3 ms·

Though with TPM/full drive encryption you can have a box you own hosted by a third party but that third party cannot "open".

by cm2187 5y ago

KirillPanov 5y ago
What was the most popular TPM chip for many years had a broken RSA key generator. It produced private keys that could be cracked with $76 worth of computing power: https://www.bleepingcomputer.com/news/security/tpm-chipsets-generate-insecure-rsa-keys-multiple-vendors-affected/ https://www.bleepingcomputer.com/news/security/tpm-chipsets-... https://crocs.fi.muni.cz/public/papers/rsa_ccs17 https://crocs.fi.muni.cz/public/papers/rsa_ccs17 It is really hard to see this as anything other than a bugdoor. My laptop has this TPM chip. I am really glad I never used it, and even went so far as to disable support for it when I built my coreboot image. Products sold with the buzzword "trusted" are a magnet for this sort of garbage. They've painted a "please bugdoor me" target on their back. The only thing you can hope to trust is general-purpose computing devices, with a large market, that obey their owner. Unfortunately it is increasingly difficult to find those.
caeril 5y ago
As long as it's running, anyone can exfiltrate your key material from SDRAM. And even for a few minutes after it's running, if they can dump them in LN2 quickly enough. There are kludgy schemes to make this harder, like Schneier's Boojum, but in the end your attacker just needs enough resources and patience. Most FDE schemes don't run crypto ops on the TPM itself - key derivation occurs there, then the results are cached in RAM ( or sometimes, protected CPU registers, in which case they may be able to inject privileged code into the kernel address space? ). LUKS on a colo will probably protect you if you're a fentanyl distributor or movie pirate. Probably not if you're a terrorist or a high-value nation-state target.

Though with TPM/full drive encryption you can have a box you own hosted by a third party but that third party cannot "open".

by cm2187 5y ago

Though with TPM/full drive encryption you can have a box you own hosted by a third party but that third party cannot "open".

KirillPanov 5y ago

What was the most popular TPM chip for many years had a broken RSA key generator. It produced private keys that could be cracked with $76 worth of computing power: https://www.bleepingcomputer.com/news/security/tpm-chipsets-generate-insecure-rsa-keys-multiple-vendors-affected/ https://www.bleepingcomputer.com/news/security/tpm-chipsets-... https://crocs.fi.muni.cz/public/papers/rsa_ccs17 https://crocs.fi.muni.cz/public/papers/rsa_ccs17 It is really hard to see this as anything other than a bugdoor. My laptop has this TPM chip. I am really glad I never used it, and even went so far as to disable support for it when I built my coreboot image. Products sold with the buzzword "trusted" are a magnet for this sort of garbage. They've painted a "please bugdoor me" target on their back. The only thing you can hope to trust is general-purpose computing devices, with a large market, that obey their owner. Unfortunately it is increasingly difficult to find those.

caeril 5y ago

As long as it's running, anyone can exfiltrate your key material from SDRAM. And even for a few minutes after it's running, if they can dump them in LN2 quickly enough. There are kludgy schemes to make this harder, like Schneier's Boojum, but in the end your attacker just needs enough resources and patience. Most FDE schemes don't run crypto ops on the TPM itself - key derivation occurs there, then the results are cached in RAM ( or sometimes, protected CPU registers, in which case they may be able to inject privileged code into the kernel address space? ). LUKS on a colo will probably protect you if you're a fentanyl distributor or movie pirate. Probably not if you're a terrorist or a high-value nation-state target.