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    SubjectRe: [PATCH v2 0/4] Checkpoint/Restore: Show in proc IDs of objects that can be shared between tasks
    Hello,

    On Fri, Nov 18, 2011 at 05:10:37PM -0500, Kyle Moffett wrote:
    > The #1 rule of one-time pads is never use it for more than one thing,
    > and you use it here for every object in the system.

    The new version is using different poison for different types of
    objects.

    > If you actually want to be able to compare uniqueness without exposing
    > anything vulnerable to various kinds of guessing, you should generate
    > a random 64-bit value for each class of object and then use a proper
    > cryptographic hash function on it:
    > crypto_hash(concat(object_ptr, random_value))
    >
    > Even given the best possible practical attacks against SHA1 or MD5
    > today both still provides more than enough security to prevent someone
    > from guessing "object_ptr" in less than an absurd amount of time.

    So, per-type poison + crypto hash, it is then.

    Thank you very much.

    --
    tejun


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