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    I am confused how the presented scheme is anything close to tracing. The first step is

    The plaintext that is to be traced is submitted along with RF, NF and context.

    But NF is a 256bit random nonce that no one other than the sender and recipient have access to. You may be able to guess a plaintext, but there’s no way you can guess that.

    Additionally, it seems to me that if you have access to an oracle that can say if a given ciphertext is equal to some plaintext, you have broken ciphertext indistinguishability, a property that is very important to confidentiality (“Indistinguishability is an important property for maintaining the confidentiality of encrypted communications.”)

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      There would be a step where the reveal of this nonce would be compelled, similarly to how message franking implements such a step in its current form. The idea is that you can just substitute the rationale for this step from “abuse reporting” to “message tracing”.

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        How is compelling the reveal of the nonce any different from compelling the reveal of the plaintext? They’re stored next to each other and the only parties that have the nonce are the same parties that have the plaintext. The difference between “abuse reporting” and “message tracing” is which party is performing the action, and that makes all the difference.

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          As far as I understand, the nonce serves to validate the initial HMAC, which serves as a pre-commitment to the authenticity of the message within its original context.