The OpenTimestamps standard is a recent development for blockchain timestamp proofs. It allows to demonstrate that certain information, as documents or digital signatures, exists before a certain date.

Unlike traditional solutions (RFC 3161/ANSI X9.95, RFC 4998), it achieves this without trusted third parties or long-term maintenance needs. And unlike first-generation blockchain approaches, without their costs.

By employing an open industry standard instead of proprietary formats, different organizations can collaborate, while users can share tools and knowledge between various solutions.

At Signatura we have been working on OpenTimestamps support to make a more efficient use of the Bitcoin blockchain, and today’s…

La idea de esta nota introductoria es ser un punto de partida; no apunta a explicar teoría monetaria o criptografía, tampoco pretende convencer a nadie, sino contar de qué se trata y cómo nos resulta útil a muchos de nosotros.

Para ello se intenta dar una explicación básica de cada tema, pero haciendo uso de links al mencionar ciertos conceptos que pueden profundizarse en otras fuentes (generalmente en español, pero no siempre posible).


Bitcoin es una construcción social a partir de una tecnología de dinero digital, con un protocolo, unidad monetaria y red P2P del mismo nombre.

Para empezar, debemos…

Citi organized a global challenge to source solutions that promote integrity, accountability and transparency in the public sector. It was arranged in 6 countries, with one of the chapters being celebrated in Buenos Aires with the support of Argentina’s national government.

We decided to be part of it exploring the procurement processes ideas we talked about time ago in this blog (more on that here, and here). Federico did a great work explaining what they achieve, and we were pleased to win both, the main and audience choice awards.

More information about our participation at Citi T4I Challenge can be…

We’ve been silently adding features to Signatura, with a new batch of them becoming available in today’s release. Here’s what we’ve been working on:


If you regularly need the same group of people to access your documents, this will be of help. Instead of manually selecting everyone on each document, you can now define a team, set it as an observer in all the documents you want, and everyone in it will get access.

It is irrelevant if they are signers or not, and documents will be encrypted as usual (with team’s key rather than individual ones).


Last year we did a blog post on procurement processes such as requests for proposals or calls for tenders, and how to prevent common fraud schemes found on them. Recently, we had to further explore on that blockchain-based solution. As an addition to that post, we found these benefits:

Proposal/bid secrecy

The result of a cryptographic hash function is applied to the proposal and its result is blockchain-recorded. Proposal content is never exposed, in fact, it may not even be sent until the deadline has passed.

Photo from Pixabay (CC0).

Since there is no possible way for whoever manages the process to leak or to know…

In the last month we were lucky to be part of a few events and competitions, here a brief summary of our participation on them.

Argentina’s Central Bank hackathon award

The president (center) and vice president (left) of Argentina’s Central Bank talking with Signatura during financial innovation hackathon.

Weeks ago we took part on the financial innovation hackathon organized by Argentina’s Central Bank.

There we used Signatura to build a proof of concept called Financial Passport. It’s a platform that allows its users to validate their personal details, and upload their financial documentation, so it can be shared with the financial institutions of their choice.

In it, information is encrypted client-side to avoid privacy issues, and the whole flow is digitally signed with…

Today we are excited to launch the public beta of Signatura, our digital signature and notarization platform.

Time ago we released its private beta and signed its first document. Since then, we have been squashing bugs, testing and even undergoing some radical UX changes, to finally reach the moment when we are comfortable to open the beta up to the general public.

So from now on there are no more invite codes, feel free to give it a try and send us any feedback you have, we really appreciate it. :)

Introducing Signatura

Signatura allows multiple parties to jointly sign documents, legally…

We started developing BitCourt as an arbitration platform, so commercial disputes could be resolved quickly and professionally. This goal requires non-repudiation of contracts, evidence and verdicts, so we put special emphasis in digital signature and notarization processes, creating an API to use blockchain and smart contract technology to make them secure and reliable.

In the meantime, being one of the very few companies in Latin America working with non-monetary blockchain applications gave us the opportunity to know and get in the conversation with many businesses, public offices and financial institutions. …

Calls for tenders, requests for proposals and sealed-bid auctions, while less frequent in the private sector, are common and necessary processes on government agencies. However, no matter the good intentions for implementing them, they are still a constant source of fraud and corruption.

Their procedures usually involve one of these alternatives:

  • Safeguarded sealed envelopes: printed bids are delivered in sealed envelopes and kept in custody until deadline, when they are opened for evaluation. Old fashioned, but still used in many places.
  • Software solutions: bids are submitted in digital form and managed using an eTendering/eProcurement/eGovernment platform.

Both methods require trusting that…

Since late ’70s digital signatures have been successfully used to provide authentication, integrity and non-repudiation of a message and its source.

Lotus Notes 1.0 (1989), first widely marketed software package to offer digital signature.

Algorithms such as DSA, PKCS #1 (RSA), ECDSA and others were or are used in digital signature solutions like Pretty Good Privacy (PGP) and Adobe Sign, among others.

Bitcoin’s blockchain background

Bitcoin uses digital signatures (ECDSA) to prove ownership of funds, so sending bitcoins requires the owner of them to digitally sign authorizing the transfer. This transaction is sent to Bitcoin’s public network and later recorded in Bitcoin’s public database (blockchain), so anyone can verify it by checking its digital signature.


Franco Amati

/me: alpaca-sock-wearing crypto-terrorist (bitcoiner), drapetómano (eleuteromaníaco), nómada wannabe, agorista (libertario), pro-chumbo, ateo propagandista.

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