } + + return x; + } + + /** + * Calculate the numbers u1, u2, and u3 such that: + * + * u1 * a + u2 * b = u3 + * + * where u3 is the greatest common divider of a and b. + * a and b using the extended Euclid algorithm (refer p. 323 + * of The Art of Computer Programming vol 2, 2nd ed). + * This also seems to have the side effect of calculating + * some form of multiplicative inverse. + * + * @param a First number to calculate gcd for + * @param b Second number to calculate gcd for + * @param u1Out the return object for the u1 value + * @param u2Out the return object for the u2 value + * @return The greatest common divisor of a and b + */ + private static BigInteger ExtEuclid( + BigInteger a, + BigInteger b, + out BigInteger u1Out) + //BigInteger u2Out) + { + BigInteger u1 = One; + BigInteger u3 = a; + BigInteger v1 = Zero; + BigInteger v3 = b; + + while (v3.sign > 0) + { + BigInteger[] q = u3.DivideAndRemainder(v3); + + BigInteger tmp = v1.Multiply(q[0]); + BigInteger tn = u1.Subtract(tmp); + u1 = v1; + v1 = tn; + + u3 = v3; + v3 = q[1]; + } + + //if (u1Out != null) + //{ + // u1Out.sign = u1.sign; + // u1Out.magnitude = u1.magnitude; + //} + u1Out = u1; + + //if (u2Out != null) + //{ + // BigInteger tmp = u1.Multiply(a); + // tmp = u3.Subtract(tmp); + // BigInteger res = tmp.Divide(b); + // u2Out.sign = res.sign; + // u2Out.magnitude = res.magnitude; + //} + + return u3; + } + + private static void ZeroOut( + int[] x) + { + Array.Clear(x, 0, x.Length); + } + + public BigInteger ModPow( + BigInteger exponent, + BigInteger m) + { + if (m.sign < 1) + throw new ArithmeticException("Modulus must be positive"); + + if (m.Equals(One)) + return Zero; + + if (exponent.sign == 0) + return One; + + if (sign == 0) + return Zero; + + int[] zVal = null; + int[] yAccum = null; + int[] yVal; + + // Montgomery exponentiation is only possible if the modulus is odd, + // but AFAIK, this is always the case for crypto algo's + bool useMonty = ((m.magnitude[m.magnitude.Length - 1] & 1) == 1); + long mQ = 0; + if (useMonty) + { + mQ = m.GetMQuote(); + + // tmp = this * R mod m + BigInteger tmp = ShiftLeft(32 * m.magnitude.Length).Mod(m); + zVal = tmp.magnitude; + + useMonty = (zVal.Length <= m.magnitude.Length); + + if (useMonty) + { + yAccum = new int[m.magnitude.Length + 1]; + if (zVal.Length < m.magnitude.Length) + { + int[] longZ = new int[m.magnitude.Length]; + zVal.CopyTo(longZ, longZ.Length - zVal.Length); + zVal = longZ; + } + } + } + + if (!useMonty) + { + if (magnitude.Length <= m.magnitude.Length) + { + //zAccum = new int[m.magnitude.Length * 2]; + zVal = new int[m.magnitude.Length]; + magnitude.CopyTo(zVal, zVal.Length - magnitude.Length); + } + else + { + // + // in normal practice we'll never see this... + // + BigInteger tmp = Remainder(m); + + //zAccum = new int[m.magnitude.Length * 2]; + zVal = new int[m.magnitude.Length]; + tmp.magnitude.CopyTo(zVal, zVal.Length - tmp.magnitude.Length); + } + + yAccum = new int[m.magnitude.Length * 2]; + } + + yVal = new int[m.magnitude.Length]; + + // + // from LSW to MSW + // + for (int i = 0; i < exponent.magnitude.Length; i++) + { + int v = exponent.magnitude[i]; + int bits = 0; + + if (i == 0) + { + while (v > 0) + { + v <<= 1; + bits++; + } + + // + // first time in initialise y + // + zVal.CopyTo(yVal, 0); + + v <<= 1; + bits++; + } + + while (v != 0) + { + if (useMonty) + { + // Montgomery square algo doesn't exist, and a normal + // square followed by a Montgomery reduction proved to + // be almost as heavy as a Montgomery mulitply. + MultiplyMonty(yAccum, yVal, yVal, m.magnitude, mQ); + } + else + { + Square(yAccum, yVal); + Remainder(yAccum, m.magnitude); + Array.Copy(yAccum, yAccum.Length - yVal.Length, yVal, 0, yVal.Length); + ZeroOut(yAccum); + } + bits++; + + if (v < 0) + { + if (useMonty) + { + MultiplyMonty(yAccum, yVal, zVal, m.magnitude, mQ); + } + else + { + Multiply(yAccum, yVal, zVal); + Remainder(yAccum, m.magnitude); + Array.Copy(yAccum, yAccum.Length - yVal.Length, yVal, 0, + yVal.Length); + ZeroOut(yAccum); + } + } + + v <<= 1; + } + + while (bits < 32) + { + if (useMonty) + { + MultiplyMonty(yAccum, yVal, yVal, m.magnitude, mQ); + } + else + { + Square(yAccum, yVal); + Remainder(yAccum, m.magnitude); + Array.Copy(yAccum, yAccum.Length - yVal.Length, yVal, 0, yVal.Length); + ZeroOut(yAccum); + } + bits++; + } + } + + if (useMonty) + { + // Return y * R^(-1) mod m by doing y * 1 * R^(-1) mod m + ZeroOut(zVal); + zVal[zVal.Length - 1] = 1; + MultiplyMonty(yAccum, yVal, zVal, m.magnitude, mQ); + } + + BigInteger result = new BigInteger(1, yVal, true); + + return exponent.sign > 0 + ? result + : result.ModInverse(m); + } + + /** + * return w with w = x * x - w is assumed to have enough space. + */ + private static int[] Square( + int[] w, + int[] x) + { + // Note: this method allows w to be only (2 * x.Length - 1) words if result will fit +// if (w.Length != 2 * x.Length) +// throw new ArgumentException("no I don't think so..."); + + ulong u1, u2, c; + + int wBase = w.Length - 1; + + for (int i = x.Length - 1; i != 0; i--) + { + ulong v = (ulong)(uint) x[i]; + + u1 = v * v; + u2 = u1 >> 32; + u1 = (uint) u1; + + u1 += (ulong)(uint) w[wBase]; + + w[wBase] = (int)(uint) u1; + c = u2 + (u1 >> 32); + + for (int j = i - 1; j >= 0; j--) + { + --wBase; + u1 = v * (ulong)(uint) x[j]; + u2 = u1 >> 31; // multiply by 2! + u1 = (uint)(u1 << 1); // multiply by 2! + u1 += c + (ulong)(uint) w[wBase]; + + w[wBase] = (int)(uint) u1; + c = u2 + (u1 >> 32); + } + + c += (ulong)(uint) w[--wBase]; + w[wBase] = (int)(uint) c; + + if (--wBase >= 0) + { + w[wBase] = (int)(uint)(c >> 32); + } + else + { + Debug.Assert((uint)(c >> 32) == 0); + } + wBase += i; + } + + u1 = (ulong)(uint) x[0]; + u1 = u1 * u1; + u2 = u1 >> 32; + u1 = u1 & IMASK; + + u1 += (ulong)(uint) w[wBase]; + + w[wBase] = (int)(uint) u1; + if (--wBase >= 0) + { + w[wBase] = (int)(uint)(u2 + (u1 >> 32) + (ulong)(uint) w[wBase]); + } + else + { + Debug.Assert((uint)(u2 + (u1 >> 32)) == 0); + } + + return w; + } + + /** + * return x with x = y * z - x is assumed to have enough space. + */ + private static int[] Multiply( + int[] x, + int[] y, + int[] z) + { + int i = z.Length; + + if (i < 1) + return x; + + int xBase = x.Length - y.Length; + + do + { + long a = z[--i] & IMASK; + long val = 0; + + if (a != 0) + { + for (int j = y.Length - 1; j >= 0; j--) + { + val += a * (y[j] & IMASK) + (x[xBase + j] & IMASK); + + x[xBase + j] = (int)val; + + val = (long)((ulong)val >> 32); + } + } + + --xBase; + + if (xBase >= 0) + { + x[xBase] = (int)val; + } + else + { + Debug.Assert(val == 0); + } + } + while (i > 0); + + return x; + } + + private static long FastExtEuclid( + long a, + long b, + long[] uOut) + { + long u1 = 1; + long u3 = a; + long v1 = 0; + long v3 = b; + + while (v3 > 0) + { + long q, tn; + + q = u3 / v3; + + tn = u1 - (v1 * q); + u1 = v1; + v1 = tn; + + tn = u3 - (v3 * q); + u3 = v3; + v3 = tn; + } + + uOut[0] = u1; + uOut[1] = (u3 - (u1 * a)) / b; + + return u3; + } + + private static long FastModInverse( + long v, + long m) + { + if (m < 1) + throw new ArithmeticException("Modulus must be positive"); + + long[] x = new long[2]; + long gcd = FastExtEuclid(v, m, x); + + if (gcd != 1) + throw new ArithmeticException("Numbers not relatively prime."); + + if (x[0] < 