Getter for securityToken
securityToken
Return a claim from the token given a key if it exist, else return null
value of the claim
Checks to see current token exists, and if so, check expiration time
true if valid
Helper method to verify token's secret matches publicKey string then parse token string into an complete object (header, payload, signature)
payload: object
Helper class to store security token and sessionKeySupplier contain methods to check if token is expired and needs to be refreshed