Example of how to use Microsoft's System.IdentityModel.Tokens.Jwt to create a JWT Token

JwtTokenCreator.cs

using System.Collections.Generic;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Linq
using System.Text;
using Microsoft.IdentityModel.Tokens;

public class JwtTokenCreator
	{
		private readonly JwtSecurityTokenHandler _jwtSecurityTokenHandler;

		public JwtTokenCreator()
		{
			this._jwtSecurityTokenHandler = new JwtSecurityTokenHandler();
		}

		public string GenerateJwtToken(string secretKey, IReadOnlyDictionary<string, string> payloadContents, string encryptionAlgorithm)
		{
			var securityKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(secretKey));
			var signingCredentials = new SigningCredentials(securityKey, encryptionAlgorithm);

			var payloadClaims = payloadContents.Select(c => new Claim(c.Key, c.Value));

			var payload = new JwtPayload(payloadClaims);
			var header = new JwtHeader(signingCredentials);
			var securityToken = new JwtSecurityToken(header, payload);

			return this._jwtSecurityTokenHandler.WriteToken(securityToken);
		}
	}