0) + { + x[0] += m; + } + + return x[0]; + } + +// private static BigInteger MQuoteB = One.ShiftLeft(32); +// private static BigInteger MQuoteBSub1 = MQuoteB.Subtract(One); + + /** + * Calculate mQuote = -m^(-1) mod b with b = 2^32 (32 = word size) + */ + private long GetMQuote() + { + Debug.Assert(this.sign > 0); + + if (mQuote != -1) + { + return mQuote; // already calculated + } + + if (magnitude.Length == 0 || (magnitude[magnitude.Length - 1] & 1) == 0) + { + return -1; // not for even numbers + } + + long v = (((~this.magnitude[this.magnitude.Length - 1]) | 1) & 0xffffffffL); + mQuote = FastModInverse(v, 0x100000000L); + + return mQuote; + } + + /** + * Montgomery multiplication: a = x * y * R^(-1) mod m + * <br/> + * Based algorithm 14.36 of Handbook of Applied Cryptography. + * <br/> + * <li> m, x, y should have length n </li> + * <li> a should have length (n + 1) </li> + * <li> b = 2^32, R = b^n </li> + * <br/> + * The result is put in x + * <br/> + * NOTE: the indices of x, y, m, a different in HAC and in Java + */ + private static void MultiplyMonty( + int[] a, + int[] x, + int[] y, + int[] m, + long mQuote) + // mQuote = -m^(-1) mod b + { + if (m.Length == 1) + { + x[0] = (int)MultiplyMontyNIsOne((uint)x[0], (uint)y[0], (uint)m[0], (ulong)mQuote); + return; + } + + int n = m.Length; + int nMinus1 = n - 1; + long y_0 = y[nMinus1] & IMASK; + + // 1. a = 0 (Notation: a = (a_{n} a_{n-1} ... a_{0})_{b} ) + Array.Clear(a, 0, n + 1); + + // 2. for i from 0 to (n - 1) do the following: + for (int i = n; i > 0; i--) + { + long x_i = x[i - 1] & IMASK; + + // 2.1 u = ((a[0] + (x[i] * y[0]) * mQuote) mod b + long u = ((((a[n] & IMASK) + ((x_i * y_0) & IMASK)) & IMASK) * mQuote) & IMASK; + + // 2.2 a = (a + x_i * y + u * m) / b + long prod1 = x_i * y_0; + long prod2 = u * (m[nMinus1] & IMASK); + long tmp = (a[n] & IMASK) + (prod1 & IMASK) + (prod2 & IMASK); + long carry = (long)((ulong)prod1 >> 32) + (long)((ulong)prod2 >> 32) + (long)((ulong)tmp >> 32); + for (int j = nMinus1; j > 0; j--) + { + prod1 = x_i * (y[j - 1] & IMASK); + prod2 = u * (m[j - 1] & IMASK); + tmp = (a[j] & IMASK) + (prod1 & IMASK) + (prod2 & IMASK) + (carry & IMASK); + carry = (long)((ulong)carry >> 32) + (long)((ulong)prod1 >> 32) + + (long)((ulong)prod2 >> 32) + (long)((ulong)tmp >> 32); + a[j + 1] = (int)tmp; // division by b + } + carry += (a[0] & IMASK); + a[1] = (int)carry; + a[0] = (int)((ulong)carry >> 32); // OJO!!!!! + } + + // 3. if x >= m the x = x - m + if (CompareTo(0, a, 0, m) >= 0) + { + Subtract(0, a, 0, m); + } + + // put the result in x + Array.Copy(a, 1, x, 0, n); + } + + private static uint MultiplyMontyNIsOne( + uint x, + uint y, + uint m, + ulong mQuote) + { + ulong um = m; + ulong prod1 = (ulong)x * (ulong)y; + ulong u = (prod1 * mQuote) & UIMASK; + ulong prod2 = u * um; + ulong tmp = (prod1 & UIMASK) + (prod2 & UIMASK); + ulong carry = (prod1 >> 32) + (prod2 >> 32) + (tmp >> 32); + + if (carry > um) + { + carry -= um; + } + + return (uint)(carry & UIMASK); + } + + public BigInteger Multiply( + BigInteger val) + { + if (sign == 0 || val.sign == 0) + return Zero; + + if (val.QuickPow2Check()) // val is power of two + { + BigInteger result = this.ShiftLeft(val.Abs().BitLength - 1); + return val.sign > 0 ? result : result.Negate(); + } + + if (this.QuickPow2Check()) // this is power of two + { + BigInteger result = val.ShiftLeft(this.Abs().BitLength - 1); + return this.sign > 0 ? result : result.Negate(); + } + + int resLength = (this.BitLength + val.BitLength) / BitsPerInt + 1; + int[] res = new int[resLength]; + + if (val == this) + { + Square(res, this.magnitude); + } + else + { + Multiply(res, this.magnitude, val.magnitude); + } + + return new BigInteger(sign * val.sign, res, true); + } + + public BigInteger Negate() + { + if (sign == 0) + return this; + + return new BigInteger(-sign, magnitude, false); + } + + public BigInteger NextProbablePrime() + { + if (sign < 0) + throw new ArithmeticException("Cannot be called on value < 0"); + + if (CompareTo(Two) < 0) + return Two; + + BigInteger n = Inc().SetBit(0); + + while (!n.CheckProbablePrime(100, RandomSource)) + { + n = n.Add(Two); + } + + return n; + } + + public BigInteger Not() + { + return Inc().Negate(); + } + + public BigInteger Pow(int exp) + { + if (exp < 0) + { + throw new ArithmeticException("Negative exponent"); + } + + if (exp == 0) + { + return One; + } + + if (sign == 0 || Equals(One)) + { + return this; + } + + BigInteger y = One; + BigInteger z = this; + + for (;;) + { + if ((exp & 0x1) == 1) + { + y = y.Multiply(z); + } + exp >>= 1; + if (exp == 0) break; + z = z.Multiply(z); + } + + return y; + } + + public static BigInteger ProbablePrime( + int bitLength, + Random random) + { + return new BigInteger(bitLength, 100, random); + } + + private int Remainder( + int m) + { + Debug.Assert(m > 0); + + long acc = 0; + for (int pos = 0; pos < magnitude.Length; ++pos) + { + long posVal = (uint) magnitude[pos]; + acc = (acc << 32 | posVal) % m; + } + + return (int) acc; + } + + /** + * return x = x % y - done in place (y value preserved) + */ + private int[] Remainder( + int[] x, + int[] y) + { + int xStart = 0; + while (xStart < x.Length && x[xStart] == 0) + { + ++xStart; + } + + int yStart = 0; + while (yStart < y.Length && y[yStart] == 0) + { + ++yStart; + } + + Debug.Assert(yStart < y.Length); + + int xyCmp = CompareNoLeadingZeroes(xStart, x, yStart, y); + + if (xyCmp > 0) + { + int yBitLength = calcBitLength(yStart, y); + int xBitLength = calcBitLength(xStart, x); + int shift = xBitLength - yBitLength; + + int[] c; + int cStart = 0; + int cBitLength = yBitLength; + if (shift > 0) + { + c = ShiftLeft(y, shift); + cBitLength += shift; + Debug.Assert(c[0] != 0); + } + else + { + int len = y.Length - yStart; + c = new int[len]; + Array.Copy(y, yStart, c, 0, len); + } + + for (;;) + { + if (cBitLength < xBitLength + || CompareNoLeadingZeroes(xStart, x, cStart, c) >= 0) + { + Subtract(xStart, x, cStart, c); + + while (x[xStart] == 0) + { + if (++xStart == x.Length) + return x; + } + + //xBitLength = calcBitLength(xStart, x); + xBitLength = 32 * (x.Length - xStart - 1) + BitLen(x[xStart]); + + if (xBitLength <= yBitLength) + { + if (xBitLength < yBitLength) + return x; + + xyCmp = CompareNoLeadingZeroes(xStart, x, yStart, y); + + if (xyCmp <= 0) + break; + } + } + + shift = cBitLength - xBitLength; + + // NB: The case where c[cStart] is 1-bit is harmless + if (shift == 1) + { + uint firstC = (uint) c[cStart] >> 1; + uint firstX = (uint) x[xStart]; + if (firstC > firstX) + ++shift; + } + + if (shift < 2) + { + ShiftRightOneInPlace(cStart, c); + --cBitLength; + } + else + { + ShiftRightInPlace(cStart, c, shift); + cBitLength -= shift; + } + + //cStart = c.Length - ((cBitLength + 31) / 32); + while (c[cStart] == 0) + { + ++cStart; + } + } + } + + if (xyCmp == 0) + { + Array.Clear(x, xStart, x.Length - xStart); + } + + return x; + } + + public BigInteger Remainder( + BigInteger n) + { + if (n.sign == 0) + throw new ArithmeticException("Division by zero error"); + + if (this.sign == 0) + return Zero; + + // For small values, use fast remainder method + if (n.magnitude.Length == 1) + { + int val = n.magnitude[0]; + + if (val > 0) + { + if (val == 1) + return Zero; + + // TODO Make this func work on uint, and handle