Unity_Web/Assets/Best HTTP/Source/SecureProtocol/crypto/prng/drbg/DrbgUtilities.cs

116 lines
3.8 KiB
C#

#if !BESTHTTP_DISABLE_ALTERNATE_SSL && (!UNITY_WEBGL || UNITY_EDITOR)
#pragma warning disable
using System;
using System.Collections.Generic;
using BestHTTP.SecureProtocol.Org.BouncyCastle.Crypto.Utilities;
namespace BestHTTP.SecureProtocol.Org.BouncyCastle.Crypto.Prng.Drbg
{
internal class DrbgUtilities
{
private static readonly IDictionary<string, int> MaxSecurityStrengths =
new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
static DrbgUtilities()
{
MaxSecurityStrengths.Add("SHA-1", 128);
MaxSecurityStrengths.Add("SHA-224", 192);
MaxSecurityStrengths.Add("SHA-256", 256);
MaxSecurityStrengths.Add("SHA-384", 256);
MaxSecurityStrengths.Add("SHA-512", 256);
MaxSecurityStrengths.Add("SHA-512/224", 192);
MaxSecurityStrengths.Add("SHA-512/256", 256);
}
internal static int GetMaxSecurityStrength(IDigest d)
{
return MaxSecurityStrengths[d.AlgorithmName];
}
internal static int GetMaxSecurityStrength(IMac m)
{
string name = m.AlgorithmName;
return MaxSecurityStrengths[name.Substring(0, name.IndexOf("/"))];
}
/**
* Used by both Dual EC and Hash.
*/
#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER || _UNITY_2021_2_OR_NEWER_
internal static void HashDF(IDigest digest, ReadOnlySpan<byte> seedMaterial, int seedLength, Span<byte> output)
#else
internal static void HashDF(IDigest digest, byte[] seedMaterial, int seedLength, byte[] output)
#endif
{
// 1. temp = the Null string.
// 2. .
// 3. counter = an 8-bit binary value representing the integer "1".
// 4. For i = 1 to len do
// Comment : In step 4.1, no_of_bits_to_return
// is used as a 32-bit string.
// 4.1 temp = temp || Hash (counter || no_of_bits_to_return ||
// input_string).
// 4.2 counter = counter + 1.
// 5. requested_bits = Leftmost (no_of_bits_to_return) of temp.
// 6. Return SUCCESS and requested_bits.
int outputLength = (seedLength + 7) / 8;
int digestSize = digest.GetDigestSize();
int len = outputLength / digestSize;
int counter = 1;
#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER || _UNITY_2021_2_OR_NEWER_
Span<byte> dig = digestSize <= 128
? stackalloc byte[digestSize]
: new byte[digestSize];
Span<byte> header = stackalloc byte[5];
Pack.UInt32_To_BE((uint)seedLength, header[1..]);
#else
byte[] dig = new byte[digestSize];
byte[] header = new byte[5];
Pack.UInt32_To_BE((uint)seedLength, header, 1);
#endif
for (int i = 0; i <= len; i++, counter++)
{
header[0] = (byte)counter;
#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER || _UNITY_2021_2_OR_NEWER_
digest.BlockUpdate(header);
digest.BlockUpdate(seedMaterial);
digest.DoFinal(dig);
int bytesToCopy = System.Math.Min(digestSize, outputLength - i * digestSize);
dig[..bytesToCopy].CopyTo(output[(i * digestSize)..]);
#else
digest.BlockUpdate(header, 0, header.Length);
digest.BlockUpdate(seedMaterial, 0, seedMaterial.Length);
digest.DoFinal(dig, 0);
int bytesToCopy = System.Math.Min(digestSize, outputLength - i * digestSize);
Array.Copy(dig, 0, output, i * digestSize, bytesToCopy);
#endif
}
// do a left shift to get rid of excess bits.
if (seedLength % 8 != 0)
{
int shift = 8 - (seedLength % 8);
uint carry = 0;
for (int i = 0; i != outputLength; i++)
{
uint b = output[i];
output[i] = (byte)((b >> shift) | (carry << (8 - shift)));
carry = b;
}
}
}
}
}
#pragma warning restore
#endif