qubit on Nostr: What are HEX keys?

{ "id": "96c2383f6288ad9e4bde24ad89ec8b7964895fa87df1997bd757e469d2b0ee1f", "pubkey": "ddd847839b002118ab020762ad9a9104c9c2390ebc65bc693f7b2fdc5edaac27", "created_at": 1677968769, "kind": 1, "tags": [ [ "e", "57e1606f2a2c165a26cdc6fd7b686d06a22bc300c1f55e661e9bd7eba45cb36c" ], [ "e", "113231c91604ea6abf04379e72ce6135406d42dca43417a15eb4c301d9afef4e" ], [ "p", "1bc70a0148b3f316da33fe3c89f23e3e71ac4ff998027ec712b905cd24f6a411" ], [ "p", "9f376635bfcc2021daa2ddf5b93420e0a8a468ba35ccf613587948697bc42976" ], [ "p", "1577e4599dd10c863498fe3c20bd82aafaf829a595ce83c5cf8ac3463531b09b" ] ], "content": "What are HEX keys?", "sig": "cd091c5407f09a9d54e494a67c6f6a0b025901e05023b74d9bbc29069af4010ac3318c8353a88405f6d17c073205a50cd2bc7b2d93f235067e8ab90d887185b7" }