The "keys" are explained in the Bible. Read it.
Clearly the RCC and EOC believe that a special power was given to Peter and then the rest of the disciples. I think a much more straightforward interpretation is consistent with Jesus' earthly ministry. The keys of heaven are FAITH in JESUS, without this you will not be saved. The binding and loosening is the preaching of the gospel. The listeners that hear and believe are bound by the Holy Spirit. The listeners who hear but don't believe are free of the Holy Spirit, loosed.