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Is that actually true? My understanding of how E2E encrypted iMessage works is that in group chats it does indeed send 30 copies of your messages, individual e

Is that actually true? My understanding of how E2E encrypted iMessage works is that in group chats it does indeed send 30 copies of your messages, individual encrypted for each recipient in the group. https://support.apple.com/en-gb/guide/security/sec70e68c949/web https://support.apple.com/en-gb/guide/security/sec70e68c949/... > For group conversations, this process is repeated for each recipient and their devices.

judge2020 4y ago
Perhaps they're doing multi-recipient encryption, ie. the data is wrapped with one key, and that private key is then encrypted with the public key of each recipient, so everyone ends up using the same private key to decrypt the file data itself. This means the actual file data isn't sent 20+ times (although the data is indeed stored in everyone's Messages backups separately; if Apple is doing de-dupe based on file data+filename, they're probably benefiting from deduping group message images).
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lxgr 4y ago
> APNs can only relay messages up to 4 or 16KB in size, depending on the iOS or iPadOS version. If the message text is too long or if an attachment such as a photo is included, the attachment is encrypted using AES in CTR mode with a randomly generated 256-bit key and uploaded to iCloud. Only the attachment encryption key and URL need to be encrypted to each recipient.