Drop here a file to stamp
an .ots proof file to verify
The hash is calculated on your browser preserving your privacy. More...
Timestamping proof download will start automatically after uploading document.
A timestamp proves that some data existed prior to some point in time. OpenTimestamps defines a set of operations for creating provable timestamps and later independently verifying them. At the time of writing timestamping on the Bitcoin blockchain is supported, the format is flexible enough to support a variety of methods. More.
Anyone could realize a timestamp with the permissionless blockchain by paying the transaction fees, for your convenience we offer calendar servers that perform this operation for you. These servers are free to use and they don't require any registration or api key.
$ pip3 install opentimestamps-client $ ots stamp my-fileMore
$ git clone https://github.com/opentimestamps/java-opentimestamps $ cd java-opentimestamps $ mvn install $ java -jar target/OtsCli.jar stamp my-fileMore
Client tool to perform stamping of files through a calendar server and to verify OpenTimestamps proofopentimestamps-client
Calendar Server receiving timestamp request from clientsopentimestamps-server
Common library & Client tooljava-opentimestamps