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How random are TOTP codes?


I'm pretty sure that the 2FA codes generated by my bank's TOTP app have a bias towards the number 8 - because eight is an auspicious number. But is that just my stupid meaty brain noticing patterns where none exist? The TOTP algorithm uses HMAC, which in turn uses SHA-1.

Is it possible that a TOTP code could be formed which shows a clear bias to a specific number? I love being able to check the source code - but sometimes it's just as reassuring to measure the output. Twitter Facebook LinkedIn Reddit HackerNews Lobsters Pocket WhatsApp Telegram

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TOTP codes