val == 1? + int rem = Remainder(val); + + return rem == 0 + ? Zero + : new BigInteger(sign, new int[]{ rem }, false); + } + } + + if (CompareNoLeadingZeroes(0, magnitude, 0, n.magnitude) < 0) + return this; + + int[] result; + if (n.QuickPow2Check()) // n is power of two + { + // TODO Move before small values branch above? + result = LastNBits(n.Abs().BitLength - 1); + } + else + { + result = (int[]) this.magnitude.Clone(); + result = Remainder(result, n.magnitude); + } + + return new BigInteger(sign, result, true); + } + + private int[] LastNBits( + int n) + { + if (n < 1) + return ZeroMagnitude; + + int numWords = (n + BitsPerInt - 1) / BitsPerInt; + numWords = System.Math.Min(numWords, this.magnitude.Length); + int[] result = new int[numWords]; + + Array.Copy(this.magnitude, this.magnitude.Length - numWords, result, 0, numWords); + + int hiBits = n % 32; + if (hiBits != 0) + { + result[0] &= ~(-1 << hiBits); + } + + return result; + } + + /** + * do a left shift - this returns a new array. + */ + private static int[] ShiftLeft( + int[] mag, + int n) + { + int nInts = (int)((uint)n >> 5); + int nBits = n & 0x1f; + int magLen = mag.Length; + int[] newMag; + + if (nBits == 0) + { + newMag = new int[magLen + nInts]; + mag.CopyTo(newMag, 0); + } + else + { + int i = 0; + int nBits2 = 32 - nBits; + int highBits = (int)((uint)mag[0] >> nBits2); + + if (highBits != 0) + { + newMag = new int[magLen + nInts + 1]; + newMag[i++] = highBits; + } + else + { + newMag = new int[magLen + nInts]; + } + + int m = mag[0]; + for (int j = 0; j < magLen - 1; j++) + { + int next = mag[j + 1]; + + newMag[i++] = (m << nBits) | (int)((uint)next >> nBits2); + m = next; + } + + newMag[i] = mag[magLen - 1] << nBits; + } + + return newMag; + } + + public BigInteger ShiftLeft( + int n) + { + if (sign == 0 || magnitude.Length == 0) + return Zero; + + if (n == 0) + return this; + + if (n < 0) + return ShiftRight(-n); + + BigInteger result = new BigInteger(sign, ShiftLeft(magnitude, n), true); + + if (this.nBits != -1) + { + result.nBits = sign > 0 + ? this.nBits + : this.nBits + n; + } + + if (this.nBitLength != -1) + { + result.nBitLength = this.nBitLength + n; + } + + return result; + } + + /** + * do a right shift - this does it in place. + */ + private static void ShiftRightInPlace( + int start, + int[] mag, + int n) + { + int nInts = (int)((uint)n >> 5) + start; + int nBits = n & 0x1f; + int magEnd = mag.Length - 1; + + if (nInts != start) + { + int delta = (nInts - start); + + for (int i = magEnd; i >= nInts; i--) + { + mag[i] = mag[i - delta]; + } + for (int i = nInts - 1; i >= start; i--) + { + mag[i] = 0; + } + } + + if (nBits != 0) + { + int nBits2 = 32 - nBits; + int m = mag[magEnd]; + + for (int i = magEnd; i > nInts; --i) + { + int next = mag[i - 1]; + + mag[i] = (int)((uint)m >> nBits) | (next << nBits2); + m = next; + } + + mag[nInts] = (int)((uint)mag[nInts] >> nBits); + } + } + + /** + * do a right shift by one - this does it in place. + */ + private static void ShiftRightOneInPlace( + int start, + int[] mag) + { + int i = mag.Length; + int m = mag[i - 1]; + + while (--i > start) + { + int next = mag[i - 1]; + mag[i] = ((int)((uint)m >> 1)) | (next << 31); + m = next; + } + + mag[start] = (int)((uint)mag[start] >> 1); + } + + public BigInteger ShiftRight( + int n) + { + if (n == 0) + return this; + + if (n < 0) + return ShiftLeft(-n); + + if (n >= BitLength) + return (this.sign < 0 ? One.Negate() : Zero); + +// int[] res = (int[]) this.magnitude.Clone(); +// +// ShiftRightInPlace(0, res, n); +// +// return new BigInteger(this.sign, res, true); + + int resultLength = (BitLength - n + 31) >> 