Prove the existence of a web page in one click!

SingleFile extension generates bitcoin proofs

The SingleFile web extension, currently at the top of the recommendations for Firefox, has just been equipped with an even more innovative feature: the proof of a certain date of a web page thanks to Bitcoin. With tens of thousands of users worldwide, this extension allows you to archive any web page in one click. The success of this plugin is due to the lack of a proper export function in the most popular browsers on the market, such as Chrome and Firefox. SingleFile accomplishes the feat of generating a single file allowing a faithful export of a web page.

Breizh connection

SingleFile is edited by Gildas Lormeau, founder of the Rennes-based startup Capsule Code editor of the SEO4Ajax solution. Another startup from Rennes, Woleet is specialized in Bitcoin proof for all types of data. It is therefore quite natural that this collaboration was born, allowing all users of the extension to retrieve a neutral, irrefutable and usable evidence worldwide, including in court.

How does it work?

You will first have to install the plugin if it is not already done. Once installed, you will have to explicitly choose in the plugin’s options the creation of a proof of existence for each generated export.

You can download the plugin here :

Therefore each time a page is saved (by clicking only the extension icon) a proof will be generated and its download will be available within a day, once it is actually anchored in a Bitcoin block.

Step 1 : Choose Manage Extension menu
Step 2 : Open Extension preferences
Step 3 : Choose “add proof of existence” option and confirm conditions.

It is important to note that the operation is completely confidential. At no time is the locally saved content is shared with anyone. Only the digital fingerprint or hash of the document is needed to generate evidence in Bitcoin. There is no risk of anyone else but you knowing the content of the page you have “anchored”. In the same way, although the evidence is generated in the public blockchain (Bitcoin), it is impossible to “discover” it without having the proof receipt generated by Woleet, allowing you to find the mathematical link between the file’s fingerprint and the fingerprint embedded in a transaction that is visible to everyone.

How to retrieve the proof receipt?

A few hours after the export generation by the extension (between zero and 6 hours maximum) it will be possible to retrieve the corresponding proof through the dedicated verification site.

To do so, nothing could be easier: just drag and drop or choose the file on your computer, and the verification tool will offer you to download the proof if it is available. It is a small JSON format file, containing all the information you need to independently verify the evidence embedded in Bitcoin.


The adoption of data anchoring in Bitcoin is an innovative response to several needs for the company as well as the individual. From compliance, to integrity control, to intellectual property protection: having reliable and easily verifiable digital evidence at our disposal provides additional protection for our most sensitive data. The combination of this technology with a tool as convenient as SingleFile will democratize the use of Bitcoin as a global reference for digital truth.

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