Post #4150587

@greyarea@mitra.vpclmulqdq.moe I can think of two scenarios where HPKE-level sender authentication or aad binding might be important: 1. The sender creates an activity that is attributed to somebody else, encrypts it, and sends to the recipient. This shouldn't be a problem, because the inner activity MUST be portable, and therefore required to have an integrity proof. A compliant recipient can't be fooled into thinking that misattributed activity is real. 2. Somebody (e.g. server operator) takes the fep0806:cipherText out of EncryptedActivity, and creates a new activity with the same fep0806:cipherText but different id, actor and/or to. This shouldn't be a problem either. In the worst case, the activity will be delivered to somebody else who will not be able to decrypt it. Replacing id and actor may be even a good thing (obfuscation). it was a giant mess of w3c specs. It's an ever-expanding mess of W3C specs, RFCs and FEPs. Integrity proofs are relatively new, they are described in Data Integrity W3C spec: https://www.w3.org/TR/vc-data-integrity/