blog/a-practical-guide-to-the-web-cryptography-api

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blog/a-practical-guide-to-the-web-cryptography-api

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https://voracious.dev/blog/a-practical-guide-to-the-web-cryptography-api

[dev4ever888]

hi :) thank you for this article. its very difficult to find a ressource about web crypto on the web.

i send you a message because i have a problem for decrypt.

I have no problem encrypting the message and storing it in my mongodb database.

when I retrieve this information and add it to the decrypt function, I get the

Uncaught (in promise) Error

Do you have an idea ?

[davidmyersdev]

Hi @dev4ever888. 👋 It's hard to say what the issue is without seeing your project. Does the decrypt function work before you send and persist it to MongoDB? If so, then it sounds like there could be an issue with the transmission or storage of your cipher, iv, or keys. All of those should be packed and unpacked on the client. If the decrypt function does not work before you send it, then it sounds like maybe something is not working in your implementation. I'd be happy to take a look if you want to share a reproducible example!

[dev4ever888]

Hello :)

yes I should have put an example.
Yes if I take your code, everything works correctly but does not allow a decryption later :)

Finally I managed to solve the problem.

In fact I didn't understand the basic operation and I only store the "cipher" and the "iv" in my mongodb database.

I realised that in order to decrypt the message later on, the key must also be stored.

In order to store the key you have to use the "exportKey" function first and then "pack" the result.

In your example we can decrypt the message because the key variable is still available :)

I'll try to put the code as an example.

code for explain

https://pastebin.com/89f13VUC

In any case a big thank you for your tutorial, I wanted to find a solution in native and it's done, it avoids having to always add packages :)

[davidmyersdev]

Ah, that definitely makes sense! Thanks for following up here. 😄

[dev4ever888]

no worries :) thanks again for the article ^^