185 lines
3.9 KiB
C#
185 lines
3.9 KiB
C#
using System;
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using Org.BouncyCastle.Math;
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using Org.BouncyCastle.Utilities;
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namespace Org.BouncyCastle.Crypto.Parameters
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{
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public class DHParameters
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: ICipherParameters
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{
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private const int DefaultMinimumLength = 160;
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private readonly BigInteger p, g, q, j;
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private readonly int m, l;
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private readonly DHValidationParameters validation;
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private static int GetDefaultMParam(
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int lParam)
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{
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if (lParam == 0)
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return DefaultMinimumLength;
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return System.Math.Min(lParam, DefaultMinimumLength);
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}
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public DHParameters(
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BigInteger p,
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BigInteger g)
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: this(p, g, null, 0)
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{
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}
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public DHParameters(
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BigInteger p,
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BigInteger g,
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BigInteger q)
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: this(p, g, q, 0)
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{
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}
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public DHParameters(
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BigInteger p,
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BigInteger g,
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BigInteger q,
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int l)
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: this(p, g, q, GetDefaultMParam(l), l, null, null)
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{
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}
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public DHParameters(
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BigInteger p,
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BigInteger g,
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BigInteger q,
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int m,
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int l)
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: this(p, g, q, m, l, null, null)
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{
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}
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public DHParameters(
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BigInteger p,
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BigInteger g,
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BigInteger q,
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BigInteger j,
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DHValidationParameters validation)
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: this(p, g, q, DefaultMinimumLength, 0, j, validation)
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{
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}
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public DHParameters(
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BigInteger p,
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BigInteger g,
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BigInteger q,
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int m,
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int l,
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BigInteger j,
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DHValidationParameters validation)
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{
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if (p == null)
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throw new ArgumentNullException("p");
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if (g == null)
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throw new ArgumentNullException("g");
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if (!p.TestBit(0))
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throw new ArgumentException("field must be an odd prime", "p");
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if (g.CompareTo(BigInteger.Two) < 0
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|| g.CompareTo(p.Subtract(BigInteger.Two)) > 0)
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throw new ArgumentException("generator must in the range [2, p - 2]", "g");
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if (q != null && q.BitLength >= p.BitLength)
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throw new ArgumentException("q too big to be a factor of (p-1)", "q");
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if (m >= p.BitLength)
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throw new ArgumentException("m value must be < bitlength of p", "m");
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if (l != 0)
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{
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if (l >= p.BitLength)
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throw new ArgumentException("when l value specified, it must be less than bitlength(p)", "l");
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if (l < m)
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throw new ArgumentException("when l value specified, it may not be less than m value", "l");
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}
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if (j != null && j.CompareTo(BigInteger.Two) < 0)
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throw new ArgumentException("subgroup factor must be >= 2", "j");
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// TODO If q, j both provided, validate p = jq + 1 ?
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this.p = p;
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this.g = g;
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this.q = q;
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this.m = m;
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this.l = l;
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this.j = j;
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this.validation = validation;
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}
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public BigInteger P
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{
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get { return p; }
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}
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public BigInteger G
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{
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get { return g; }
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}
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public BigInteger Q
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{
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get { return q; }
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}
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public BigInteger J
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{
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get { return j; }
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}
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/// <summary>The minimum bitlength of the private value.</summary>
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public int M
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{
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get { return m; }
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}
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/// <summary>The bitlength of the private value.</summary>
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public int L
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{
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get { return l; }
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}
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public DHValidationParameters ValidationParameters
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{
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get { return validation; }
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}
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public override bool Equals(
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object obj)
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{
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if (obj == this)
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return true;
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DHParameters other = obj as DHParameters;
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if (other == null)
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return false;
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return Equals(other);
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}
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protected bool Equals(
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DHParameters other)
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{
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return p.Equals(other.p)
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&& g.Equals(other.g)
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&& Platform.Equals(q, other.q);
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}
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public override int GetHashCode()
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{
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int hc = p.GetHashCode() ^ g.GetHashCode();
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if (q != null)
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{
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hc ^= q.GetHashCode();
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}
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return hc;
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}
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}
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}
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