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What S3 Is: Buckets, Objects and Keys
What S3 Is: Buckets, Objects and Keys Amazon S3 stores files in the cloud. A bucket is a container. Each file is an object . Its name/path is the key , like photos/a1.jpg . Every object has a URL. One wrong permission makes files downloadable by anyone . Many real data leaks were just S3 buckets lef
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What this card says
What it is
Amazon S3 stores files in the cloud.
A bucket is a container. Each file is an object. Its name/path is the key, like photos/a1.jpg.
Why it matters for security
Every object has a URL. One wrong permission makes files downloadable by anyone.
Many real data leaks were just S3 buckets left open to “Everyone”.
Watch out
Attackers guess bucket names like companyname-backup and try them automatically.
| Term | Meaning | Example |
|---|---|---|
| Bucket | Top-level container, name is globally unique across all AWS… | ravindra-reels-media-pune |
| Object | One file plus its metadata (content type, size, tags) | a video, an image, a PDF |
| Key | The full "path" name of the object inside the bucket | videos/2026/09/a1b2c3.mp4 |
| Prefix | The part of the key before the last / – the console shows… | videos/2026/09/ |
| Region | Where the bucket physically lives; choose one close to your… | ap-south-1 (Mumbai) |
Learn more in the lesson: 14.1 What S3 Is: Buckets, Objects and Keys