Never use a .env file again!

A better and safer way to store your private keys is in foundry.

Run this on your terminal (not code editor, it may have bugs!)

cast wallet import myKey --interactive        

The key name can be whatever you want it to be (replace myKey as desired).

The interactive flag will interactively as you for the private key and your password as shown:

Enter private key:        

Enter password:         

Once complete, you will get such a response:

myKey keystore was saved successfully. Address: 0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266        

All you now need to remember is your password ( use something unique, not your regular password used in other places since you a leakage in one site can cost you this too).

When you run

cast wallet list         

on the terminal, you will get a list of all your keys, in my case it will only be one

myKey (Local)        

To use the private key to deploy, follow this:

forge script script/DeployMyContract.s.sol:DeployMyContract --rpc-url https://localhost:8545 --account myKey --sender 0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266 --broadcast         

You will then be asked for the keystore password for it to access the stored key.

To see all your keys run these one by one:

cd        

cd .foundry/keystores        

ls        

It will return your keys as earlier stored.

myKey        

To see the content of the key:

cat myKey        

And you'll get this encrypted version of your private key that follows the ERC-2335: BLS12-381 Keystore format:

{"crypto":{"cipher":"aes-128-ctr","cipherparams":{"iv":"5f9b4bfb170595389fb949f2f49bb612"},"ciphertext":"de6a21cc9602227817d8c7288c3e3ed7226ff058f7ac6181abf5411577ea4ed6","kdf":"scrypt","kdfparams":{"dklen":32,"n":8192,"p":1,"r":8,"salt":"0138eac2292ea1a746de88439101057e787c9b2a6cf5bf4f5af933661ded08d0"},"mac":"993e7aadde4ea1ff9b489fe548082878322585296c8cada4a75db8fe4128aaa0"},"id":"cbdcfe6c-2ac4-4c46-a9f3-58e1b1758f75","version":3}        

When you run history, you will get all the recent commands including your unencrypted private key. Anyone with access to your terminal can steal your private key even after you have encrypted it.

on the terminal run:

history -c        

This will clear all history.

Remember to also clear the bash history:

cd        

rm .bash_history        

You are now safer than 95% of developers around the world!

It's fun isn't it? Let's thank @rplusq for this awesome security improvement.