AES-GCM file encryption
Encrypt a local file with a password and download an authenticated StillKit envelope. Your inputs stay in this browser tab.
Your result
A little input. A useful result.
Your result will appear here.How to use aes-gcm file encryption
Encrypt a local file with a password and download an authenticated StillKit envelope. This free tool runs locally after you choose to start.
- Choose supported files from your device.
- Adjust password (never stored) as needed.
- Choose the action button. Review the result, then copy text or download a file when available.
- Choose Clear all when finished to remove inputs and results from the interface.
Limits, without the small print.
All cryptography runs locally in Web Crypto. Never paste live secrets into a device you do not trust. Inputs are not stored or sent. A compromised browser or served application can read inputs. Maximum 10 MB plaintext. AES-256-GCM with random salt, IV and PBKDF2-SHA-256. Original filename is not included.
One job runs at a time. You can cancel it; jobs stop after 30 seconds. Browser and device capabilities affect performance.
Understand the safeguards →What this tool does
Encrypt a local file with a password and download an authenticated StillKit envelope.
Example input
Select a supported local file; the visible settings are a starting example.
What to expect
Review the generated local preview or downloadable copy before using it.
A couple of useful answers.
Does aes-gcm file encryption upload my data?
No. This tool processes your input in a browser worker. Your text and files are not sent to an application server. The static host receives page and asset requests; see our privacy explanation.
Is this tool free for work and study?
Yes. No account, paid API, usage subscription or watermark fee is required. You remain responsible for your content rights and checking results. Hosting providers and their free tiers are separate from this open-source software.
What should I check before relying on the result?
All cryptography runs locally in Web Crypto. Never paste live secrets into a device you do not trust. Inputs are not stored or sent. A compromised browser or served application can read inputs. Maximum 10 MB plaintext. AES-256-GCM with random salt, IV and PBKDF2-SHA-256. Original filename is not included. Review important outputs against the source, especially financial, legal, identity, medical and research calculations.