mirror of
https://github.com/privacyguides/privacyguides.org.git
synced 2025-09-15 22:48:46 +00:00
Compare commits
7 Commits
security-k
...
sumbitted-
Author | SHA1 | Date | |
---|---|---|---|
dda72ad452
|
|||
7fa7e4b264
|
|||
42ecb644f1
|
|||
3a58ac310f
|
|||
7d3d849474
|
|||
![]() |
16b3e5e16f | ||
![]() |
2dd653b12f |
@@ -86,6 +86,10 @@ authors:
|
|||||||
mastodon:
|
mastodon:
|
||||||
username: blacklight447
|
username: blacklight447
|
||||||
instance: mastodon.social
|
instance: mastodon.social
|
||||||
|
ptrmdn:
|
||||||
|
name: Peter Marsden
|
||||||
|
description: Guest Contributor
|
||||||
|
avatar: https://forum-cdn.privacyguides.net/user_avatar/discuss.privacyguides.net/ptrmdn/288/14291_2.png
|
||||||
sam-howell:
|
sam-howell:
|
||||||
name: Sam Howell
|
name: Sam Howell
|
||||||
description: Guest Contributor
|
description: Guest Contributor
|
||||||
|
BIN
blog/assets/images/multi-party-computation/cover.webp
Normal file
BIN
blog/assets/images/multi-party-computation/cover.webp
Normal file
Binary file not shown.
After Width: | Height: | Size: 891 KiB |
@@ -1,12 +1,13 @@
|
|||||||
---
|
---
|
||||||
date:
|
date:
|
||||||
created: 2025-09-08T18:00:00Z
|
created: 2025-09-08T18:00:00Z
|
||||||
|
updated: 2025-09-15T16:30:00Z
|
||||||
categories:
|
categories:
|
||||||
- News
|
- News
|
||||||
authors:
|
authors:
|
||||||
- em
|
- em
|
||||||
description:
|
description:
|
||||||
Chat Control is back to undermine everyone's privacy. There's an important deadline this Friday on September 12th. We must act now to stop it!
|
Chat Control is back to undermine everyone's privacy. There's an important deadline on October 14th, 2025. We must act now to stop it!
|
||||||
schema_type: ReportageNewsArticle
|
schema_type: ReportageNewsArticle
|
||||||
preview:
|
preview:
|
||||||
cover: blog/assets/images/chat-control-must-be-stopped/chatcontrol-cover.webp
|
cover: blog/assets/images/chat-control-must-be-stopped/chatcontrol-cover.webp
|
||||||
@@ -18,7 +19,7 @@ preview:
|
|||||||
|
|
||||||
<small aria-hidden="true">Illustration: Em / Privacy Guides | Photo: Ramaz Bluashvili / Pexels</small>
|
<small aria-hidden="true">Illustration: Em / Privacy Guides | Photo: Ramaz Bluashvili / Pexels</small>
|
||||||
|
|
||||||
If you've heard of [Chat Control](the-future-of-privacy.md) already, bad news: **it's back**. If you haven't, this is a pressing issue you should urgently learn more about if you value privacy, democracy, and human rights. This is happening **this week**, and **we must act to stop it right now**.<!-- more -->
|
If you've heard of [Chat Control](the-future-of-privacy.md) already, bad news: **it's back**. If you haven't, this is a pressing issue you should urgently learn more about if you value privacy, democracy, and human rights. This is happening **right now**, and **we must act to stop it right now**.<!-- more -->
|
||||||
|
|
||||||
Take a minute to visualize this: Every morning you wake up with a police officer entering your home to inspect it, and staying with you all day long.
|
Take a minute to visualize this: Every morning you wake up with a police officer entering your home to inspect it, and staying with you all day long.
|
||||||
|
|
||||||
@@ -32,7 +33,16 @@ This is an Orwellian nightmare.
|
|||||||
|
|
||||||
## Act now!
|
## Act now!
|
||||||
|
|
||||||
This is happening **this week**. European governments will be finalizing their positions on the regulation proposal on **Friday, September 12th, 2025**.
|
This is happening **right now**. European governments will be finalizing their positions on the regulation proposal on September 12th, and there will be a final vote on **October 14th, 2025**.
|
||||||
|
|
||||||
|
<div class="admonition warning" markdown>
|
||||||
|
<p class="admonition-title">Important: If you are reading this article after September 12th</p>
|
||||||
|
|
||||||
|
Regardless of the outcome on September 12th, the fight isn't over. The next deadline will be the **final vote on October 14th, 2025**.
|
||||||
|
|
||||||
|
If you've missed September 12th, make sure to contact your representatives **right now** to tell them to **oppose Chat Control** on October 14th.
|
||||||
|
|
||||||
|
</div>
|
||||||
|
|
||||||
- ==If you are not located in Europe==: Keep reading, this will affect you too.
|
- ==If you are not located in Europe==: Keep reading, this will affect you too.
