jeremylandon / apple-auth Goto Github PK

    using var algorithm = ECDsa.Create();
    algorithm.ImportPkcs8PrivateKey(privateKey, out int _);

    var key = new ECDsaSecurityKey(algorithm) { KeyId = "KEY_ID" };

    tokenDescriptor.SigningCredentials = new SigningCredentials(key, SecurityAlgorithms.EcdsaSha256);
    var tokenHandler = new JwtSecurityTokenHandler();

    var jwt = tokenHandler.CreateEncodedJwt(tokenDescriptor);

 private async Task<byte[]> getPrivateKey()
  {
    var path = Directory.GetCurrentDirectory()+"/Resources/AuthKey_G3F7S685MC.p8";    
    string content = await System.IO.File.ReadAllTextAsync(path);
    string[] keyLines = content.Split('\n');
    content = string.Join(string.Empty, keyLines.Skip(1).Take(keyLines.Length - 2));

    return Convert.FromBase64String(content);
  }

  public async Task<string> GetSecret()
  {         
    var _privateKey = await getPrivateKey();
    

    using (var algorithm = GetEllipticCurvealgoritm(_privateKey))
    {
      var credentials = new SigningCredentials(new ECDsaSecurityKey(algorithm), SecurityAlgorithms.EcdsaSha256);   
      var tokenHandler = new JwtSecurityTokenHandler();   
      return tokenHandler.CreateEncodedJwt(new SecurityTokenDescriptor{
        Issuer = _apple_teamID,
        Audience = _apple_audience,
        Subject = new ClaimsIdentity(new[] { new Claim("sub", _apple_subject) }),
        Expires = DateTime.UtcNow.AddDays(10),
        IssuedAt = DateTime.UtcNow,
        NotBefore = DateTime.UtcNow,
        SigningCredentials = credentials
      });  
    }        
  }

  private ECDsa GetEllipticCurvealgoritm(byte[] privateKey)
  {
    var keyParams = (ECPrivateKeyParameters) PrivateKeyFactory.CreateKey(privateKey);

    var q = keyParams.Parameters.G.Multiply(keyParams.D).Normalize();

    return ECDsa.Create(new ECParameters{
      Curve = ECCurve.CreateFromValue(keyParams.PublicKeyParamSet.Id),
      D = keyParams.D.ToByteArrayUnsigned(),
      Q = {
        X = q.XCoord.GetEncoded(),
        Y = q.YCoord.GetEncoded()
      }
    });
  }