Re: [EME] specification question: about 8.1 Use Cases

On Jun 30, 2012, at 1:00 AM, Sunyang (Eric) wrote:

There is a sentence in this part, which indicate “user is not an adversary”.
I am not sure what is the meaning of this in this specification?

It's security terminology: http://en.wikipedia.org/wiki/Adversary_(cryptography)

When considering content protection, the user is an "adversary" in this sense because we are trying to make it difficult for the user to obtain certain information (keys, decrypted content etc.) that they are not entitled to under the terms of the service they are using.

So the sentence you mention refers to use-cases where this is not the case. For example, use-cases where the encrypted content belongs to the user themselves, and the purpose of the encryption is to keep that content confidential from entities other than the user.

…Mark


Can anyone help me to understand it?
Thanks


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