|
||||||
|
|
||||||
@@ -41,11 +51,11 @@ This is happening **this week**. European governments will be finalizing their p
|
|||||||
- If you are located in Europe: You must **act now** to stop it.
|
- If you are located in Europe: You must **act now** to stop it.
|
||||||
|
|
||||||
<div class="admonition question" markdown>
|
<div class="admonition question" markdown>
|
||||||
<p class="admonition-title">How to stop this? Contact your MEPs before September 12th</p>
|
<p class="admonition-title">How to stop this? Contact your MEPs today</p>
|
||||||
|
|
||||||
Use this [**website**](https://fightchatcontrol.eu/) to easily contact your government representatives before September 12th, and tell them they should **oppose Chat Control**. Even if your country already opposes Chat Control, contact your representatives to tell them you are relieved they oppose, and support them in this decision to protect human rights. This will help reinforce their position.
|
Use this [**website**](https://fightchatcontrol.eu/) to easily contact your government representatives, and tell them they should **oppose Chat Control**. Even if your country already opposes Chat Control, contact your representatives to tell them you are relieved they oppose, and support them in this decision to protect human rights. This will help reinforce their position.
|
||||||
|
|
||||||
But if your country *supports* Chat Control, or is *undecided*, **it is vital that you contact your representatives before this deadline**. To support your point, you can share this article with them or one of the many great [resources](#resources-to-learn-more-and-fight-for-human-rights) listed at the end.
|
But if your country *supports* Chat Control, or is *undecided*, **it is vital that you contact your representatives as soon as possible**. To support your point, you can share this article with them or one of the many great [resources](#resources-to-learn-more-and-fight-for-human-rights) listed at the end.
|
||||||
|
|
||||||
At the time of this writing, the list of countries to contact is:
|
At the time of this writing, the list of countries to contact is:
|
||||||
|
|
||||||
@@ -144,11 +154,11 @@ There are many things we can do as a society to increase protections for childre
|
|||||||
|
|
||||||
### Mislabelling children as criminals
|
### Mislabelling children as criminals
|
||||||
|
|
||||||
First, this automated system is flawed in many ways, and the false-positive rate would likely be high. But let's imagine that, magically, the system could flag CSAM at an accuracy rate of 99%. This still means 1% of reports would be false. Expanded to the size of Europe Union's population of approximately 450 million people, exchanging likely billions of messages and files every day, this still means millions could be falsely tagged as sexual predators, with all the [consequences](https://www.republik.ch/2022/12/08/die-dunklen-schatten-der-chatkontrolle) this implies.
|
First, this automated system is flawed in many ways, and the false-positive rate would likely be high. But let's imagine that, magically, the system could flag CSAM at an accuracy rate of 99%. This still means 1% of reports would be false. Expanded to the size of European Union's population of approximately 450 million people, exchanging likely billions of messages and files every day, this still means millions could be falsely tagged as sexual predators, with all the [consequences](https://www.republik.ch/2022/12/08/die-dunklen-schatten-der-chatkontrolle) this implies.
|
||||||
|
|
||||||
Worse, the Swiss federal police reported that currently about 80% of all automated reports received were [false-positives](https://www.patrick-breyer.de/en/posts/chat-control/#WhatYouCanDo). This means in reality, the error rate is likely far higher than 1%, and actually closer to an **80% error rate**. Of the approximate 20% of positive reports, in Germany, over 40% of investigations initiated [targeted children](https://www.polizei-beratung.de/aktuelles/detailansicht/straftat-verbreitung-kinderpornografie-pks-2022/) themselves.
|
Worse, the Swiss federal police reported that currently about 80% of all automated reports received were [false-positives](https://www.patrick-breyer.de/en/posts/chat-control/#WhatYouCanDo). This means in reality, the error rate is likely far higher than 1%, and actually closer to an **80% error rate**. Of the approximate 20% of positive reports, in Germany, over 40% of investigations initiated [targeted children](https://www.polizei-beratung.de/aktuelles/detailansicht/straftat-verbreitung-kinderpornografie-pks-2022/) themselves.
|
||||||
|
|
||||||
Sometimes, flagged content is simply teenagers innocently sexting each other consensually. Not only would they be wrongly tagged as criminals under Chat Control, but they'd be triggering an investigation that would expose their intimate photos to others.
|
Sometimes, flagged content is simply teenagers innocently sexting each other consensually. Not only would they be wrongly tagged as criminals under Chat Control, but they'd be triggering an investigation that would expose their intimate photos to some faceless officers or tech employees working on the system.
|
||||||
|
|
||||||
Even in a magical world where Chat Control AI is 99% accurate, it would still wrongly tag and **expose sensitive data from millions of children**. In reality, no AI system is even remotely close to this accuracy level, and proprietary algorithms are usually opaque black boxes impossible to audit transparently. The number of children Chat Control would harm, and likely traumatize for life, would be disastrous.
