Comparison

Secret KB vs Underlayer

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Secret KB

Features
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Send a normal text to your friend or anyone you want with a private and secret message! With Secret Text Keyboard, you can send secret messages to your friends on iMessage, Messenger, WhatsApp, Skype, Line, Wechat, Gmail, etc. While it seems to be no difference from other texts, a text sent by Secret Text Keyboard contains a secret message that can only be seen by you and the one you send it to. No private message will reveal itself until it is decoded by the recipient, which means your secret will be absolutely safe! Download Secret Text Keyboard now and feel free to convey your secrets! Here is how Secret Text Keyboard works as to: -Send A Secret 1. Install Secret Text Keyboard and allow full access. 2. Switch to Secret Text Keyboard and enter your secret message. 3. Tap the Encode button to make it seem like a normal text. 4. Tap send as usual. -Decode A Secret 1. Install Secret Text Keyboard and allow full access. 2. Copy the secret message you've received from your friend. 3. Tap the Decode button to decode that secret. About Allowing Full Access: Allowing full access does not grant us access to other keyboards that you have, except this Secret Text keyboard. Full access is necessary for encoding and decoding secret messages. We do not read, record or transmit anything you type. Secret Text Keyboard will be used strictly for entertainment purposes only.

About

Underlayer

Features
Read full description

UNDERLAYER - STEGANOGRAPHY MADE SIMPLE Transform ordinary images into secret carriers. Hide confidential messages invisibly within photos and share them through any messenger without raising suspicion. KEY FEATURES: HIDE SECRETS • Embed text messages invisibly into any image • Two encoding modes: Hidden (invisible pixels) and Open (colored frame) • Open mode survives messenger compression (Telegram, WhatsApp, etc.) • Share processed images directly or save to gallery REVEAL MESSAGES • Extract hidden text from steganographic images • Automatic detection of encoding method • Works with images received through messengers • Share intent support - open images directly from gallery WHY UNDERLAYER? • Simple & Intuitive - No cryptography knowledge required • Messenger-Friendly - Open mode designed for compressed sharing • Privacy First - All processing happens locally on your device • Universal - Works with JPG, PNG, WebP formats • No Account Required - Start using immediately USE CASES • Private communication through public channels • Watermarking images with hidden ownership data • Secure note-taking in plain sight • Educational tool for learning steganography • Fun way to send secret messages to friends SECURITY & PRIVACY • No internet connection required for processing • Your messages never leave your device • No data collection or tracking • Complete control over your secrets PREMIUM FEATURES • No banner ads at the bottom • No interstitial ad interruptions • Process unlimited images without ad breaks HOW IT WORKS 1. Select any image from your gallery 2. Enter your secret message 3. Choose encoding mode (Hidden or Open) 4. App embeds message into image pixels 5. Share through messengers or save locally 6. Recipient opens image in Underlayer to reveal message ENCODING MODES EXPLAINED HIDDEN MODE • Message embedded invisibly in image pixels • Completely undetectable to human eye • Best for uncompressed image sharing • Lost when image is compressed by messengers OPEN MODE • Message encoded as colored frame border • Visible as decorative edge around image • Survives Telegram, WhatsApp compression • Recommended for messenger sharing INTERNATIONAL • Available in English and Russian • More languages coming soon • Automatic language detection Whether you're a privacy enthusiast, security professional, or just curious about steganography - Underlayer makes it accessible to everyone. Download now and start hiding your secrets in plain sight! Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

Secret KB4 screens
Underlayer4 screens

Verdict

The call

The clearest difference is price: Underlayer at Free against Secret KB's $0.99. Secret KB's advantage is in-app purchases (none vs 1) and ads (none vs shown). On device support and iOS requirement there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Underlayer is free to download; Secret KB costs $0.99 up front. Underlayer sells 1 in-app purchase, starting at $2.99 per 7 days. Secret KB asks for nothing beyond the download.

UpkeepUpdate frequency

Secret KB ships an update every 10 days, Underlayer every 5 months. The most recent releases landed on September 14, 2026 and September 12, 2026 respectively.

Scorecard4 real differences · 2 level
Secret KB versus Underlayer: the parameters behind the verdict, then further details
ParameterSecret KBUnderlayer
Price$0.99Free — better
Update frequencyEvery 10 days — betterEvery 5 months
AdsNo — betterYes
In-app purchasesNo — betterYes
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS14.0 — better15.1
Further details — not scored
Size6 MB169 MB
Age rating4+4+
DeveloperAsadullah JamadarMihail Rukavishnikov

In-app purchases

None

Secret KB

No in-app purchases

1 purchases

Underlayer

Subscriptions1
  • Premium$2.997 Days

Questions

Is Secret KB free?
Secret KB costs $0.99, with no in-app purchases.
Is Underlayer free?
Underlayer is free to download, with in-app purchases available.
Do Secret KB or Underlayer have ads?
Underlayer shows ads; Secret KB does not.
Which is updated more often, Secret KB or Underlayer?
Secret KB ships an update every 10 days, and Underlayer every 5 months. Most recently, Secret KB was updated on September 14, 2026 and Underlayer on September 12, 2026.

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