5 ms·

> There is absolutely no way for a customer to verify their claims that the data is not saved or transferred elsewhere. Transparency logs are capable of verify

> There is absolutely no way for a customer to verify their claims that the data is not saved or transferred elsewhere. Transparency logs are capable of verifying that, it's more or less the whole point of them. (Strictly speaking, you can make it arbitrarily expensive to fake it.) Also, if they were "transferring your data elsewhere" it would be a GDPR violation. Ironically wrt your China claim, it would also be illegal in China, which does in fact have privacy laws.

ls612 2y ago
Are transparency logs akin to Certificate Transparency but for signed code? I’ve read through the section a couple times and still don’t fully understand it.
- astrange 2y ago
  Yeah, it's a log of all the software that runs on the server. If you trust the secure boot process then you trust the log describes its contents. If you don't trust the boot process/code signing system then you'd want to do something else, like ask the server to show you parts of its memory on demand in case you catch it lying to you. (Not sure if that's doable here because the server has other people's data on it, which is the whole point.)
  - kfreds 2y ago
    One approach would be a chip design where a remote attestation request issues a hardware interrupt, and then the hardware hashes the contents of memory, more specifically the memory containing the code.
    - astrange 2y ago
      That's not quite enough but yes. (You need to prove that the system is showing you the server your data is present on, and not just showing you an innocuous one and actually processing your data on a different evil one.)
gigel82 2y ago
That makes no sense at all. They control the servers and services entirely; they can choose to emit whatever logs they want into the "transparent logs" and then emit whatever else they don't want into non-transparent logs. Even if they were running open source software with cryptographically verified / reproducible builds, it's still running on their hardware (any component or the OS / kernel or even hardware can be hooked into to exfiltrate unencrypted data). Companies like Apple don't give a crap about GDPR violations (you can look at their "DMA compliance" BS games to see to what extent they're willing to go to skirt regulations in the name of profit).
- davidczech 2y ago
  > they can choose to emit whatever logs they want into the "transparent logs" and then emit whatever else they don't want into non-transparent logs. The log is publicly accessible and append-only, so such an event would not go un-noticed. Not sure what a non-transparent log is.
  - gigel82 2y ago
    Ok, but they write and fully control the closed-source software that appends to the log. How can anyone verify that all the code paths append to the log? I'm pretty sure they can just not append to the log from their ExfiltrateDataForAdvertisment() and ExfiltrateDataForGovernments() functions. Maybe I'm not being clear; transparent logs solve the problem of supply chain attacks (that is, Apple can use the logs to some degree to ensure some 3rd party isn't modifying their code), but I'm trying to say Apple themselves ARE the bad actor, they will exfiltrate customer data for their own profit (to personalize ads, or continue building user profiles, or sell to governments and so on).
    - davidczech 2y ago
      > How can anyone verify that all the code paths append to the log? I'm pretty sure they can just not append to the log from their ExfiltrateDataForAdvertisment() and ExfiltrateDataForGovernments() functions. I think we have different understandings of what the transparency log is utilized for. The log is used effectively as an append-only hash set of trusted software hashes a PCC node is allowed to run, accomplished using Merkle Trees. The client device (iPhone) uses the log to determine if the software measurements from an attestation should be rejected or not. https://security.apple.com/documentation/private-cloud-compute/appendix_transparencylog#Log-integrity-verification https://security.apple.com/documentation/private-cloud-compu...

ls612 2y ago

Are transparency logs akin to Certificate Transparency but for signed code? I’ve read through the section a couple times and still don’t fully understand it.

astrange 2y ago
Yeah, it's a log of all the software that runs on the server. If you trust the secure boot process then you trust the log describes its contents. If you don't trust the boot process/code signing system then you'd want to do something else, like ask the server to show you parts of its memory on demand in case you catch it lying to you. (Not sure if that's doable here because the server has other people's data on it, which is the whole point.)
- kfreds 2y ago
  One approach would be a chip design where a remote attestation request issues a hardware interrupt, and then the hardware hashes the contents of memory, more specifically the memory containing the code.
  - astrange 2y ago
    That's not quite enough but yes. (You need to prove that the system is showing you the server your data is present on, and not just showing you an innocuous one and actually processing your data on a different evil one.)

gigel82 2y ago

That makes no sense at all. They control the servers and services entirely; they can choose to emit whatever logs they want into the "transparent logs" and then emit whatever else they don't want into non-transparent logs. Even if they were running open source software with cryptographically verified / reproducible builds, it's still running on their hardware (any component or the OS / kernel or even hardware can be hooked into to exfiltrate unencrypted data). Companies like Apple don't give a crap about GDPR violations (you can look at their "DMA compliance" BS games to see to what extent they're willing to go to skirt regulations in the name of profit).

davidczech 2y ago
> they can choose to emit whatever logs they want into the "transparent logs" and then emit whatever else they don't want into non-transparent logs. The log is publicly accessible and append-only, so such an event would not go un-noticed. Not sure what a non-transparent log is.
- gigel82 2y ago
  Ok, but they write and fully control the closed-source software that appends to the log. How can anyone verify that all the code paths append to the log? I'm pretty sure they can just not append to the log from their ExfiltrateDataForAdvertisment() and ExfiltrateDataForGovernments() functions. Maybe I'm not being clear; transparent logs solve the problem of supply chain attacks (that is, Apple can use the logs to some degree to ensure some 3rd party isn't modifying their code), but I'm trying to say Apple themselves ARE the bad actor, they will exfiltrate customer data for their own profit (to personalize ads, or continue building user profiles, or sell to governments and so on).
  - davidczech 2y ago
    > How can anyone verify that all the code paths append to the log? I'm pretty sure they can just not append to the log from their ExfiltrateDataForAdvertisment() and ExfiltrateDataForGovernments() functions. I think we have different understandings of what the transparency log is utilized for. The log is used effectively as an append-only hash set of trusted software hashes a PCC node is allowed to run, accomplished using Merkle Trees. The client device (iPhone) uses the log to determine if the software measurements from an attestation should be rejected or not. https://security.apple.com/documentation/private-cloud-compute/appendix_transparencylog#Log-integrity-verification https://security.apple.com/documentation/private-cloud-compu...