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> JS crypto remains better since there exists techniques to verify the crypto, and the server does not receive plaintext. You are giving the plaintext to code

by jbri 15y ago

> JS crypto remains better since there exists techniques to verify the crypto, and the server does not receive plaintext. You are giving the plaintext to code that has (at best) the same trust level as the server itself. What data is it safe to give to that code, that isn't safe to send (in a way that can't be mitm'd) to the server? > That's ridiculous. Integrity checks exist for many crypto-systems, don't perform crypto - they are an extension. I'm not sure what you're saying here - you might want to clarify exactly what you mean. In doing so, perhaps you could tell me why you think "browser plugin validator + untrusted JS crypto code" is more secure or otherwise better than "browser plugin crypto with no JS".

magikarp 15y ago
Don't get me wrong, browser plugin crypto probably works fine, but it's also possible to use a browser plugin to turn untrusted JS crypto code into trusted JS crypto code. The plus side of that is that the crypto code would still work without the plugin.
- jbri 15y ago
  So your answer as to why JS+validator is better than a plugin doing crypto is that "it still appears to work fine even when the system is utterly broken". ... When it comes to security, that is actually a negative.
  - magikarp 15y ago
    Whether you consider it "utterly broken" or not without the validator depends on your trust of the server - similarly to HTTPS, which is vulnerable from the trust standpoint thanks to CA vulnerabilities. Furthermore, it's possible to verify the code manually, although tediously, whereas a CA impersonation is perfectly transparent and very difficult to detect. The validator plugin usually does the job.
    - jbri 15y ago
      ...and your trust of the network itself, unless you're using HTTPS in addition to your ad-hoc solution. And vulnerabilities in the trust chain are not HTTPS vulnerabilities - they are trust chain vulnerabilities. It's straightforward to address them yourself simply by not trusting any CAs you don't trust.
      - magikarp 15y ago
        > unless you're using HTTPS in addition to your ad-hoc solution. Yes, I don't see why not. > It's straightforward to address them yourself simply by not trusting any CAs you don't trust. From that standpoint, we're assuming that everyone with a browser knows what a CA is and discerns between trustworthy CAs. I could equally say that it's straightforward for users to simply review the JavaScript code they don't trust - but the problem is that there exist many users who don't know how to review JavaScript and don't know what a CA is, and will just rely on what their browser tells them (which is where a plugin comes in handy.)
        jbri 15y ago
        Why is a plugin trustworthy where the root CAs are not?
        magikarp 15y ago
        Simply because a plugin can be verified locally at length whereas a compromised CA can issue a fake cert that is very, very difficult to detect.
        jbri 15y ago
        > but the problem is that there exist many users who don't know how to review JavaScript and don't know what a CA is, and will just rely on what their browser tells them (which is where a plugin comes in handy.) > a plugin can be verified locally at length whereas a compromised CA can issue a fake cert that is very, very difficult to detect. Which is it? Either you're claiming that verifying a plugin is easier than not trusting CAs that you don't trust, or you're arguing two completely contrary positions. edit: And this then brings us back to the earlier point, which is why not just use the plugin for crypto in the first place?

by jbri 15y ago

magikarp 15y ago

Don't get me wrong, browser plugin crypto probably works fine, but it's also possible to use a browser plugin to turn untrusted JS crypto code into trusted JS crypto code. The plus side of that is that the crypto code would still work without the plugin.

jbri 15y ago
So your answer as to why JS+validator is better than a plugin doing crypto is that "it still appears to work fine even when the system is utterly broken". ... When it comes to security, that is actually a negative.
- magikarp 15y ago
  Whether you consider it "utterly broken" or not without the validator depends on your trust of the server - similarly to HTTPS, which is vulnerable from the trust standpoint thanks to CA vulnerabilities. Furthermore, it's possible to verify the code manually, although tediously, whereas a CA impersonation is perfectly transparent and very difficult to detect. The validator plugin usually does the job.
  - jbri 15y ago
    ...and your trust of the network itself, unless you're using HTTPS in addition to your ad-hoc solution. And vulnerabilities in the trust chain are not HTTPS vulnerabilities - they are trust chain vulnerabilities. It's straightforward to address them yourself simply by not trusting any CAs you don't trust.
    - magikarp 15y ago
      > unless you're using HTTPS in addition to your ad-hoc solution. Yes, I don't see why not. > It's straightforward to address them yourself simply by not trusting any CAs you don't trust. From that standpoint, we're assuming that everyone with a browser knows what a CA is and discerns between trustworthy CAs. I could equally say that it's straightforward for users to simply review the JavaScript code they don't trust - but the problem is that there exist many users who don't know how to review JavaScript and don't know what a CA is, and will just rely on what their browser tells them (which is where a plugin comes in handy.)
      - jbri 15y ago
        Why is a plugin trustworthy where the root CAs are not?
        magikarp 15y ago
        Simply because a plugin can be verified locally at length whereas a compromised CA can issue a fake cert that is very, very difficult to detect.
        jbri 15y ago
        > but the problem is that there exist many users who don't know how to review JavaScript and don't know what a CA is, and will just rely on what their browser tells them (which is where a plugin comes in handy.) > a plugin can be verified locally at length whereas a compromised CA can issue a fake cert that is very, very difficult to detect. Which is it? Either you're claiming that verifying a plugin is easier than not trusting CAs that you don't trust, or you're arguing two completely contrary positions. edit: And this then brings us back to the earlier point, which is why not just use the plugin for crypto in the first place?