|
Even in a magical world where Chat Control AI is 99% accurate, it would still wrongly tag and **expose sensitive data from millions of children**. In reality, no AI system is even remotely close to this accuracy level, and proprietary algorithms are usually opaque black boxes impossible to audit transparently. The number of children Chat Control would harm, and likely traumatize for life, would be disastrous.
|
||||||
|
|
||||||
@@ -243,7 +253,7 @@ Even if the landscape seems dismal, **the battle isn't over**. There are many th
|
|||||||
|
|
||||||
### For Europeans, specifically
|
### For Europeans, specifically
|
||||||
|
|
||||||
- Contact your country representatives **TODAY**. Contact them before this Friday, September 12th, 2025. The group Fight Chat Control has put together an [**easy tool**](https://fightchatcontrol.eu/#contact-tool) making this quick with only a few clicks.
|
- Contact your country representatives **TODAY**. The group Fight Chat Control has put together an [**easy tool**](https://fightchatcontrol.eu/#contact-tool) making this quick with only a few clicks.
|
||||||
|
|
||||||
- After September 12th, the battle isn't over. Although governments will finalize their positions on that day, the final vote happens on **October 14th, 2025**. If you missed the September 12th deadline, keep contacting your representatives anyway.
|
- After September 12th, the battle isn't over. Although governments will finalize their positions on that day, the final vote happens on **October 14th, 2025**. If you missed the September 12th deadline, keep contacting your representatives anyway.
|
||||||
|
|
||||||
@@ -251,7 +261,7 @@ Even if the landscape seems dismal, **the battle isn't over**. There are many th
|
|||||||
|
|
||||||
### For Everyone, including Europeans
|
### For Everyone, including Europeans
|
||||||
|
|
||||||
- Talk about Chat Control on social media often, especially this week. Make noise online. Use the hashtags #ChatControl and #StopScanningMe to help others learn more about the opposition movement.
|
- Talk about Chat Control on social media often, especially this month. Make noise online. Use the hashtags #ChatControl and #StopScanningMe to help others learn more about the opposition movement.
|
||||||
|
|
||||||
- Share informative [videos and memes](#resources-to-learn-more-and-fight-for-human-rights) about Chat Control. Spread the word in various forms.
|
- Share informative [videos and memes](#resources-to-learn-more-and-fight-for-human-rights) about Chat Control. Spread the word in various forms.
|
||||||
|
|
||||||
@@ -296,13 +306,8 @@ We need your help to fight this. For democracy, for privacy, and for all other h
|
|||||||
|
|
||||||
- [Follow **Fight Chat Control** on Mastodon for updates](https://mastodon.social/@chatcontrol)
|
- [Follow **Fight Chat Control** on Mastodon for updates](https://mastodon.social/@chatcontrol)
|
||||||
|
|
||||||
<div class="admonition warning" markdown>
|
---
|
||||||
<p class="admonition-title">Important Note: If you are reading this article after September 12th</p>
|
|
||||||
|
|
||||||
Regardless of the outcome on Friday, the fight isn't over after September 12th. The next deadline will be the **final vote on October 14th, 2025**.
|
**Update (9/15):** Added modifications related to the second important deadline for action, on October 14th.
|
||||||
|
|
||||||
If you've missed September 12th, make sure to contact your representatives **right now** to tell them to **oppose Chat Control** on October 14th.
|
**Update (9/8):** Added clarification about what Chat Control is for readers unfamiliar with it.
|
||||||
|
|
||||||
</div>
|
|
||||||
|
|
||||||
Update (9/8): Added clarification about what Chat Control is for readers unfamiliar with it.
|
|
||||||
|
155
blog/posts/multi-party-computation.md
Normal file
155
blog/posts/multi-party-computation.md
Normal file
@@ -0,0 +1,155 @@
|
|||||||
|
---
|
||||||
|
date:
|
||||||
|
created: 2025-09-15T17:30:00Z
|
||||||
|
categories:
|
||||||
|
- Explainers
|
||||||
|
authors:
|
||||||
|
- fria
|
||||||
|
tags:
|
||||||
|
- Privacy Enhancing Technologies
|
||||||
|
schema_type: BackgroundNewsArticle
|
||||||
|
description: Learn about Secure Multi-Party Computation and how it can be used to solve real-world privacy problems.
|
||||||
|
---
|
||||||
|
# What is Multi-Party Computation?
|
||||||
|
|
||||||
|

|
||||||
|
|
||||||
|
<small aria-hidden="true">Illustration: Jordan Warne / Privacy Guides</small>
|
||||||
|
|
||||||
|
We know how to secure data in storage using E2EE, but is it possible to ensure data privacy even while processing it server-side? This is the first in a [series](../tags.md/#tag:privacy-enhancing-technologies) of articles I'll be writing covering the privacy-enhancing technologies being rolled out.<!-- more -->
|
||||||
|
|
||||||
|
## History
|
||||||
|
|
||||||
|
In a seminal [paper](https://dspace.mit.edu/bitstream/handle/1721.1/148953/MIT-LCS-TM-125.pdf?sequence=1) called "Mental Poker" by Adi Shamir, Ronald L. Rivest, and Leonard M. Adleman from 1979, the researchers attempt to demonstrate a way of playing poker over a distance using only messages and still have it be a fair game.