5; + int[] res = new int[resultLength]; + + int numInts = n >> 5; + int numBits = n & 31; + + if (numBits == 0) + { + Array.Copy(this.magnitude, 0, res, 0, res.Length); + } + else + { + int numBits2 = 32 - numBits; + + int magPos = this.magnitude.Length - 1 - numInts; + for (int i = resultLength - 1; i >= 0; --i) + { + res[i] = (int)((uint) this.magnitude[magPos--] >> numBits); + + if (magPos >= 0) + { + res[i] |= this.magnitude[magPos] << numBits2; + } + } + } + + Debug.Assert(res[0] != 0); + + return new BigInteger(this.sign, res, false); + } + + public int SignValue + { + get { return sign; } + } + + /** + * returns x = x - y - we assume x is >= y + */ + private static int[] Subtract( + int xStart, + int[] x, + int yStart, + int[] y) + { + Debug.Assert(yStart < y.Length); + Debug.Assert(x.Length - xStart >= y.Length - yStart); + + int iT = x.Length; + int iV = y.Length; + long m; + int borrow = 0; + + do + { + m = (x[--iT] & IMASK) - (y[--iV] & IMASK) + borrow; + x[iT] = (int) m; + +// borrow = (m < 0) ? -1 : 0; + borrow = (int)(m >> 63); + } + while (iV > yStart); + + if (borrow != 0) + { + while (--x[--iT] == -1) + { + } + } + + return x; + } + + public BigInteger Subtract( + BigInteger n) + { + if (n.sign == 0) + return this; + + if (this.sign == 0) + return n.Negate(); + + if (this.sign != n.sign) + return Add(n.Negate()); + + int compare = CompareNoLeadingZeroes(0, magnitude, 0, n.magnitude); + if (compare == 0) + return Zero; + + BigInteger bigun, lilun; + if (compare < 0) + { + bigun = n; + lilun = this; + } + else + { + bigun = this; + lilun = n; + } + + return new BigInteger(this.sign * compare, doSubBigLil(bigun.magnitude, lilun.magnitude), true); + } + + private static int[] doSubBigLil( + int[] bigMag, + int[] lilMag) + { + int[] res = (int[]) bigMag.Clone(); + + return Subtract(0, res, 0, lilMag); + } + + public byte[] ToByteArray() + { + return ToByteArray(false); + } + + public byte[] ToByteArrayUnsigned() + { + return ToByteArray(true); + } + + private byte[] ToByteArray( + bool unsigned) + { + if (sign == 0) + return unsigned ? ZeroEncoding : new byte[1]; + + int nBits = (unsigned && sign > 0) + ? BitLength + : BitLength + 1; + + int nBytes = GetByteLength(nBits); + byte[] bytes = new byte[nBytes]; + + int magIndex = magnitude.Length; + int bytesIndex = bytes.Length; + + if (sign > 0) + { + while (magIndex > 1) + { + uint mag = (uint) magnitude[--magIndex]; + bytes[--bytesIndex] = (byte) mag; + bytes[--bytesIndex] = (byte)(mag >> 8); + bytes[--bytesIndex] = (byte)(mag >> 16); + bytes[--bytesIndex] = (byte)(mag >> 24); + } + + uint lastMag = (uint) magnitude[0]; + while (lastMag > byte.MaxValue) + { + bytes[--bytesIndex] = (byte) lastMag; + lastMag >>= 8; + } + + bytes[--bytesIndex] = (byte) lastMag; + } + else // sign < 0 + { + bool carry = true; + + while (magIndex > 1) + { + uint mag = ~((uint) magnitude[--magIndex]); + + if (carry) + { + carry = (++mag == uint.MinValue); + } + + bytes[--bytesIndex] = (byte) mag; + bytes[--bytesIndex] = (byte)(mag >> 8); + bytes[--bytesIndex] = (byte)(mag >> 16); + bytes[--bytesIndex] = (byte)(mag >> 24); + } + + uint lastMag = (uint) magnitude[0]; + + if (carry) + { + // Never wraps because magnitude[0] != 0 + --lastMag; + } + + while (lastMag > byte.MaxValue) + { + bytes[--bytesIndex] = (byte) ~lastMag; + lastMag >>= 8; + } + + bytes[--bytesIndex] = (byte) ~lastMag; + + if (bytesIndex > 0) + { + bytes[--bytesIndex] = byte.MaxValue; + } + } + + return bytes; + } + + public override string ToString() + { + return ToString(10); + } + + public string ToString( + int radix) + { + // TODO Make this method work for other radices (ideally 