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A comment on AWS Nitro Enclaves: Attack Surface. Parent comment

Re:AWS Nitro Enclaves: Attack Surface by pclmulqdq on Thursday September 26, 2024 @12:40PM (#41660504)
You wouldn't XOR-combine, you would hash them together. Something like:

SHA256(32B from HWRNG-A || 32B from HWRNG-B)

still guarantees you 32 bytes of entropy if either HWRNG-A or HWRNG-B is compromised, and if HWRNG-A and HWRNG-B are both partially compromised you also get 32 bytes of entropy. XOR has weird failure modes (eg if HWRNG-A and HWRNG-B are correlated).

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Re:AWS Nitro Enclaves: Attack Surface by njtransit on Saturday September 28, 2024 @01:08PM (#41681537)
Is that a bit-wise OR? That seems like it would greatly reduce entropy. The probability of any given bit in A | B being 1 is 75%.
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Re:AWS Nitro Enclaves: Attack Surface by ztorkelson on Saturday September 28, 2024 @06:50PM (#41683474)
It’s concatenation.
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