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Discussion on: System Design: WhatsApp

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fk profile image
Fırat Küçük

Good article, tables should not contain messages. Whatsapp uses end to end encryption. Communications are handled without an intermediate server.

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lweiner profile image
Lukas Weiner

They are handled and stored in a database, but they are encrypted and decrypted on your phone. So that's why you can't load all message from the server as soon as you are changing your device. If you want to go deeper into the topic you can search for asymmetric cryptography. So yes the author is right with storing the message on the server, the only difference is that they are not stored as plain text, they are stored encrypted.

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fk profile image
Fırat Küçük • Edited

techuntold.com/where-whatsapp-mess...

The only time a message is stored on WhatsApp’s servers is if the recipient cannot receive it (maybe they’re offline or don’t have a WhatsApp account). In cases like those, the message(s) you sent are automatically deleted off of WhatsApp’s server in 30 days’ time.

So this probably has you wondering if WhatsApp doesn’t store your messages on its servers, then where are they stored? The answer is, your WhatsApp messages are stored locally on your phone in the form of encrypted backups.

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lweiner profile image
Lukas Weiner

Ah I didn't knew that, thanks for correcting me. Really interesting.