|
||||||
|
|
||||||
|
To explain, fan favorites Alice and Bob will make a return. First, Bob encrypts all the cards with his key, then sends them to Alice. Alice picks five to deal back to Bob as his hand, then encrypts five with her own key and sends those to Bob as well. Bob removes his encryption from all ten cards and sends Alice's cards back to her.
|
||||||
|
|
||||||
|
<div style="position: relative; padding-top: 56.25%;"><iframe title="Mental Poker Animation" width="100%" height="100%" src="https://neat.tube/videos/embed/k5jMvrTPLx5VcgzNq3ej1B?title=0" frameborder="0" allowfullscreen="" sandbox="allow-same-origin allow-scripts allow-popups allow-forms" style="position: absolute; inset: 0px;"></iframe></div>
|
||||||
|
|
||||||
|
Notice that Bob needs to be able to remove his encryption *after* Alice has applied hers. This commutative property is important for the scheme to work.
|
||||||
|
|
||||||
|
This early scheme is highly specialized for this task and not applicable to different situations.
|
||||||
|
|
||||||
|
### Secure Two-Party Computation
|
||||||
|
|
||||||
|
Alice and Bob have struck it rich! They're both millionaires, but they want to be able to see who has more money without revealing exactly how much they have to each other.
|
||||||
|
|
||||||
|
Luckily, we can use **Multi-Party Computation** (**MPC**) to solve this "Millionaire's Problem," using a method invented by Andrew Yao called *garbled circuits*. Garbled circuits allow us to use MPC for any problem as long as it can be represented as a boolean circuit, i.e. a set of logic gates such as `AND` `OR` `XOR` etc.
|
||||||
|
|
||||||
|
### Garbled Circuits
|
||||||
|
|
||||||
|
We can split the two parties into an "Evaluator" and a "Generator". The Generator will be responsible for setting up the cryptography that'll be used, and the Evaluator will actually perform the computation.
|
||||||
|
|
||||||
|
We start by making the truth table for our inputs. In order to hide the values of the truth table, we assign each input a different label. Importantly, we need to assign a different label for each input, so 1 will not be represented by the same label for each. We also need to shuffle the order of the rows, so the values can't be inferred from that.
|
||||||
|
|
||||||
|
We can still tell what the value is based on knowing the type of logic gate. For example, an `AND` gate would only have one different output, so you could infer that output is 1 and the others are 0. To fix this, we can encrypt the rows using the input labels as keys, so only the correct output can be decrypted.
|
||||||
|
|
||||||
|
We still have a problem, though: how can the Evaluator put in their inputs? Asking for both labels would allow them to decrypt more than one output, and giving their input would break the whole point. The solution is something called "Oblivious Transfer".
|
||||||
|
|
||||||
|
The solution is for the Evaluator to generate two public keys, one of which they have the private key for. The Generator encrypts the two labels for the Evaluator's inputs using the provide public keys and sends them back. Since the Generator only has a private key for one of the labels, they will decrypt the one they want. The Generator puts the labels in order so that the Evaluator can choose which one they want to decrypt. This method relies on the Evaluator not to send multiple keys that can be decrypted. Because some trust is required, this protocol is considered "semi-honest".
|
||||||
|
|
||||||
|
There's a good explainer for Yao's garbled circuits [here](https://lcamel.github.io/MPC-Notes/story-en-US.html) if you're interested in a step-by-step walkthrough.
|
||||||
|
|
||||||
|
### Birth of Multi-Party Computation
|
||||||
|
|
||||||
|
Multi-Party Computation was solidified with the [research](https://dl.acm.org/doi/pdf/10.1145/28395.28420) of Oded Goldreich, Silvio Micali, and Avi Wigderson and the GMW paradigm (named after the researchers, similar to how RSA is named).
|
||||||
|
|
||||||
|
#### More Than Two Parties
|
||||||
|
|
||||||
|
Yao's protocol was limited to two parties. The GMW paradigm expanded the protocol to be able to handle any number of parties and can handle actively malicious actors as long as the majority are honest.
|
||||||
|
|
||||||
|
#### Secret Sharing
|
||||||
|
|
||||||
|
The GMW paradigm relies on secret sharing which is a method of splitting private information like a cryptographic key into multiple parts such that it will only reveal the secret if the shares are combined. The GMW protocol uses additive secret sharing, which is quite simple. You come up with a secret number, say 123, and you split it up into however many other numbers you want.
|
||||||
|
|
||||||
|
`99 + 24 = 123`
|
||||||
|
|
||||||
|
You distribute each number to a participant and add them all together to get the original secret. While simple, it doesn't play well with multiplication operations.
