🔐 Every app has a login. But do you know what's happening under the hood?

Here are the most common login mechanisms every developer (and tech enthusiast) should know:

𝗣𝗮𝘀𝘀𝘄𝗼𝗿𝗱-𝗕𝗮𝘀𝗲𝗱 𝗔𝘂𝘁𝗵𝗲𝗻𝘁𝗶𝗰𝗮𝘁𝗶𝗼𝗻

The most traditional method — user provides a username/email and a secret password.

• Plain passwords (basic, least secure)

• Hashed + salted passwords (bcrypt, Argon2, PBKDF2)

• Password managers auto-fill strong, unique passwords

𝗠𝘂𝗹𝘁𝗶-𝗙𝗮𝗰𝘁𝗼𝗿 𝗔𝘂𝘁𝗵𝗲𝗻𝘁𝗶𝗰𝗮𝘁𝗶𝗼𝗻 (𝗠𝗙𝗔 / 𝟮𝗙𝗔)

Combines two or more factors for stronger security:

• Something you know — password, PIN

• Something you have — OTP via SMS, authenticator app (TOTP/HOTP), hardware key

• Something you are — biometrics

𝗢𝗧𝗣 (𝗢𝗻𝗲-𝗧𝗶𝗺𝗲 𝗣𝗮𝘀𝘀𝘄𝗼𝗿𝗱)

A temporary, single-use code:

• SMS OTP — code sent via text message

• Email OTP — code sent to email

• TOTP — Time-based (Google Authenticator, Authy)

• HOTP — Counter-based OTPs

𝗣𝗮𝘀𝘀𝘄𝗼𝗿𝗱𝗹𝗲𝘀𝘀…