Don’t Fuck Anybody Who Wants to Get Your Consent Uploaded to the Blockchain

Consent needs to be fluid, and the blockchain is anything but.
Image: Shutterstock / Composition: Samantha Cole

Contrary to the endless stream of pitches in my inbox, the solution to all human afflictions is not “put it on the blockchain.” That’s not stopping one company from trying to teach people respect for sexual boundaries by offering digital consent contracts and uploading the so-called "proof" of consent to a blockchain.

Dutch company LegalThings announced last week that it plans to launch a mobile app called LegalFling, which will “verify explicit consent before having sex,” according to its website. “With the click of a button […] LegalFling allows you to request consent from any of your contacts. Sit back and relax while your fling confirms.”


Using the LegalFling app, when two or more people want to have consensual sex, they both digitally “sign” a contract in the app. LegalFling then attaches a cryptographic hash of the interaction (a string of characters that represent the text) to a small amount of cryptocurrency that’s sent through the Waves network, a blockchain platform in the same family as Bitcoin and Ethereum. The hash is then permanently placed on the Waves blockchain for anyone to see.

A blockchain, whether it’s Bitcoin’s, or Ethereum’s, or Waves’, is basically a public ledger—it's a list of transactions that anyone can see, and it's secured with cryptography and expensive computing power. The ledger is shared between everybody running the blockchain's software, making it nigh-impossible to edit without anybody noticing.

The app was thoroughly panned last week for being a clumsy gimmick started by men, and for fundamentally misunderstanding the concept of sexual consent—which cannot be managed by a document. It needs to be a fluid process, open to revocation at any time, and legal contracts give off the exact opposite vibe. The app promises that consent can be revoked with a tap, but records on the blockchain are permanent.

LegalFling claims its contracts are “live documents” inside the app that can be appended with more information if consent is later withdrawn, the initial blockchain entry confirming consent will still be there, even if it’s just a hash value. It’s enough to make you wonder why LegalThings felt blockchain technology was necessary at all.


Read more: The Problem With Sexual Consent Apps

“There is such a long list of things that don’t belong on the blockchain, and this is high on the list” Eva Galperin, director of cybersecurity at the EFF, told me in a phone conversation. “It also reflects a profound lack of understanding of how the blockchain works, so whoever proposed this failed to understand the blockchain, and consent, and sex."

Let’s play along with LegalFling’s pitch for a moment. Say I’m getting ready for a date and am unsure of what will happen next. Instead of communicating with the other person (something LegalThings CEO Rick Schmitz said in a press release can be “a little uncomfortable”), I send them a request to agree to what boils down to a Terms of Service for the use of my body. Along with actual sex acts, those terms can include whatever rules about nudes and sexts I agree to send and receive. If my date agrees and “signs” the contract, then the interaction data is hashed and uploaded to the blockchain, where it lives forever.

Consent isn’t a one-time transaction.

But what if I change my mind about the agreement mid-date? What about mid-sex? Revoking consent or altering the terms “with a tap” is a feature of the app, so apparently I need to stop what we’re doing, find my phone and swipe “no” on this app before they are legally obligated to not assault me. Something tells me that this extremely unrealistic, and even potentially dangerous, in practice.


“Revoking consent is as simple as saying ‘No,’” Arnold Daniels, a spokesperson for the company told me in an email. “The app will remind both parties the rules of the game in advance. This is a general concern, so we're making sure that the app reminds you that ‘no’ really means ‘no.’ The benefit of LegalFling is that this can be done at the moment it counts most, right before engaging in sex.”

This kind of thinking either misunderstands or ignores the concept of enthusiastic, affirmative consent, which is based on each party communicating “yes” throughout the encounter, and not just stopping if and only if someone explicitly says no. “The moment it counts most” is not right before sex. Consent isn’t a one-time transaction. It’s a constant, fluid communication between two (or more) people, that involves checking in on each other throughout the interaction, making sure everyone is comfortable and having fun.

"The fact of there being an explicit consent on record… may prevent victims from coming forward, or from obtaining justice.”

Even if you use the app later to revoke consent—essentially saying that assault happened on the date—and a new hash is put on the blockchain, the original hash confirming consent is still there in an earlier block.

Even though the contracts inside LegalFling’s app can be appended with new information, the blockchain’s main value proposition is permanence: Once something is uploaded, it’s unalterable. A piece of data on the blockchain pins it to a particular time, in an uneditable format. This could be useful for things like supply chain management or property deed registry, but not consent.


This is where a static record of consent crosses over from being wrong-headed into being potentially dangerous. The Twitter account for Live Contracts, the LegalThings technology behind the LegalFling app, tweeted to anonymity and privacy researcher Sarah Jamie Lewis that the LegalFling app is “intended to be a tech implementation of” a proposed Swedish law that would reportedly require explicit consent before sex.

“There are clearly many issues around such an implementation, the main one being that while a victim might consent in one particular moment, they have every right to revoke that consent in the next,” Lewis told me in a direct message over Twitter. “In cases of someone ignoring that revocation, and committing sexual assault, the fact of there being an explicit consent on record (even if it was later, verbally revoked [ but not in the app]) may prevent victims from coming forward, or from obtaining justice.”

However, since this is new technology, there’s no telling how LegalFling contracts will stand up in court despite the app’s legal-ish branding. Neil Brown, a UK lawyer specializing in technology and internet law, wasn’t convinced of LegalFling’s ability to serve as evidence in court when I asked him for his impressions. “The real test is whether this stands up in court,” he said in a Twitter direct message. “Until it is accepted in your jurisdiction, relying on it could be hit and miss as a legal tool.”

Ultimately, though, we shouldn’t (and hopefully won’t ever have to) rely heavily on an app to guide us through intimate encounters in the first place.

“Communicating consent is easy!" the EFF’s Galperin said over the phone. "It’s easier than doing anything on the blockchain… I wouldn’t want to have sex with anybody who thinks this is easier than getting consent.”