|
||||||
|
|
||||||
|
#### Zero-Knowledge Proofs
|
||||||
|
|
||||||
|
The GMW paradigm introduced protections against malicious adversaries, powered by zero-knowledge proofs (ZKP). ZKP allow one party to convince another party a statement is true without revealing any other information than the fact that the statement is true. The concept of ZKP was first introduced in a [paper](https://dl.acm.org/doi/pdf/10.1145/22145.22178) from 1985 by Shafi Goldwasser, Silvio Micali, and Charles Rackoff.
|
||||||
|
|
||||||
|
A humorous paper titled *[How to Explain Zero-Knowledge Protocols to Your Children](https://pages.cs.wisc.edu/~mkowalcz/628.pdf)* gives a storybook explanation of how they work (who says academic papers can't be fun?).
|
||||||
|
|
||||||
|
The main crux revolves around probability: if a party knows the proper way to get a result, they should be able to reliably get the correct answer.
|
||||||
|
|
||||||
|
To borrow the cave explanation, imagine Alice and Bob have taken up cave exploration. They've found a cave in the shape of a loop with a magic door connecting each entrance together and Alice claims to know how to open it. However, she doesn't want Bob to know the secret to open the door.
|
||||||
|
|
||||||
|
Alice, acting as the "Prover" goes into the cave. Bob, the "Verifier", stays outside and yells which side of the cave Alice should come out of. They repeat this many times. If Alice can reliably make it out of the correct side of the cave, then she must know how to open the magic door.
|
||||||
|
|
||||||
|
### BGW Protocol
|
||||||
|
|
||||||
|
While the GMW protocol was a huge leap forward for MPC, there were still huge limitations. The garbled circuit protocol is limited to boolean logic gates which makes implementing many different common operations much more difficult. It also requires communication for every single gate, which is highly inefficient.
|
||||||
|
|
||||||
|
The researchers Michael Ben-Or, Shafi Goldwassert, and Avi Wigderson in their paper *[Completeness Theorems for Non-Cryptographic Fault-Tolerant Distributed Computation](https://dl.acm.org/doi/pdf/10.1145/62212.62213)* made several advancements in the efficiency and robustness of MPC, moving it closer to being practical to use in the real world.
|
||||||
|
|
||||||
|
#### Arithmetic Circuits
|
||||||
|
|
||||||
|
Instead of boolean circuits, the BGW protocol uses arithmetic circuits. These allow for easier mathematical operations like multiplication and addition instead of being limited to logic gates on individual bits. This makes a huge difference in the amount of communication between parties and thus the efficiency of the protocol.
|
||||||
|
|
||||||
|
#### Shamir's Secret Sharing
|
||||||
|
|
||||||
|
The BGW protocol utilizes [Shamir's Secret Sharing](https://web.mit.edu/6.857/OldStuff/Fall03/ref/Shamir-HowToShareASecret.pdf), which relies on polynomials instead of addition. This allows for more efficiency in multiplication and allows for setting a threshold where only a certain number of shares need to be present in order to reconstruct the secret.
|
||||||
|
|
||||||
|
#### Less Communication
|
||||||
|
|
||||||
|
The BGW protocol doesn't require as much communication between parties, partly thanks to its use of Shamir's secret sharing which works well with arithmetic operations.
|
||||||
|
|
||||||
|
Additionally, it doesn't require Oblivious Transfer or zero-knowledge proofs. Its use of Shamir's secret sharing and error correction codes instead provides the same properties in a more efficient way.
|
||||||
|
|
||||||
|
### Fairplay
|
||||||
|
|
||||||
|
The field was further advanced by the introduction of the [Fairplay](https://www.cs.huji.ac.il/w~noam/FairplayMP.pdf) system.
|
||||||
|
|
||||||
|
Up until this paper, MPC was limited to boolean circuits or arithmetic circuits: not exactly friendly if you're a programmer that's used to using higher level languages. Fairplay introduces a compiler, SFDL, which can compile higher level languages to boolean circuits and then securely computes the circuit.
|
||||||
|
|
||||||
|
Fairplay also brings some advancements in efficiency. It utilizes constant rounds, with a fixed 8 rounds, reducing the communication overhead. It also uses the free XOR technique so that encryption operations don't have to be performed on XOR gates, improving efficiency.
|
||||||
|
|
||||||
|
### Real-World Usage
|
||||||
|
|
||||||
|
As MPC saw gradual optimizations and improvements, it grew from an interesting thought experiment to something that could have real-world uses.
|
||||||
|
|
||||||
|
#### Danish Sugar Beet Auction
|
||||||
|
|
||||||
|
The first instance of MPC being used in a real-world scenario wouldn't occur until 2008.
