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> hardcoded set of public keys that include an SGX attestation from those instances. You mean: 1. generate a public/private key in enclave 2. generate attest

> hardcoded set of public keys that include an SGX attestation from those instances. You mean: 1. generate a public/private key in enclave 2. generate attestation from SGX enclave with public key hash. 3. seal the public/private key somewhere so it can be reused later, otherwise pc restart or app failures / no data. 4. publish source code that generates mrenclave somewhere that can be audited. 5. encrypt in place and assume remote trusts you when you say data was only exfiltrated encrypted or not at all. Now, 5 is the problem i mentioned. Why would anyone trust that data was not exfiltrated unencrypted and copied a few times. > and the unencrypted plaintext never leaves the victim organization. You also mentioned this to be fair. Why would this be trusted? 6. Release data if no payment on bitcoin. SGX enclaves do not have magic trusted access to network to get bitcoin payments data. It can be man in the middled or fooled by omission by who controls machibe. So key can be releases by feeding it bad data (payment was not done and time expired - release to the world). There's also the problem that attestation might lead to the originating group if cpu is identifiable.

matthewdgreen 3y ago
Malware encryptors can be left on the system for forensic investigation to discover. You’re correct that there’s no perfect guarantee the ransomware group didn’t also exfiltrate data using another method, but that would be kind of stupid; the idea of this would be to reduce a hard problem (trust a criminal to secure your data and eventually safely delete it) to a simpler problem (trust a criminal group not to do something economically irrational that also requires extra work and stealth at infection time.) You don’t need network access to verify a PoW blockchain transcript is correct, provided the cost of forging that blockchain segment is high enough (plus you can script payment redemption so it requires a signature from the enclave attesting that the information was destroyed.) I’m pretty sure a resourceful ransomware group can source a few motherboards and CPUs that can’t be traced back to them.
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matthewdgreen 3y ago

Malware encryptors can be left on the system for forensic investigation to discover. You’re correct that there’s no perfect guarantee the ransomware group didn’t also exfiltrate data using another method, but that would be kind of stupid; the idea of this would be to reduce a hard problem (trust a criminal to secure your data and eventually safely delete it) to a simpler problem (trust a criminal group not to do something economically irrational that also requires extra work and stealth at infection time.) You don’t need network access to verify a PoW blockchain transcript is correct, provided the cost of forging that blockchain segment is high enough (plus you can script payment redemption so it requires a signature from the enclave attesting that the information was destroyed.) I’m pretty sure a resourceful ransomware group can source a few motherboards and CPUs that can’t be traced back to them.

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