An alternative to FreeTSA
By BlockchainSignLast updated
FreeTSA is a free, public RFC 3161 timestamping authority. You hash your file, send a timestamp request, and get back a signed token. It is a piece of infrastructure rather than a product, and for the people it is aimed at that is a feature. This page is about the case where you are not that person.
What FreeTSA is
A timestamping authority implementing RFC 3161, offered free. The workflow is openssl:
openssl ts -query -data file.pdf -sha256 -cert -out file.tsq
curl -H "Content-Type: application/timestamp-query" \
--data-binary @file.tsq https://freetsa.org/tsr > file.tsr
openssl ts -verify -in file.tsr -queryfile file.tsq -CAfile cacert.pem
Your file never leaves the machine — the request contains only its hash. The output is a .tsr token you keep alongside the file.
This is genuinely useful and genuinely free, and for scripting timestamps into a build or an archive it is hard to beat. Several other services in this category, including ProofStamper, use FreeTSA underneath.
The friction, which is entirely about audience
Nothing here is a criticism of the software. It is a question of who has to use the result.
- The command line is the interface. There is no dashboard, no account, no support.
- You must keep the token. The
.tsrfile is the proof. Lose it and there is nothing to fall back on; the authority does not keep a record for you. - Verification requires the certificate chain. You need the CA certificate to verify, and you need it to still be available and trusted years later.
- The output is not presentable. A
.tsris a binary blob. Handing one to a client, an insurer or opposing counsel means also teaching them RFC 3161. - No guarantees. It is a free service run as a public good, with the availability and support that implies.
Where we sit
| FreeTSA | BlockchainSign | |
|---|---|---|
| Cost | Free | $3.00–$9.99 per certificate |
| Interface | openssl on the command line | A browser page |
| What you keep | A .tsr token file |
A certificate with a public transaction link |
| If you lose it | Proof gone | The hash is in the transaction itself |
| Trust rests on | The TSA's certificate chain | A public Ethereum ledger |
| Explaining it | You are the documentation | A certificate plus an Etherscan link |
| Availability | Best effort, free service | Paid service, direct support |
| Your file | Never sent | Never sent |
The privacy model is the same on both sides: only the hash goes anywhere. We do not claim an advantage there, because there isn't one.
What we sell is the difference between a token and a document. Our certificate names the file's hash, the transaction, and a link anyone can open. Someone with no cryptography background can follow it. A .tsr cannot be followed by anyone who does not already know what it is.
Choose FreeTSA if
- You are comfortable with openssl and will reliably keep token files.
- You are automating timestamps in a build, a pipeline or an archive.
- You want RFC 3161 specifically.
- Cost is the deciding factor.
Choose us if
- Someone non-technical will eventually have to look at this.
- You want a certificate document rather than a binary token.
- You would rather not depend on a certificate chain staying available.
- You want the record on a public ledger you can read directly.
If you are technical and the proof is for you, use FreeTSA. It costs nothing and it works. The free SHA-256 hash generator on this site will give you the hash to feed it, with nothing sent anywhere.