I am currently working on a secure messaging website and I had been using RSA 2048 for encryption, decryption and signing of messages but I found it to be EXTREMELY LAGGY so i've moved to 1024.
I did a timing test and these are my results (this was a test of generating a private key from the same string in cryptico.js):
2048 | 6403ms (6 seconds)
1024 | 515ms (0.5 seconds)
896 | 89ms (0.08 seconds)
I would like to know if if 896 or 1024 are un-secure for use with messaging and what the best key size would be?