|
||||||
|
|
||||||
|
Denmark's sugar beet industry faced a problem: with the EU significantly reducing its financial support for sugar beet production, they needed to figure out what price the thousands of sugar beet farmers were willing to sell at, and which price the company that bought all the sugar beets would be willing to buy them at, a so-called "double auction" where the buyer and seller figure out the **market clearing price**, or the price at which demand meets supply most effectively.
|
||||||
|
|
||||||
|
But who should be in charge of the auction? Farmers don't want to trust Danisco with their bids as it reveals information about each individual farmer's business. The farmers can't be in charge of it because they don't trust each other. They could use an external consulting firm, but then the entire operation would rely on that one firm's confidentiality and the reliability of their tools.
|
||||||
|
|
||||||
|
The [solution](https://a.storyblok.com/f/266767/x/e4c85ffa34/mpc-goes-live_whitepaper_2008-068.pdf) was to use a "virtual auctioneer" that relied on MPC to fairly carry the auction out.
|
||||||
|
|
||||||
|
It relied on three servers, with one representing each party: Danisco, DKS (the Danish sugar beet growers association), and The SIMAP project (Secure Information Management and Processing, a project sponsored by the Danish National Research Agency).
|
||||||
|
|
||||||
|
The solution was so successful that it was used every year until 2015 when it was no longer needed. A survey of the farmers found that the vast majority found the system simplified the process of trading contracts and that they were satisfied with the level of confidentiality it provided.
|
||||||
|
|
||||||
|
The first test run of MPC was a massive success and the potential was now proven.
|
||||||
|
|
||||||
|
#### The Boston Women's Workforce Council
|
||||||
|
|
||||||
|
In 2016, the [Boston Women's Workforce Council](https://www.boston.gov/sites/default/files/document-file-09-2017/bwwcr-2016-new-report.pdf) worked with 69 companies to investigate if women are paid the same as men.
|
||||||
|
|
||||||
|
Using MPC, the companies were able to process their data without revealing the actual wages of any employees. The wage data of 112,600 employees was collected, representing about 11% of the Greater Boston workforce.
|
||||||
|
|
||||||
|
You can read their detailed findings in the report, but they found that women were indeed being paid less than men: 77 cents for every dollar a man makes on average.
|
||||||
|
|
||||||
|
It was reported in 2023 that thanks to this data, the Boston Women's Workforce Council was able to reduce the wage gap by 30%.
|
||||||
|
|
||||||
|
#### Allegheny County
|
||||||
|
|
||||||
|
In 2018, Allegheny County Department of Human Services partnered with the [Bipartisan Policy Center](https://bipartisanpolicy.org/press-release/bpc-partners-with-allegheny-county-on-new-privacy-preserving-data-project/) to implement MPC, allowing for private and secure sharing of county data on services to the homeless, behavioral health services, causes and incidence of mortality, family interventions, and incarceration.
|
||||||
|
|
||||||
|
The experiment was considered a success, with a recommendation from the U.S. Commission on Evidence-Based Policymaking to further explore the use of MPC.
|
||||||
|
|
||||||
|
## MPC Today
|
||||||
|
|
||||||
|
Today, the [MPC Alliance](https://www.mpcalliance.org) represents a collective of companies that have come together to advance the use of MPC.
|
||||||
|
|
||||||
|
MPC is used for everything from [cryptocurrency](https://www.coinbase.com/learn/wallet/what-is-a-multi-party-computation-mpc-wallet) to HIPAA-compliant [medical](https://pmc.ncbi.nlm.nih.gov/articles/PMC6658266/) uses. There are ongoing efforts to [standardize](https://csrc.nist.gov/projects/threshold-cryptography) it from organizations like NIST, although it's a difficult proposition due to the sheer variation in MPC protocols and use cases.
|
||||||
|
|
||||||
|
There's been research into using MPC for secure and [verifiably fair](https://eprint.iacr.org/2014/075.pdf) [electronic voting](https://arxiv.org/html/2205.10580v4), something that's much needed as countries move toward [electronic voting](https://worldpopulationreview.com/country-rankings/electronic-voting-by-country). It's important to not completely dismiss the march of technology, but these things should be implemented with the utmost caution and scientific rigor. I feel that implementing black-box electronic voting without open and provably secure technologies like MPC is irresponsible and endangers elections.
|
||||||
|
|
||||||
|
MPC acts as an essential privacy tool in the toolbox. It intersects with other PETs like homomorphic encryption, a method of encrypting data in such a way that operations can still be performed on it without revealing the unencrypted data.
|
||||||
|
|
||||||
|
MPC is just one tool among many that's reshaping the privacy landscape. I'm excited to see how it's used in the future and what new advancements it unlocks.
|
@@ -91,7 +91,7 @@ Developed and hosted by *XWiki* in Paris, France, **CryptPad** is a complete onl
|
|||||||
|
|
||||||
<div class="admonition recommendation" markdown>
|
<div class="admonition recommendation" markdown>
|
||||||
|
|
||||||
{ align=right }
|
{ align=right }
|
||||||
|
|
||||||
**Nextcloud** is a suite of free and open-source client-server software for creating your own file hosting services on a private server you control.
