diff options
| -rw-r--r-- | crypto/src/math/BigInteger.cs | 112 |
1 files changed, 33 insertions, 79 deletions
diff --git a/crypto/src/math/BigInteger.cs b/crypto/src/math/BigInteger.cs index d84680de5..a98955779 100644 --- a/crypto/src/math/BigInteger.cs +++ b/crypto/src/math/BigInteger.cs @@ -488,7 +488,7 @@ namespace Org.BouncyCastle.Math if ((sbyte)bytes[offset] >= 0) { // strip leading zero bytes and return magnitude bytes - this.magnitude = MakeMagnitude(bytes, offset, length); + this.magnitude = MakeMagnitudeBE(bytes, offset, length); this.sign = this.magnitude.Length > 0 ? 1 : 0; return; } @@ -534,115 +534,69 @@ namespace Org.BouncyCastle.Math inverse[index]++; - this.magnitude = MakeMagnitude(inverse); + this.magnitude = MakeMagnitudeBE(inverse); } - private static uint[] MakeMagnitude(byte[] bytes) + private static uint[] MakeMagnitudeBE(byte[] bytes) { - return MakeMagnitude(bytes, 0, bytes.Length); + return MakeMagnitudeBE(bytes, 0, bytes.Length); } - private static uint[] MakeMagnitude(byte[] bytes, int offset, int length) + private static uint[] MakeMagnitudeBE(byte[] bytes, int offset, int length) { #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER - return MakeMagnitude(bytes.AsSpan(offset, length)); + return MakeMagnitudeBE(bytes.AsSpan(offset, length)); #else int end = offset + length; // strip leading zeros - int firstSignificant; - for (firstSignificant = offset; firstSignificant < end && bytes[firstSignificant] == 0; firstSignificant++) + int start; + for (start = offset; start < end && bytes[start] == 0; start++) { } - if (firstSignificant >= end) + int nBytes = end - start; + if (nBytes <= 0) return ZeroMagnitude; - int nInts = (end - firstSignificant + 3) / BytesPerInt; - int bCount = (end - firstSignificant) % BytesPerInt; - if (bCount == 0) - { - bCount = BytesPerInt; - } - - if (nInts < 1) - return ZeroMagnitude; + int nInts = (nBytes + BytesPerInt - 1) / BytesPerInt; + Debug.Assert(nInts > 0); - uint[] mag = new uint[nInts]; + uint[] magnitude = new uint[nInts]; - uint v = 0U; - int magnitudeIndex = 0; - for (int i = firstSignificant; i < end; ++i) - { - v <<= 8; - v |= bytes[i]; - bCount--; - if (bCount <= 0) - { - mag[magnitudeIndex] = v; - magnitudeIndex++; - bCount = BytesPerInt; - v = 0U; - } - } - - if (magnitudeIndex < mag.Length) - { - mag[magnitudeIndex] = v; - } + int first = ((nBytes - 1) % BytesPerInt) + 1; + magnitude[0] = Pack.BE_To_UInt32_Low(bytes, start, first); + Pack.BE_To_UInt32(bytes, start + first, magnitude, 1, nInts - 1); - return mag; + return magnitude; #endif } #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER - private static uint[] MakeMagnitude(ReadOnlySpan<byte> bytes) + private static uint[] MakeMagnitudeBE(ReadOnlySpan<byte> bytes) { int end = bytes.Length; // strip leading zeros - int firstSignificant; - for (firstSignificant = 0; firstSignificant < end && bytes[firstSignificant] == 0; firstSignificant++) + int start; + for (start = 0; start < end && bytes[start] == 0; start++) { } - if (firstSignificant >= end) + int nBytes = end - start; + if (nBytes <= 0) return ZeroMagnitude; - int nInts = (end - firstSignificant + 3) / BytesPerInt; - int bCount = (end - firstSignificant) % BytesPerInt; - if (bCount == 0) - { - bCount = BytesPerInt; - } - - if (nInts < 1) - return ZeroMagnitude; + int nInts = (nBytes + BytesPerInt - 1) / BytesPerInt; + Debug.Assert(nInts > 0); - uint[] mag = new uint[nInts]; + uint[] magnitude = new uint[nInts]; - uint v = 0; - int magnitudeIndex = 0; - for (int i = firstSignificant; i < end; ++i) - { - v <<= 8; - v |= bytes[i]; - bCount--; - if (bCount <= 0) - { - mag[magnitudeIndex] = v; - magnitudeIndex++; - bCount = BytesPerInt; - v = 0U; - } - } - - if (magnitudeIndex < mag.Length) - { - mag[magnitudeIndex] = v; - } + int first = ((nBytes - 1) % BytesPerInt) + 1; + magnitude[0] = Pack.BE_To_UInt32_Low(bytes.Slice(start, first)); + Pack.BE_To_UInt32(bytes.Slice(start + first), magnitude.AsSpan(1)); - return mag; + return magnitude; } #endif @@ -664,7 +618,7 @@ namespace Org.BouncyCastle.Math else { // copy bytes - this.magnitude = MakeMagnitude(bytes, offset, length); + this.magnitude = MakeMagnitudeBE(bytes, offset, length); this.sign = this.magnitude.Length < 1 ? 0 : sign; } } @@ -683,7 +637,7 @@ namespace Org.BouncyCastle.Math else { // copy bytes - this.magnitude = MakeMagnitude(bytes); + this.magnitude = MakeMagnitudeBE(bytes); this.sign = this.magnitude.Length < 1 ? 0 : sign; } } @@ -719,7 +673,7 @@ namespace Org.BouncyCastle.Math int xBits = BitsPerByte * nBytes - sizeInBits; b[0] &= (byte)(255U >> xBits); - this.magnitude = MakeMagnitude(b); + this.magnitude = MakeMagnitudeBE(b); this.sign = this.magnitude.Length < 1 ? 0 : 1; } @@ -766,7 +720,7 @@ namespace Org.BouncyCastle.Math // ensure the trailing bit is 1 (i.e. must be odd) b[nBytes - 1] |= 1; - this.magnitude = MakeMagnitude(b); + this.magnitude = MakeMagnitudeBE(b); this.nBits = -1; if (certainty < 1) |