The InterPlanetary File System identifies data with a content identifier derived from the content. If a file changes, its identifier changes, allowing an application to detect that it received different bytes.
A CID is not the same as a permanent host
A content identifier tells software what data to request, but the data must still be available from a peer or gateway. A valid CID does not guarantee that someone will continue storing the file.
Content addressing verifies retrieved bytes
If the downloaded content does not match the requested identifier, it is not the same object.
Gateways improve access but add dependence
HTTP gateways let ordinary browsers retrieve IPFS content. Relying on one gateway can reintroduce a single access point, so applications may use pinning services, multiple providers, or their own nodes.
Pinning is a storage commitment
Pinning services and node operators keep selected content available, but their retention and payment terms still matter.
Sources
Educational information, not investment advice.