1 00:00:00,05 --> 00:00:03,00 - [Instructor] Metadata is data about data, 2 00:00:03,00 --> 00:00:04,00 or in other words, 3 00:00:04,00 --> 00:00:06,03 it's any information that can be derived from 4 00:00:06,03 --> 00:00:09,06 or attributed to a particular piece of data. 5 00:00:09,06 --> 00:00:12,02 Often this information provides additional detail 6 00:00:12,02 --> 00:00:14,09 that isn't included in an actual piece of data. 7 00:00:14,09 --> 00:00:17,06 It's information that describes the contents, 8 00:00:17,06 --> 00:00:20,08 provides context, or records associated information 9 00:00:20,08 --> 00:00:23,01 without altering the original data. 10 00:00:23,01 --> 00:00:24,04 While we'll focus on file 11 00:00:24,04 --> 00:00:26,07 and file system metadata in this course, 12 00:00:26,07 --> 00:00:30,00 metadata isn't strictly a computer related concept. 13 00:00:30,00 --> 00:00:32,05 For example, if we were to call a friend on the phone 14 00:00:32,05 --> 00:00:34,04 and have a conversation with them, 15 00:00:34,04 --> 00:00:36,04 the actual content of our conversation 16 00:00:36,04 --> 00:00:38,01 would be what we'd call the data. 17 00:00:38,01 --> 00:00:39,09 But anything else about that call such as 18 00:00:39,09 --> 00:00:41,09 the date and time it took place, 19 00:00:41,09 --> 00:00:43,05 a summary of the topics covered, 20 00:00:43,05 --> 00:00:45,00 or how long we spoke for, 21 00:00:45,00 --> 00:00:47,06 is metadata in relation to the conversation. 22 00:00:47,06 --> 00:00:49,09 These are things we could write down to describe 23 00:00:49,09 --> 00:00:53,01 our conversation should we need to recall it later. 24 00:00:53,01 --> 00:00:54,07 To move back to the realm of files, 25 00:00:54,07 --> 00:00:56,07 imagine that we had recorded our conversation 26 00:00:56,07 --> 00:00:58,03 to an audio file. 27 00:00:58,03 --> 00:01:01,06 This file would likely have metadata such as duration, 28 00:01:01,06 --> 00:01:04,02 possibly tags we add with a participant's names 29 00:01:04,02 --> 00:01:07,03 and other tags with conversation topics. 30 00:01:07,03 --> 00:01:09,05 As a file, it will have a creation date, 31 00:01:09,05 --> 00:01:11,04 though that might start out as the date when the file 32 00:01:11,04 --> 00:01:15,03 was created, not when the conversation actually took place. 33 00:01:15,03 --> 00:01:18,00 That file will have a size in bites representing 34 00:01:18,00 --> 00:01:20,01 how much disc space it takes up, 35 00:01:20,01 --> 00:01:22,09 and it will have to some degree access permissions, 36 00:01:22,09 --> 00:01:25,02 indications defining which users of a system 37 00:01:25,02 --> 00:01:26,08 can do what actions with it, 38 00:01:26,08 --> 00:01:28,09 depending on how it was created. 39 00:01:28,09 --> 00:01:30,06 Many other kinds of files have various 40 00:01:30,06 --> 00:01:32,09 metadata associated with them too. 41 00:01:32,09 --> 00:01:34,05 Images, for example, 42 00:01:34,05 --> 00:01:36,01 often contain information about 43 00:01:36,01 --> 00:01:38,01 the camera used to take a photo, 44 00:01:38,01 --> 00:01:40,00 the focal length and lens used, 45 00:01:40,00 --> 00:01:41,09 and sometimes geolocation information 46 00:01:41,09 --> 00:01:43,06 and the photographer's name. 47 00:01:43,06 --> 00:01:45,09 Video and audio files have a duration 48 00:01:45,09 --> 00:01:49,01 and sometimes will include a thumbnail or album cover. 49 00:01:49,01 --> 00:01:51,06 Documents will often have authorship information, 50 00:01:51,06 --> 00:01:54,09 revision history, a page count, sometimes a summary, 51 00:01:54,09 --> 00:01:57,02 and more stored in their metadata. 52 00:01:57,02 --> 00:01:59,05 And all of these files, no matter what kind they are, 53 00:01:59,05 --> 00:02:02,07 have a size and a name, various date information, 54 00:02:02,07 --> 00:02:04,08 and may have other kinds of attributes as well, 55 00:02:04,08 --> 00:02:07,07 like tags or color highlights or access permissions. 56 00:02:07,07 --> 00:02:10,06 While pretty much any data we can tag onto a file 57 00:02:10,06 --> 00:02:12,06 or associate with it is metadata, 58 00:02:12,06 --> 00:02:14,07 there are two primary ways of storing metadata 59 00:02:14,07 --> 00:02:16,04 that relate to files. 60 00:02:16,04 --> 00:02:19,06 One type of metadata is stored inside the file it describes. 61 00:02:19,06 --> 00:02:21,07 It's embedded within the file. 62 00:02:21,07 --> 00:02:25,03 Examples of embedded metadata are EXIF tags for photos, 63 00:02:25,03 --> 00:02:28,00 listing a camera model or lens focal distance, 64 00:02:28,00 --> 00:02:30,05 or an audio files ID3 tag listing 65 00:02:30,05 --> 00:02:33,01 a music artist, a track name, and so on. 66 00:02:33,01 --> 00:02:35,02 And some file metadata like the file's 67 00:02:35,02 --> 00:02:36,07 name and date information, 68 00:02:36,07 --> 00:02:39,01 it's access permissions and extended attributes 69 00:02:39,01 --> 00:02:40,09 are stored outside the file it describes, 70 00:02:40,09 --> 00:02:42,07 in the file system, not within 71 00:02:42,07 --> 00:02:44,08 the actual data of the file. 72 00:02:44,08 --> 00:02:46,07 We'll explore both of these types of metadata 73 00:02:46,07 --> 00:02:48,08 throughout the rest of the course. 74 00:02:48,08 --> 00:02:51,07 All this metadata can be gathered, stored, and indexed, 75 00:02:51,07 --> 00:02:54,01 making it easier to find files based on their name 76 00:02:54,01 --> 00:02:55,08 or some other aspect. 77 00:02:55,08 --> 00:02:57,00 With the basics behind us, 78 00:02:57,00 --> 00:02:58,08 let's move on to exploring metadata 79 00:02:58,08 --> 00:03:02,00 and its security implications in more depth.