IdentityHelper.cs

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using System.IO;
using System.Reflection;
using System.Security.Cryptography;
using System.Text;
 
namespace System.Security;
 
internal static class IdentityHelper
{
    private static readonly char[] s_base32Char = new char[32]
    {
        'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
        'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
        'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3',
        '4', '5'
    };
 
    internal static string GetNormalizedUriHash(Uri uri)
    {
        return GetStrongHashSuitableForObjectName(uri.ToString());
    }
 
    internal static string GetNormalizedStrongNameHash(AssemblyName name)
    {
        byte[] publicKey = name.GetPublicKey();
        if (publicKey == null || publicKey.Length == 0)
        {
            return null;
        }
        using MemoryStream memoryStream = new MemoryStream();
        using BinaryWriter binaryWriter = new BinaryWriter(memoryStream);
        binaryWriter.Write(publicKey);
        binaryWriter.Write(name.Version.Major);
        binaryWriter.Write(name.Name);
        memoryStream.Position = 0L;
        return GetStrongHashSuitableForObjectName(memoryStream);
    }
 
    internal static string GetStrongHashSuitableForObjectName(string name)
    {
        using MemoryStream memoryStream = new MemoryStream();
        using BinaryWriter binaryWriter = new BinaryWriter(memoryStream);
        binaryWriter.Write(name.ToUpperInvariant());
        memoryStream.Position = 0L;
        return GetStrongHashSuitableForObjectName(memoryStream);
    }
 
    internal static string GetStrongHashSuitableForObjectName(Stream stream)
    {
        using SHA1 sHA = SHA1.Create();
        return ToBase32StringSuitableForDirName(sHA.ComputeHash(stream));
    }
 
    internal static string ToBase32StringSuitableForDirName(byte[] buff)
    {
        StringBuilder stringBuilder = new StringBuilder();
        int num = buff.Length;
        int num2 = 0;
        do
        {
            byte b = (byte)((num2 < num) ? buff[num2++] : 0);
            byte b2 = (byte)((num2 < num) ? buff[num2++] : 0);
            byte b3 = (byte)((num2 < num) ? buff[num2++] : 0);
            byte b4 = (byte)((num2 < num) ? buff[num2++] : 0);
            byte b5 = (byte)((num2 < num) ? buff[num2++] : 0);
            stringBuilder.Append(s_base32Char[b & 0x1F]);
            stringBuilder.Append(s_base32Char[b2 & 0x1F]);
            stringBuilder.Append(s_base32Char[b3 & 0x1F]);
            stringBuilder.Append(s_base32Char[b4 & 0x1F]);
            stringBuilder.Append(s_base32Char[b5 & 0x1F]);
            stringBuilder.Append(s_base32Char[((b & 0xE0) >> 5) | ((b4 & 0x60) >> 2)]);
            stringBuilder.Append(s_base32Char[((b2 & 0xE0) >> 5) | ((b5 & 0x60) >> 2)]);
            b3 >>= 5;
            if ((b4 & 0x80u) != 0)
            {
                b3 = (byte)(b3 | 8u);
            }
            if ((b5 & 0x80u) != 0)
            {
                b3 = (byte)(b3 | 0x10u);
            }
            stringBuilder.Append(s_base32Char[b3]);
        }
        while (num2 < num);
        return stringBuilder.ToString();
    }
}