Fundamentals BroadNet answer

What is 2FA (two-factor authentication)?

Last reviewed July 22, 20261 min readReviewed by BroadNet engineering

Quick answer

Two-factor authentication (2FA) requires a user to prove their identity with two independent factors before access is granted — typically something they know (a password) and something they have (a phone receiving an OTP). SMS OTP is the most widely deployed second factor in the world. 2FA sharply reduces account-takeover risk, because a stolen password alone is no longer enough to log in.

Plain-language definitionVendor-neutralReviewed July 22, 2026

DiagramThe OTP journey, with channel fallback

User requests a codeSign-in, payment or sign-up
Your app calls the verify APIOne request per code
BroadNet delivers the codeOn the best available channelFallback if undeliveredSMSWhatsAppVoice
User enters the codeChecked against the issued code
VerifiedAccess granted

The long answer

Everything worth knowing, nothing that isn't.

§01

The factor categories

Authentication factors fall into three groups: something you know (password, PIN), something you have (phone, hardware token, passkey), and something you are (fingerprint, face). 2FA combines exactly two of these; MFA (multi-factor) combines two or more. SMS OTP pairs a password with possession of the phone. See /answers/what-is-otp.

§02

Delivery channels and their trade-offs

SMS OTP has the widest reach but is exposed to SIM-swap and AIT abuse; authenticator-app TOTP is phishing-resistant but needs setup; WhatsApp, voice, and Flash Call OTP add reach and cost options; passkeys remove the shared secret entirely. Robust systems fail over across channels in one call. See /answers/what-is-flash-call-verification and /products/myotp.

BNWritten by the BroadNet engineering team·Operating carrier-grade messaging since 2003, headquartered in Dubai·Editorial standards

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