I Hid a Watermark in Screenshots, and iOS Thought It Was a Password

About this episode

The episode discusses a method of embedding a watermark in screenshots using iOS's secure text entry feature and the unintended consequences it caused.

This story was originally published on HackerNoon at: https://hackernoon.com/i-hid-a-watermark-in-screenshots-and-ios-thought-it-was-a-password . Exploiting iOS's secure text entry to build a watermark that only appears in screenshots, and the password-autofill bug it caused. Check more stories related to programming at: https://hackernoon.com/c/programming . You can also check exclusive content about #ios-development , #ios-screenshot-watermark , #viral-growth-mechanics , #product-led-growth-tactics , #uikit-rendering-behavior , #mobile-app-attribution , #ios-development-hacks , #hackernoon-top-story , and more. This story was written by: @grievouz . Learn more about this writer by checking @grievouz's about page, and for more stories, please visit hackernoon.com . Screenshots were the app's biggest sign-up channel, so I built a watermark that's invisible in the app but appears when users take a screenshot, using iOS's secure text entry flag, which strips content from screenshots to protect passwords. It worked. It also made iOS think every chat message was a password field, breaking autocorrect and triggering "Save to Keychain" prompts. Fix: drop the UITextField entirely and…

Topics covered

• iOS development
• watermarking
• secure text entry
• mobile app development
• programming

Keywords

• watermark
• iOS
• screenshot
• secure text entry
• autocorrect
• Keychain
• CALayer
• programming

Mentioned in this episode

Organizations: HackerNoon

Products: iOS

Books & works: I Hid a Watermark in Screenshots, and iOS Thought It Was a Password

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