Chaoji Li, an independent Chinese developer, has created an iOS app that allows users to save “digests” of important documents in the blockchain. This is not the first attempt to use the public ledger as a kind of cloud storage service – in 2014, BlockSign introduced a similar option.

Chaoji Li’s app, BtStamp, is now available on the iTunes App Store. It is a small download – just 0.3 MB of disk space – and has an English-language user interface. The app’s description says that it allows users to store “proof of the document” in the blockchain as a transaction.

Developer states

“Even if [the] BtStamp service is down or the app is unavailable, you can still search a registered document’s digest on well known bitcoin websites, locate the transaction and find out when it entered the blockchain”

This may sound good, but the procedure looks complicated for casual users. It is easy to upload a document (or its “digest”), but getting it back requires quite a bit more effort.

To use the blockchain entry as proof of the upload, users need to remember the transaction ID and decipher the encrypted message attached to it.

According to the creator, the app does not require users to provide their e-mail address and is totally anonymous.

Other developers have tried to provide similar functionality in the past. Last year, one of our editors used another program, Blocksign, to do something similar, namely to upload a document and verify it. BlockSign developers claim that they upload a full copy of the file to the blockchain. As of February 10th, the company’s website was online and could verify uploaded documents in seconds.

The “posting” of important documents to the public ledger has both supporters and detractors in the bitcoin community. Some people claim that this is one of the possible uses of the bitcoin technology, while others argue against such “spam” in the public ledger. In December 2014, several notable Bitcoin Core developers said that they may introduce several measures to prevent “spam” in the blockchain