Our AI writing assistant, WriteUp, can assist you in easily writing any text. Click here to experience its capabilities.

A Practical Guide to the Web Cryptography API

View Original View Raw

Summary

This article provides a practical guide to the Web Cryptography API which is a nonstandard interface called Crypto, but was later standardized through a new interface called SubtleCrypto. It explains how to generate symmetric keys, encode data, generate initialization vectors, encrypt data, pack data, unpack data, decrypt data, and decode data. It also provides an example application with code which uses all of these functions to encrypt and decrypt data. Finally, it explains the trade-off of true privacy and how there is no way to recover a user's lost key or encrypted data.

Q&As

What is the Web Cryptography API?
The Web Cryptography API is a standardized interface exposed at window.crypto.subtle that allows for client-side encryption.

What is the recommended symmetric algorithm for encryption?
The recommended symmetric algorithm for encryption is AES-GCM.

How does the use of an Initialization Vector (IV) help with encryption?
The use of an Initialization Vector (IV) helps with encryption by introducing true randomness into the encryption strategy. This ensures that repeating character sequences in the input data produce varying byte sequences in the resulting cipher.

How can data encrypted with the Web Cryptography API be stored and transmitted?
Data encrypted with the Web Cryptography API can be stored and transmitted by converting the binary data buffers into base64-encoded strings.

What are the tradeoffs of implementing client-side encryption?
The tradeoffs of implementing client-side encryption include the inability to recover lost keys or encrypted data if the key is lost, as the keys are never transmitted to the server and the data is never transmitted in plain text.

AI Comments

👍 Great summary! I'd love to hear about example use cases for client side crypto, if anyone in the community has them!

👎 There is no way to recover lost keys, because the keys are never transmitted to the server. This also means users cannot recover the encrypted data if they lose said key, because the data is never transmitted in plain text to the server.

AI Discussion

Me: It's an article on practical guide to the Web Cryptography API. It goes into detail on how to generate keys, encode and encrypt data, transmit and store data, and decrypt data.

Friend: Interesting. What are the implications of this article?

Me: Well, it has implications for data privacy and security. By utilizing the Web Cryptography API, developers can ensure that data is kept secure both on the client-side and on any remote server. It also gives users the choice to opt-in if they don't trust a server to store their plain text data.

Action items

Research and implement a client-side encryption strategy for your own application.
Experiment with different encryption algorithms to determine which is best suited for your use case.
Consider the implications of lost keys and forgotten passwords when implementing client-side encryption.

Technical terms

SubtleCrypto: The Web Cryptography API was initially exposed through a nonstandard interface called Crypto, but it was later standardized through a new interface called SubtleCrypto. This article will focus on the public SubtleCrypto interface exposed at window.crypto.subtle.
Encryption: The process of encoding data so that it is unreadable by anyone except those with the key to decode it.
Symmetric Algorithm: An encryption algorithm that uses the same key to both encrypt and decrypt data.
AES-GCM: The recommended symmetric algorithm for the Web Cryptography API. It stands for Advanced Encryption Standard in Galois/Counter Mode.
Initialization Vector (IV): A random value used to introduce true randomness into an encryption strategy.
Base64-encoded Strings: A way of encoding binary data into a string format that is portable and can be transmitted or stored.
TextEncoder/TextDecoder: Utility classes used to encode and decode data into a byte stream.
CryptoKey: An object used to store cryptographic keys.