How Rabbithole verifies your files
Why this matters
When a file is stored outside your browser, two different questions appear:
- Can someone read it?
- Can someone replace it without you noticing?
Encryption answers the first question. File verification answers the second.
If a file is silently replaced on the way to you, Rabbithole refuses to open it. You get a failed download or integrity error instead of a tampered file.
Blob Storage verification
With Blob Storage, the browser does not trust the gateway blindly.
Ask the canister for the expected file info
The browser gets the expected file hash and related metadata from your canister.
Verify that this metadata is authentic
The metadata is delivered through an Internet Computer certification flow, so the browser can verify that it really came from your canister.
Compare the downloaded file against that hash
If the downloaded file does not match, the browser rejects it before opening.
On-chain Storage verification
With On-chain Storage there is no external storage gateway in the file path, so the verification path is simpler.
The browser still verifies what it receives before decryption, but it does not need a separate external delivery path.
What is certified by the Internet Computer
For Blob Storage, Rabbithole certifies the metadata that tells the browser which file to expect.
That includes values such as:
- the file hash
- file size
- content type
This lets the browser detect tampering before decryption.
What is checked locally in the browser
The browser recomputes the hash of the downloaded file and compares it with the certified value from the canister.
Only if they match does decryption continue.
Certification proves that the expected metadata really came from your canister.
Local verification proves that the downloaded encrypted file matches that metadata.
Technical details
Certified metadata and local hashing
Blob Storage path
For Blob Storage, the browser performs two linked checks:
- It verifies certified metadata returned by your canister.
- It hashes the downloaded blob locally and compares it with the certified hash.
The certified metadata currently includes:
- the expected file hash
- file size
- content type
The browser verifies that this metadata was certified by the Internet Computer, then verifies that the downloaded blob matches it byte-for-byte.
What hash is used
Rabbithole uses SHA-256 for the certified file hash and for local comparison in the browser.
Why certification and hashing are separate
- Certification proves the expected metadata really came from your canister.
- Local hashing proves the downloaded blob matches that metadata.
Both checks are needed. Certification alone does not prove the gateway delivered the right file. Local hashing alone does not prove the expected hash was trustworthy.
On-chain Storage path
With On-chain Storage there is no separate external delivery layer, so the verification path is shorter:
- the browser downloads file data from your canister
- the browser still verifies integrity before opening
- decryption only happens after integrity passes