4 ms·

But the entire point of client-side encryption is to avoid having to trust a server. If you have to trust the server, then there's no reason to do the client-s

by moxie 14y ago

But the entire point of client-side encryption is to avoid having to trust a server. If you have to trust the server, then there's no reason to do the client-side encryption at all. It's just overhead at that point.

RyanZAG 14y ago
Agree completely if the goal was to provide encrypted storage. However, as noted in other comments, this isn't actually the goal. The goal is to create a plausible legal defense against legal threats from the RIAA and similar. If the encryption is done on the server side, Mega can legally be required to make a log of all copyrighted works uploaded to their servers and be liable for distribution. If the file is encrypted before it is uploaded, then Mega cannot physically store a log of copyrighted works. This is pretty major as take-down requests can then only be sent for a single upload. The most that could be done is for a court to publicly order Mega to cease and desist, at which point everyone can move on with no legal liability. This is a piracy platform, not a genuine secure storage. It's fairly clever. Sidenote regarding comment below: I live in Africa, I'm not sure who I trust less out of my bank, the police, or Mega. Probably not Mega!
kretor 14y ago
No, client-side encryption makes sense even if you have to trust the server. When Mega's server gets compromised, the attackers cannot get a user's private keys until he visits Mega's site. Without client-side encryption, attackers could get all the user's keys and thus all their data immediately.
AnthonyMouse 14y ago
> If you have to trust the server, then there's no reason to do the client-side encryption at all. It's just overhead at that point. Think of it as bootstrapping. If they released a service you couldn't use from a browser, probably nobody would use it. But if they release one, even if it isn't as secure as it ought to be, and get millions of users, then someone will write a browser plug in that makes it so you don't have to trust the javascript anymore, and anyone who needs better security will use that. At that point the javascript is irrelevant because no one who needs better security is (or should be) relying on it, but first you have to get to that point. What the javascript becomes is a gateway into the service for people who don't need security and just want to take advantage of 50GB free storage, or who interact with people who have a different threat model. For example, here's a use case: You're a whistleblower. You want to distribute something to the world and you can't allow anyone to know who you are. So you don't use the javascript, you use an open source native client, and you make your upload using TOR or pick your favorite anonymizer. Then Mega has an encrypted copy of what you want to publish, they have no idea what it is. Now all you have to do is post the link and password to a public forum (again using an anonymizer, and possibly from a different country from where you made the upload) so that by the time any third party can even know what it is that you've uploaded, it's available to the world and you're in a safe place. Meanwhile none of the downloaders who don't need protection from anyone has to install any special software because they can use the javascript.

by moxie 14y ago

RyanZAG 14y ago

Agree completely if the goal was to provide encrypted storage. However, as noted in other comments, this isn't actually the goal. The goal is to create a plausible legal defense against legal threats from the RIAA and similar. If the encryption is done on the server side, Mega can legally be required to make a log of all copyrighted works uploaded to their servers and be liable for distribution. If the file is encrypted before it is uploaded, then Mega cannot physically store a log of copyrighted works. This is pretty major as take-down requests can then only be sent for a single upload. The most that could be done is for a court to publicly order Mega to cease and desist, at which point everyone can move on with no legal liability. This is a piracy platform, not a genuine secure storage. It's fairly clever. Sidenote regarding comment below: I live in Africa, I'm not sure who I trust less out of my bank, the police, or Mega. Probably not Mega!

kretor 14y ago

No, client-side encryption makes sense even if you have to trust the server. When Mega's server gets compromised, the attackers cannot get a user's private keys until he visits Mega's site. Without client-side encryption, attackers could get all the user's keys and thus all their data immediately.

AnthonyMouse 14y ago

> If you have to trust the server, then there's no reason to do the client-side encryption at all. It's just overhead at that point. Think of it as bootstrapping. If they released a service you couldn't use from a browser, probably nobody would use it. But if they release one, even if it isn't as secure as it ought to be, and get millions of users, then someone will write a browser plug in that makes it so you don't have to trust the javascript anymore, and anyone who needs better security will use that. At that point the javascript is irrelevant because no one who needs better security is (or should be) relying on it, but first you have to get to that point. What the javascript becomes is a gateway into the service for people who don't need security and just want to take advantage of 50GB free storage, or who interact with people who have a different threat model. For example, here's a use case: You're a whistleblower. You want to distribute something to the world and you can't allow anyone to know who you are. So you don't use the javascript, you use an open source native client, and you make your upload using TOR or pick your favorite anonymizer. Then Mega has an encrypted copy of what you want to publish, they have no idea what it is. Now all you have to do is post the link and password to a public forum (again using an anonymizer, and possibly from a different country from where you made the upload) so that by the time any third party can even know what it is that you've uploaded, it's available to the world and you're in a safe place. Meanwhile none of the downloaders who don't need protection from anyone has to install any special software because they can use the javascript.