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CompTIA Security+ 4.6 NIST 800-53 IA-5 NIST 800-53 IA-2
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Will This Code Work?

Accepted, rejected as already used, or rejected as expired? Decide what happens to each try with a one-time code.

⚑ Complete this interactive to capture a CTF flag worth 5 points.

About this interactive

A one-time password (OTP) is a code that proves you hold a device, usually a phone, as one step of a sign-in. The One-Time Passwords lesson gives it two limits. It works once. After a code has been used to sign in, it is no longer valid, so typing it again, or someone else replaying it, fails. It expires. A code sent by text, call or email, and the time-based code an authenticator app shows, is good for a short time, perhaps thirty seconds, a minute or fifteen minutes. After that it fails even if nobody used it, and a new code has to be requested or generated. The exception is the counter-based kind (HOTP) in the next lesson: its codes do not run out on a clock. The code reaches you in one of two ways: it is sent to the device, by text message, voice call or email, or it is generated on the device, by an authenticator app. You may also hear it called a one-time PIN, a passcode or a dynamic password. A quick test for each card: has this code been used already? If not, is it still inside its time limit?

What you'll learn

Aligned to

CompTIA Security+
4.6 Given a scenario, implement and maintain identity and access management.
NIST 800-53
IA-5 Authenticator Management
IA-2 Identification and Authentication (Organizational Users)

Key terms

One-time Password
OTP
A One-time Password is a code valid for only a single authentication session or transaction, generated by hardware tokens, authenticator apps, or SMS, providing stronger security than static passwords by eliminating the risk of credential replay attacks.
Multi-Factor Authentication
MFA
An authentication method that requires users to provide two or more verification factors to gain access.
Soft Token
A software-based authentication token, such as a code delivered to a mobile device or generated by an authenticator app.

Topics

Authentication One Time Password Interactive Categorize

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