We are happy to announce that the serious flaw in Dexter, which was discovered by the Nomadic Labs team in February, has been patched, and Dexter is back online. (For a full technical description of the flaw, see this blog post from Nomadic Labs). We welcome users back to the exchange.

A rewrite of the Dexter contract, produced by outside experts at Nomadic Labs and LIGO, is also in the works and should be released in a few weeks. This new version of Dexter will have improved functionality and consume less gas.

To avoid delays for the users of Dexter, we have decided to go live again with the patched contract for now, and will be announcing the new contract after it is audited by an independent third party.

We will have more news to share with you regarding the future of Dexter soon.

We write today to issue an apology to the community about the serious flaw that was found in Dexter.

We were recently notified by Nomadic Labs that in examining our contract in advance of the latest protocol upgrade proposal, they discovered a flaw in Dexter that would permit an attacker to remove funds that did not belong to them.

Very serious discussions ensued immediately to determine how to best preserve the safety of the funds in the Dexter contract. Ultimately, we decided that the only viable mechanism available appeared to be a so-called “White Knight” operation in which the funds…

We are building a mobile wallet for Tezos. We’ve been working on this project for several months, and since it’s open source, you can follow our progress here. It’s called Magma. We are thankful to the Tezos Foundation for providing us with the funding to make this possible.

Version 1.0

Magma will launch on both Android and iOS simultaneously. It will support the FA1.2 token standard, and FA2 when it is ready.

This is a non-custodial wallet. In case your phone is lost, stolen, or destroyed, your funds can be recovered from a seed phrase.

Dexter, our decentralized exchange, will be natively…


What a fine day for science.

– Dexter, Dexter’s Laboratory

As Nick Szabo first said, trusted third parties are security holes. Nowhere is this more apparent than in popular centralized digital asset exchanges. Even if you don’t get hacked or robbed, and your customer data doesn’t get leaked, many users are still probably getting fleeced by schemes ranging from front-running to wash trading to founders stealing their own customers’ funds.

The beauty of smart contracts on public blockchains is that this exact kind of behavior in many cases can be mitigated or avoided programmatically. Decentralized exchanges in their current…

Now that we know a little Michelson, let’s take a look at the Tezos blockchain, which is the “environment” in which our Michelson contracts are actually going to run.

This is not going to be an exhaustive overview of Tezos; we’re going to focus on those aspects that are most relevant from the perspective of a Michelson programmer. We’re going to look at a few useful tools, such as the tezos-client program that is in the alphanet docker container we installed last chapter and an online blockchain explorer.

These tools, like Tezos itself, are still immature and undergoing rapid development…

Michelson is the smart contract language of the Tezos blockchain. Roughly speaking, Michelson is to Tezos as the Ethereum Virtual Machine is to Ethereum. Both languages are stack-based, which means that computation is performed by mutating a sequence of data elements (the stack) according to some sequence of instructions (the program).

The most notable difference between Michelson and EVM is that Michelson is written in a human-legible text format, whereas EVM operations are represented as bytes. For example, if you look up the opcode table for the EVM you’ll see that the opcode 01 takes two numbers (off the top…



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