Is there a BIP38 equivalent for Ethereum private keys?

Question

What is the best practice to encrypt an Ethereum private key? For example, Bitcoin has BIP38.

Answer 1

The best practice is to comply with the Web3 Secret Storage Definition. This will allow your private key to be easily imported into clients such as Geth and cpp-ethereum (eth). The definition encodes to a JSON file (unlike a Base58Check-encoded printable string as in BIP38) and includes test vectors.