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What Is Leetspeak (1337)? A Brief History

The origins of 1337, common letter swaps, and why it’s weak for passwords.

Where leetspeak came from

Leetspeak — “leet” from “elite” — emerged in early internet bulletin boards and gaming communities in the 1980s–90s. Users replaced letters with similar-looking numbers and symbols, partly as an in-group code and partly to dodge basic word filters.

Common substitutions

Typical swaps include A→4, E→3, I→1, O→0, S→5, T→7 and B→8, so “leet” becomes “1337” and “hacker” becomes “h4ck3r”. The style ranges from light (a few swaps) to heavy (symbols and creative letter combinations).

Don’t use it for passwords

Swapping letters for look-alike numbers (“P4ssw0rd”) feels clever but offers almost no real security — password-cracking tools try these substitutions automatically. Use a long, random passphrase instead. Leetspeak is best kept for fun usernames and retro flair.

FAQ

Is “P4ssw0rd” a strong password?+

No. Simple letter-to-number swaps are predictable and easily cracked. Choose a long, unique passphrase or use a password manager.