Node.js和Webcrypto之间的RSA加密

Question

I'm really stuck on this! What i'm trying to do:

• Generate a RSA keypair using ursa/webcrypto
• Send the public key as PEM over the wire
• Import the public key on the other end, and encrypt some text with it
• Send back the ciphertext and decrypt it on the other end using the private key

Now somehow I get either an undefined DOMException in the browser if I try to do the encryption part with ursa, or I get this error in Node.js when I do the encryption in the browser:

Missing error handler on `socket`.
Error: error:040A1079:rsa routines:RSA_padding_check_PKCS1_OAEP_mgf1:oaep decoding error
    at Error (native)
    at Object.decrypt (/home/jeroen/projects/crypto-nodebrowser/node_modules/ursa/lib/ursa.js:358:33)
    at Socket.<anonymous> (/home/jeroen/projects/crypto-nodebrowser/server.js:34:50)
    at emitOne (events.js:77:13)
    at Socket.emit (events.js:169:7)
    at Socket.onevent (/home/jeroen/projects/crypto-nodebrowser/node_modules/socket.io/lib/socket.js:330:8)
    at Socket.onpacket (/home/jeroen/projects/crypto-nodebrowser/node_modules/socket.io/lib/socket.js:290:12)
    at Client.ondecoded (/home/jeroen/projects/crypto-nodebrowser/node_modules/socket.io/lib/client.js:193:14)
    at Decoder.Emitter.emit (/home/jeroen/projects/crypto-nodebrowser/node_modules/component-emitter/index.js:134:20)
    at Decoder.add (/home/jeroen/projects/crypto-nodebrowser/node_modules/socket.io-parser/index.js:247:12)

I made a minimal code example at https://github.com/jvanveen/crypto-nodebrowser that shows the issue. Any help on this is welcome!

Answer 1

Are you able to tell us both the code you are running and the browser it is running in?

Some browsers may only do RSA-OAEP with SHA-1 but from the brief description you have given it is having issues with the decryption. I think more details are needed.

Answer 2

Ok, I finally got it. Openssl has OAEP padding hardcoded using SHA1, so ursa's openssl bindings are not suitable if you want to use RSA-OAEP-256. I couldn't find a way to make this work with node-rsa, but Node-forge is quite straightforward here. Just use something like:

 var encrypted = publicKey.encrypt(bytes, 'RSA-OAEP', { md: forge.md.sha256.create() });