2 <= radix <= 16) + + switch (radix) + { + case 2: + case 10: + case 16: + break; + default: + throw new FormatException("Only bases 2, 10, 16 are allowed"); + } + + // NB: Can only happen to internally managed instances + if (magnitude == null) + return "null"; + + if (sign == 0) + return "0"; + + Debug.Assert(magnitude.Length > 0); + + StringBuilder sb = new StringBuilder(); + + if (radix == 16) + { + sb.Append(magnitude[0].ToString("x")); + + for (int i = 1; i < magnitude.Length; i++) + { + sb.Append(magnitude[i].ToString("x8")); + } + } + else if (radix == 2) + { + sb.Append('1'); + + for (int i = BitLength - 2; i >= 0; --i) + { + sb.Append(TestBit(i) ? '1' : '0'); + } + } + else + { + // This is algorithm 1a from chapter 4.4 in Seminumerical Algorithms, slow but it works + IList S = Platform.CreateArrayList(); + BigInteger bs = ValueOf(radix); + + // The sign is handled separatly. + // Notice however that for this to work, radix 16 _MUST_ be a special case, + // unless we want to enter a recursion well. In their infinite wisdom, why did not + // the Sun engineers made a c'tor for BigIntegers taking a BigInteger as parameter? + // (Answer: Becuase Sun's BigIntger is clonable, something bouncycastle's isn't.) +// BigInteger u = new BigInteger(Abs().ToString(16), 16); + BigInteger u = this.Abs(); + BigInteger b; + + while (u.sign != 0) + { + b = u.Mod(bs); + if (b.sign == 0) + { + S.Add("0"); + } + else + { + // see how to interact with different bases + S.Add(b.magnitude[0].ToString("d")); + } + u = u.Divide(bs); + } + + // Then pop the stack + for (int i = S.Count - 1; i >= 0; --i) + { + sb.Append((string)S[i]); + } + } + + string s = sb.ToString(); + + Debug.Assert(s.Length > 0); + + // Strip leading zeros. (We know this number is not all zeroes though) + if (s[0] == '0') + { + int nonZeroPos = 0; + while (s[++nonZeroPos] == '0') {} + + s = s.Substring(nonZeroPos); + } + + if (sign == -1) + { + s = "-" + s; + } + + return s; + } + + private static BigInteger createUValueOf( + ulong value) + { + int msw = (int)(value >> 32); + int lsw = (int)value; + + if (msw != 0) + return new BigInteger(1, new int[] { msw, lsw }, false); + + if (lsw != 0) + { + BigInteger n = new BigInteger(1, new int[] { lsw }, false); + // Check for a power of two + if ((lsw & -lsw) == lsw) + { + n.nBits = 1; + } + return n; + } + + return Zero; + } + + private static BigInteger createValueOf( + long value) + { + if (value < 0) + { + if (value == long.MinValue) + return createValueOf(~value).Not(); + + return createValueOf(-value).Negate(); + } + + return createUValueOf((ulong)value); + +// // store value into a byte array +// byte[] b = new byte[8]; +// for (int i = 0; i < 8; i++) +// { +// b[7 - i] = (byte)value; +// value >>= 8; +// } +// +// return new BigInteger(b); + } + + public static BigInteger ValueOf( + long value) + { + switch (value) + { + case 0: + return Zero; + case 1: + return One; + case 2: + return Two; + case 3: + return Three; + case 10: + return Ten; + } + + return createValueOf(value); + } + + public int GetLowestSetBit() + { + if (this.sign == 0) + return -1; + + int w = magnitude.Length; + + while (--w > 0) + { + if (magnitude[w] != 0) + break; + } + + int word = (int) magnitude[w]; + Debug.Assert(word != 0); + + int b = (word & 0x0000FFFF) == 0 + ? (word & 0x00FF0000) == 0 + ? 7 + : 15 + : (word & 0x000000FF) == 0 + ? 