Flowcharts & Processes

Two-Factor Authentication Verification Flow

Flowcharts & Algorithms diagram · made in Skemio

Flowchart showing 2FA verification: checking credentials, verifying rate limits, validating TOTP codes, checking backup codes, and session grant.
Flowchart showing 2FA verification: checking credentials, verifying rate limits, validating TOTP codes, checking backup codes, and session grant.
Open it in SkemioMake your own

What it shows

  • Verifies primary password and enforces brute-force rate limits.
  • Validates TOTP HMAC codes against server time windows (+/- 1 step).
  • Offers single-use backup recovery codes when TOTP generators are lost.

The takeaway

Robust 2FA requires strict rate limiting, time drift windows, and single-use backup recovery codes.

More flowcharts & algorithms diagrams