Hidoji 🏴

Hide secret messages inside emojis!

Hidoji lets you hide any text message inside an emoji. The emoji looks completely normal, but it secretly contains your hidden message. Only someone with this tool can reveal what's hidden inside.

What does it do?

Hide: Turn "secret message" + 🏴 → 🏴 (looks the same, but contains hidden data!)
Reveal: Turn 🏴 (with hidden data) → "secret message"

The magic happens using invisible Unicode characters that get attached to the emoji. Your message is completely hidden from view but can be extracted later.

Why the black flag 🏴? It's perfect for hiding data because it's simple (no complex parts that might break), widely supported across all platforms, and can hold lots of hidden information due to its Unicode structure.

Quick Start

Step 1: Get Hidoji

go build -o hidoji

Step 2: Hide a message

./hidoji encode "my secret message"

This gives you an emoji that looks normal but contains your hidden message!

Step 3: Reveal the message

./hidoji decode "🏴⁠​‌‌‌​‌​​..."

This extracts your original message from the emoji.

Simple Examples

Hide and reveal a message

# Hide the message "hello world" in a black flag emoji
./hidoji encode "hello world"
🏴⁠​‌​​‌​​​​‌‌​​‌​‌​‌‌​‌‌​​​‌‌​‌‌​​​‌‌​‌‌‌‌​​‌​​​​​​‌‌‌​​‌‌​‌‌​​‌​‌​‌‌​​​‌‌​‌‌‌​​‌​​‌‌​​‌​‌​‌‌‌​‌​​​​‌​​​​​​‌‌‌​​‌‌​‌‌‌​​​​​‌‌​​‌​​⁣

# Get the message back
./hidoji decode "🏴⁠​‌​​‌​​​​‌‌​​‌​‌​‌‌​‌‌​​​‌‌​‌‌​​​‌‌​‌‌‌‌​​‌​​​​​​‌‌‌​​‌‌​‌‌​​‌​‌​‌‌​​​‌‌​‌‌‌​​‌​​‌‌​​‌​‌​‌‌‌​‌​​​​‌​​​​​​‌‌‌​​‌‌​‌‌‌​​​​​‌‌​​‌​​⁣"
hello world

Use different emojis

# Hide message in a pumpkin instead of black flag
./hidoji encode "spooky message" --base "🎃"
🎃⁠​‌‌‌​‌​​​‌‌​​‌​‌​‌‌​‌‌​​​‌‌​‌‌​​​‌‌​‌‌‌‌​​‌​​​​​​‌‌‌​​‌‌​‌‌​​‌​‌​‌‌​​​‌‌​‌‌‌​​‌​​‌‌​​‌​‌​‌‌‌​‌​​​​‌​​​​​​‌‌‌​​‌‌​‌‌‌​​​​​‌‌​​‌​​⁣

Work with files

# Save your secret emoji to a file
./hidoji encode "top secret info" --output secret.txt

# Read it back later
./hidoji decode < secret.txt
top secret info

All Options

Basic Commands

• ./hidoji encode "message" - Hide a message in an emoji
• ./hidoji decode "🏴..." - Get the hidden message back

Useful Flags

• --base "🎃" - Use a different emoji (default is 🏴)
• --output file.txt - Save result to a file
• --copy - Copy result to clipboard (macOS only)
• --quiet - Don't show extra info
• --help - Show all options

Pro Tips

Avoid shell problems with quotes:

# If your message has special characters, use a file:
echo "Hello! How are you?" > message.txt
./hidoji encode < message.txt

Chain commands together:

# Encode and decode in one line
echo "test" | ./hidoji encode | ./hidoji decode

Share secret emojis:

# Copy to clipboard and paste anywhere
./hidoji encode "secret" --copy
# Paste the emoji in chat, email, etc.
# Others can decode it with: pbpaste | ./hidoji decode

Important Notes

• Copy as plain text: Don't use rich text editors - they might remove the invisible characters
• Some apps strip invisible characters: If decoding fails, the app might have cleaned the emoji
• Works best in: Terminal, plain text files, basic text messaging