Permissions a Secondary Key has over the Identity. A null value means the key has all permissions of that type (i.e. if tokens is null, the key has permissions over all of the Identity's Security Tokens)
list of Transaction Groups this key can execute. Having permissions over a TxGroup means having permissions over every TxTag in said group. Transaction permissions are the result of combining these with the transactions array. If transactions is null, then this value is redundant