23 + : 31; + + while (b > 0) + { + if ((word << b) == int.MinValue) + break; + + b--; + } + + return ((magnitude.Length - w) * 32 - (b + 1)); + } + + public bool TestBit( + int n) + { + if (n < 0) + throw new ArithmeticException("Bit position must not be negative"); + + if (sign < 0) + return !Not().TestBit(n); + + int wordNum = n / 32; + if (wordNum >= magnitude.Length) + return false; + + int word = magnitude[magnitude.Length - 1 - wordNum]; + return ((word >> (n % 32)) & 1) > 0; + } + + public BigInteger Or( + BigInteger value) + { + if (this.sign == 0) + return value; + + if (value.sign == 0) + return this; + + int[] aMag = this.sign > 0 + ? this.magnitude + : Add(One).magnitude; + + int[] bMag = value.sign > 0 + ? value.magnitude + : value.Add(One).magnitude; + + bool resultNeg = sign < 0 || value.sign < 0; + int resultLength = System.Math.Max(aMag.Length, bMag.Length); + int[] resultMag = new int[resultLength]; + + int aStart = resultMag.Length - aMag.Length; + int bStart = resultMag.Length - bMag.Length; + + for (int i = 0; i < resultMag.Length; ++i) + { + int aWord = i >= aStart ? aMag[i - aStart] : 0; + int bWord = i >= bStart ? bMag[i - bStart] : 0; + + if (this.sign < 0) + { + aWord = ~aWord; + } + + if (value.sign < 0) + { + bWord = ~bWord; + } + + resultMag[i] = aWord | bWord; + + if (resultNeg) + { + resultMag[i] = ~resultMag[i]; + } + } + + BigInteger result = new BigInteger(1, resultMag, true); + + // TODO Optimise this case + if (resultNeg) + { + result = result.Not(); + } + + return result; + } + + public BigInteger Xor( + BigInteger value) + { + if (this.sign == 0) + return value; + + if (value.sign == 0) + return this; + + int[] aMag = this.sign > 0 + ? this.magnitude + : Add(One).magnitude; + + int[] bMag = value.sign > 0 + ? value.magnitude + : value.Add(One).magnitude; + + // TODO Can just replace with sign != value.sign? + bool resultNeg = (sign < 0 && value.sign >= 0) || (sign >= 0 && value.sign < 0); + int resultLength = System.Math.Max(aMag.Length, bMag.Length); + int[] resultMag = new int[resultLength]; + + int aStart = resultMag.Length - aMag.Length; + int bStart = resultMag.Length - bMag.Length; + + for (int i = 0; i < resultMag.Length; ++i) + { + int aWord = i >= aStart ? aMag[i - aStart] : 0; + int bWord = i >= bStart ? bMag[i - bStart] : 0; + + if (this.sign < 0) + { + aWord = ~aWord; + } + + if (value.sign < 0) + { + bWord = ~bWord; + } + + resultMag[i] = aWord ^ bWord; + + if (resultNeg) + { + resultMag[i] = ~resultMag[i]; + } + } + + BigInteger result = new BigInteger(1, resultMag, true); + + // TODO Optimise this case + if (resultNeg) + { + result = result.Not(); + } + + return result; + } + + public BigInteger SetBit( + int n) + { + if (n < 0) + throw new ArithmeticException("Bit address less than zero"); + + if (TestBit(n)) + return this; + + // TODO Handle negative values and zero + if (sign > 0 && n < (BitLength - 1)) + return FlipExistingBit(n); + + return Or(One.ShiftLeft(n)); + } + + public BigInteger ClearBit( + int n) + { + if (n < 0) + throw new ArithmeticException("Bit address less than zero"); + + if (!TestBit(n)) + return this; + + // TODO Handle negative values + if (sign > 0 && n < (BitLength - 1)) + return FlipExistingBit(n); + + return AndNot(One.ShiftLeft(n)); + } + + public BigInteger FlipBit( + int n) + { + if (n < 0) + throw new ArithmeticException("Bit address less than zero"); + + // TODO Handle negative values and zero + if (sign > 0 && n < (BitLength - 1)) + return FlipExistingBit(n); + + return Xor(One.ShiftLeft(n)); + } + + private BigInteger FlipExistingBit( + int n) + { + Debug.Assert(sign > 0); + Debug.Assert(n >= 0); + Debug.Assert(n < BitLength - 1); + + int[] mag = (int[]) this.magnitude.Clone(); + mag[mag.Length - 1 - (n >> 5)] ^= (1 << (n & 31)); // Flip bit + //mag[mag.Length - 1 - (n / 32)] ^= (1 << (n % 32)); + return new BigInteger(this.sign, mag, false); + } + } +} |