Comments (1)
If Alice is sending some encrypted message to Bob
- Alice gets Bob's public key,
gx
- Alice first generates an ephemeral keypair (random 32 bytes),
y
(private) andgy
(public) - Alice uses Elliptic-curve Diffie–Hellman (ECDH) to derive a shared secret from her y and Bob's gx,
px = ECDH(y, gx)
(32 bytes) - Alice uses SHA512 as KDF.
ke || ka = SHA512(px)
to getke
as encryption key (32 bytes) andka
as authentication key (32 bytes) - Alice encrypts her message
m
using AES256 in CBC mode with randomiv
.c = AES256-CBC(ke, iv, m)
- Alice computes MAC,
mac = HMAC-SHA256(ka, iv || gy || c)
- Alice sends
iv || gy || mac || c
to Bob.
Once Bob gets gy
he also uses ECDH
px = ECDH(x, gy)
Then he decrypts the message, checks MAC, etc etc
There's no single standard ECIES and you can change it up a bit in your implementation if you wish, for example you can use ke = HMAC-SHA256(px, 0x01)
and ka = HMAC-SHA256(px, 0x02)
as KDF. (I probably should have done this but if I change the lib at this point it'll break previously encrypted messages)
Also you can potentially replace AES256-CBC with AES256-GCM, in which case you don't even need to derive authentication key or compute MAC yourself.
from eth-ecies.
Related Issues (5)
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from eth-ecies.