|
**Nextcloud** is a suite of free and open-source client-server software for creating your own file hosting services on a private server you control.
|
||||||
|
|
||||||
|
61
blog/posts/the-fight-for-privacy-after-death.md
Normal file
61
blog/posts/the-fight-for-privacy-after-death.md
Normal file
@@ -0,0 +1,61 @@
|
|||||||
|
---
|
||||||
|
date:
|
||||||
|
created: 2025-09-16T18:00:00Z
|
||||||
|
categories:
|
||||||
|
- Opinion
|
||||||
|
authors:
|
||||||
|
- ptrmdn
|
||||||
|
description: In 2020, London police failed to save two sisters in life, then violated their privacy in death. This is a call to arms for posthumous privacy rights.
|
||||||
|
schema_type: OpinionNewsArticle
|
||||||
|
---
|
||||||
|
# Ghosts in the Machine: The Fight for Privacy After Death
|
||||||
|
|
||||||
|
In the early hours of 6 June 2020, Nicole Smallman and her sister Bibaa had just finished celebrating Bibaa’s birthday with friends in a park in London. Alone and in the dark, they were [fatally and repeatedly stabbed](https://en.wikipedia.org/wiki/Murders_of_Bibaa_Henry_and_Nicole_Smallman) 36 times.<!-- more -->
|
||||||
|
|
||||||
|
But the police didn’t just fail them in life – they failed them in death too. PC Deniz Jaffer and PC Jamie Lewis, both of the Metropolitan Police, [took selfies](https://www.theguardian.com/uk-news/2021/dec/06/two-met-police-officers-jailed-photos-murdered-sisters-deniz-jaffer-jamie-lewis-nicole-smallman-bibaa-henry) with the dead bodies of the victims, posting them on a WhatsApp group. And no privacy laws prevented them from doing so.
|
||||||
|
|
||||||
|
This horrific case is just one in the murky, often sinister realm of posthumous privacy. In the UK, Europe, and across the world, privacy protections for the dead are at best a rarity – and at worst, a deep moral and societal failing that we cannot and must not accept.
|
||||||
|
|
||||||
|
Let’s take a step back. The case of the Smallmans starkly draws attention to the denial in death of guarantees to the living. Reading this blog, you are no doubt aware that the UK and Europe have firm privacy protections in *The General Data Protection Regulation* (GDPR) and Article 8 of the *European Convention on Human Rights* (ECHR). But the picture elsewhere is less clear, with a challenging patchwork of laws and regional statutes the only protection for those in the US and much of the rest of the world. And once you die? Almost universally, these protections [immediately cease](https://gdpr-info.eu/recitals/no-27/).
|
||||||
|
|
||||||
|
Here the problem begins. This abrupt collapse in privacy rights leaves the deceased and their families, like the Smallman family, newly vulnerable – and at a time when they are already utterly broken.
|
||||||
|
|
||||||
|
In the absence of law comes the pursuit of it, against a backdrop of flagrant privacy violations. What this pursuit means, in practical terms, is that two primary categories of posthumous privacy dominate legal debate: the medical, where the law has intervened tentatively, and the digital, where it simply hasn’t kept up.
|
||||||
|
|
||||||
|
Medical protections are tentative because of piecemeal development. Typically involving legal workarounds, they offer rare precedent for what might happen to your digital ghosts now and in the future, with the only clear trend being a reluctance to protect.
|
||||||
|
|
||||||
|
That said, the US is one country that has taken measures to protect the medical privacy of the dead. The *Health Insurance Portability and Accountability Act* (HIPAA) dictates that 50 years of protection must be given to your personally identifiable medical information after you die. Except there’s a catch. State laws also apply, and state laws differ. In Colorado, Louisiana, and many others, its efficacy is severely challenged by laws dictating the mandatory release of information regarded as public – including autopsy reports and even [your genetic information](http://dx.doi.org.ezp.lib.cam.ac.uk/10.1177/1073110516654124).
|
||||||
|
|
||||||
|
In lieu of any protections, surviving relatives in Europe have found some success claiming that their own Article 8 rights – that ECHR right to privacy – have been violated through disclosures or inspections related to their deceased.
|
||||||
|
|
||||||
|
In one case, Leyla Polat, an Austrian national, suffered the awful death of her son just two days after birth following a cerebral hemorrhage. The family refused a post-mortem examination, wanting to bury their child in accordance with Muslim beliefs; but doctors insisted it take place, covertly removing his internal organs and filling the hollows with cotton wool. When this was discovered during the funeral rites, the boy had to be buried elsewhere, and without ceremony. After several court cases and appeals, The European Court of Human Rights [found](https://hudoc.echr.coe.int/rum#%7B%22itemid%22:%5B%22002-13361%22%5D%7D) that Leyla’s Article 8 and 9 rights had been violated.
