OTP

Why it matters

Typically four to seven digits. The code proves you can receive messages at that number at that moment — nothing more. It is not identity verification, which is why SMS OTP is considered a weak second factor by security professionals and a strong one by product managers.

Related terms

• A2P messagingA2P (application-to-person) SMS is automated messaging from a system to a person, different from person-to-person texts.
• SIM swapA SIM-swap attack is when someone persuades a mobile carrier to port a victim's number onto a SIM the attacker controls.

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