MyEtherWallet: keystore files, lost passwords, old wallets

Never upload your keystore JSON to a website that promises to “decrypt” it. Real recovery runs offline on hardware you (or we) control. Your file leaves our possession the day we’re done.

What MEW actually gave you

When you created the wallet, MEW handed you a UTC/JSON keystore file plus a password. The file is a scrypt- or PBKDF2-encrypted envelope around your private key. With the password, decryption is instant. Without it, the path is targeted brute-force using what you remember.

What makes a case recoverable

• You remember the rough length, character set, or theme of the password.
• You used a password manager and have older entries to seed the search.
• You have any related passwords from the same era — people reuse patterns.
• The file is intact (not partially copied or truncated).

What kills a case

• A truly random 16+ character password with no memory at all — computationally infeasible.
• A corrupted keystore where the cipher block is partly missing.
• Funds already swept by a previous compromise (we’ll check the address first).

The mnemonic case

Later MEW versions also issued a 12- or 24-word seed. If you have that, you don’t need the keystore at all — restore into MetaMask, MEW, or any BIP39 wallet and verify on Etherscan.