|
||||||
|
|
||||||
|
As an aside – Stalin’s grandson [tried the same Article 8 route](https://hudoc.echr.coe.int/eng#%7B%22itemid%22:%5B%22001-150568%22%5D%7D) in relation to reputational attacks on his grandfather, reflecting attempts to apply the workaround more widely.
|
||||||
|
|
||||||
|
It’s not that there hasn’t been some progress. The fundamental problem is that protections – already sparse – are only as good as their material and geographic scopes, their interactions with other laws, and how they are interpreted in a court. Nowhere is this more apparent than in the case of the Smallman sisters. Judge Mark Lucraft KC [found](https://www.judiciary.uk/wp-content/uploads/2022/07/R-v-Jaffer-Lewis-sentencing-061221.pdf) that PCs Jaffer and Lewis, in taking selfies with the murdered victims, had:
|
||||||
|
|
||||||
|
> *“…wholly disregarded the privacy of the two victims of horrific violence and their families for what can only have been some cheap thrill, kudos, a kick or some form of bragging right by taking images and then passing them to others.”*
|
||||||
|
|
||||||
|
Yet this acknowledgement of privacy violation is precisely just that. The crime the officers committed was misconduct in public office; they were not convicted on the basis of privacy law. That sense of progress – that we might be beginning to recognize the importance of posthumous privacy – has all but gone out of the window.
|
||||||
|
|
||||||
|
That does not leave your digital privacy in a good place. Whatever little protection you may be able to tease out for our medical privacy far, far exceeds the control you have over your virtual ghosts. And with AI just about everywhere, the prospects for your data after death are terrifying.
|
||||||
|
|
||||||
|
We’ve already established that data protections for the living – such as GDPR – expire at death. The simple reality is that dying places your data at the mercy of large technology corporations - and their dubious afterlife tools.
|
||||||
|
|
||||||
|
Even if you trust such tools to dispose of or act on our data, there is a disconnect between demand and take-up. A [study of UK nationals](https://www.tandfonline.com/doi/full/10.1080/13600869.2025.2506164#abstract) found a majority that wanted their data deleted at death were unaware of the tools, with large tech companies unwilling to share any details on their uptake. Reassuring stuff.
|
||||||
|
|
||||||
|
But the reality is, you shouldn’t. You’ll recall that [deletion doesn’t usually mean deletion](https://www.privacyguides.org/en/basics/account-deletion/) – and after death, even GDPR can’t force big tech to delete the data of those lucky enough to have benefited from it. Account deleted or not, our ghosts will all be stuck in the machine.
|
||||||
|
|
||||||
|
Recent reports have acknowledged dire possibilities. Almost worldwide, you can [legally train AI models on the data of a deceased person](https://www.reuters.com/article/world/data-of-the-dead-virtual-immortality-exposes-holes-in-privacy-laws-idUSKBN21Z0NE/) and recreate them in digital form – all without their prior consent. Organizations exist purely to scour your social media profiles and activity for this exact purpose. Your ghost could be used to generate engagement against your will, disclosing what you tried to hide.
|
||||||
|
|
||||||
|
You may ask: why should the law care? Why indeed, when it deems we [cannot be harmed](https://doi.org/10.1093/acprof:oso/9780199607860.003.0003) after death. To argue thus is to miss the point. A lack of privacy after death harms the living, often in ways others cannot see. The effect of [post-mortem anxiety](https://www.tandfonline.com/doi/full/10.1080/17577632.2024.2438395#d1e120) is a real one that deeply troubles individuals wishing to keep a part of them hidden from public – or even family – view, whether it be it an [illicit affair](https://www.cardozoaelj.com/wp-content/uploads/2011/02/Edwards-Galleyed-FINAL.pdf) or whatever else. Revelation at the point of death can be just as harmful to those still alive.
|
||||||
|
|
||||||
|
There is cause for optimism. Article 85 of the *French Data Protection Act* allows you to include [legally enforceable demands concerning your personal data](https://www.cnil.fr/fr/la-loi-informatique-et-libertes#article85) in your will. This is truly a landmark piece of legislation by the French that indicates what the global direction of travel should be, and what we should ultimately demand: protections for the dead, by the dead.
|
||||||
|
|
||||||
|
But even more urgently, we must demand that governments across the world introduce even the most basic legal framework for post-mortem privacy that protects you, your family, and community from egregious harm.
|
||||||
|
|
||||||
|
The Smallmans deserved dignity – and so does everyone else in death. The law must catch up.
|
||||||
|
|
||||||
|
---
|
||||||
|
|
||||||
|
*This article hasn’t even begun to scratch the surface of the complexity of post-mortem privacy, and there are innumerable relevant cases and laws that simply wouldn’t fit. If the topic has caught your interest, and you’d like to dig in more, [this white paper](https://doi.org/10.1016/j.clsr.2022.105737) by Uta Kohl is a good starting point.*
|
Reference in New Issue
Block a user