public SharePointContextToken(string issuer, string audience, DateTime validFrom, DateTime validTo, IEnumerable<JsonWebTokenClaim> claims, SecurityToken issuerToken, JsonWebSecurityToken actorToken)
     : base(issuer, audience, validFrom, validTo, claims, issuerToken, actorToken)
 {
 }

        private static string IssueToken(
            string sourceApplication,
            string issuerApplication,
            string sourceRealm,
            string targetApplication,
            string targetRealm,
            string targetApplicationHostName,
            bool trustedForDelegation,
            IEnumerable<JsonWebTokenClaim> claims,
            bool appOnly = false)
        {
            if (null == SigningCredentials)
            {
                throw new InvalidOperationException("SigningCredentials was not initialized");
            }

            #region Actor token

            string issuer = string.IsNullOrEmpty(sourceRealm) ? issuerApplication : string.Format("{0}@{1}", issuerApplication, sourceRealm);
            string nameid = string.IsNullOrEmpty(sourceRealm) ? sourceApplication : string.Format("{0}@{1}", sourceApplication, sourceRealm);
            string audience = string.Format("{0}/{1}@{2}", targetApplication, targetApplicationHostName, targetRealm);

            List<JsonWebTokenClaim> actorClaims = new List<JsonWebTokenClaim>();
            actorClaims.Add(new JsonWebTokenClaim(JsonWebTokenConstants.ReservedClaims.NameIdentifier, nameid));
            if (trustedForDelegation && !appOnly)
            {
                actorClaims.Add(new JsonWebTokenClaim(TrustedForImpersonationClaimType, "true"));
            }

            // Create token
            JsonWebSecurityToken actorToken = new JsonWebSecurityToken(
                issuer: issuer,
                audience: audience,
                validFrom: DateTime.UtcNow,
                validTo: DateTime.UtcNow.Add(HighTrustAccessTokenLifetime),
                signingCredentials: SigningCredentials,
                claims: actorClaims);

            string actorTokenString = new JsonWebSecurityTokenHandler().WriteTokenAsString(actorToken);

            if (appOnly)
            {
                // App-only token is the same as actor token for delegated case
                return actorTokenString;
            }

            #endregion Actor token

            #region Outer token

            List<JsonWebTokenClaim> outerClaims = null == claims ? new List<JsonWebTokenClaim>() : new List<JsonWebTokenClaim>(claims);
            outerClaims.Add(new JsonWebTokenClaim(ActorTokenClaimType, actorTokenString));

            JsonWebSecurityToken jsonToken = new JsonWebSecurityToken(
                nameid, // outer token issuer should match actor token nameid
                audience,
                DateTime.UtcNow,
                DateTime.UtcNow.Add(HighTrustAccessTokenLifetime),
                outerClaims);

            string accessToken = new JsonWebSecurityTokenHandler().WriteTokenAsString(jsonToken);

            #endregion Outer token

            return accessToken;
        }

 public static SharePointContextToken Create(JsonWebSecurityToken contextToken)
 {
     return new SharePointContextToken(contextToken.Issuer, contextToken.Audience, contextToken.ValidFrom, contextToken.ValidTo, contextToken.Claims);
 }

        private static string GetClaimValue(JsonWebSecurityToken token, string claimType)
        {
            if (token == null)
            {
                throw new ArgumentNullException("token");
            }

            foreach (JsonWebTokenClaim claim in token.Claims)
            {
                if (StringComparer.Ordinal.Equals(claim.ClaimType, claimType))
                {
                    return claim.Value;
                }
            }

            return null;
        }