What is an OTP?
An OTP, or one-time password, is a password or passcode that is valid for one authentication attempt or a short period. It reduces the value of a captured code compared with a reusable password, but it does not by itself prevent phishing or session theft.
English name, abbreviation and common aliases
- English name: One-Time Password
- Abbreviation: OTP
- Common aliases: One-time passcode, single-use password, dynamic verification code
How does an OTP work?
A service or authenticator creates a value from a random challenge, a shared secret, a counter or time. The verifier binds it to the intended account or action, limits attempts, checks expiry and prevents successful codes from being replayed.
A concrete example
A service sends 482193 for a sign-in. The server accepts it once within five minutes and rejects it after successful use or expiry.
OTP vs. related concepts
TOTP is a specific OTP algorithm based on a shared secret and time. SMS verification is a delivery and verification channel, while an OTP Number is a telephone number used to receive one-time codes.
Use cases, benefits and risks
OTPs are used for sign-in, account recovery, transaction confirmation and multi-factor authentication. They limit password reuse, but delivered codes can be intercepted, phished or redirected. Strong systems use short validity, attempt limits, request binding and independent recovery controls.
How does DuoPlus Cloud Number support OTP verification?
For multi-account registration, login and security verification, DuoPlus Cloud Number works alongside DuoPlus Cloud Phone to receive SMS OTP verification codes from supported apps and websites. Users can manage cloud phones and numbers on the same platform, reducing the operational overhead of switching physical SIM cards and tracking codes across separate tools.
Support for number types and regions varies by platform, so actual SMS OTP delivery depends on the destination platform and carrier. DuoPlus Cloud Number is designed for receiving SMS OTPs; codes generated by an authenticator app or hardware key use a different OTP method and do not require a cloud number.
Frequently asked questions
Is every OTP an SMS code?
No. An OTP may be generated by an authenticator or hardware device, or delivered through SMS, email and other channels.
Should an OTP be stored on a cloud phone?
Do not retain or share received codes. If an authenticator app runs on a cloud phone, restrict team access, protect its seed and recovery codes, and keep an independent recovery channel for the account.
