SynCrypt

Polymorphic encryption & obfuscation for red/blue team research

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✨ Features

• Polymorphic Output: Each encryption is unique using random seeds & encoding.
• Junk Masking: Random characters obfuscate the ciphertext to evade simple detection.
• Multiple Encodings: Supports 5 unpredictable formats (synxxxx, sxxyxxn, etc.).
• Compact Header: Only 48 bytes (32-byte seed + 16-byte nonce).
• 256-bit Symmetric Key for encryption/decryption.
• CLI Interface: Easy to encrypt/decrypt messages.
• File Output: Results saved to enc.log for convenience.

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⚙ How It Works

1. Random seed + nonce generated per encryption.
2. Plaintext encrypted using a custom S-box + encoding map.
3. Junk characters inserted after every 2 real characters.
4. Decryption reverses the masking & restores original text.

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🚀 Quick Start

# Build
gcc -o syncrypt.exe encrypt.c syncrypt.c

# Run
./syncrypt.exe

Example: Encrypting EICAR Test String

Header (paste for decryption):

b3Z12n4dIc8m43kbbk8baa6s1fv03w5as7dr09e38n25Z1fK5dyd4CcbxfcF96xf5T45L3bS13g0dy89p0aS1cFdbaaed32p20o9ao50eeeF40x78Z36Bfdc12O49e32Jf6U9ev7dP49vdca

Encrypted:

sybn0o19y4sGynp00o14esyyn0L07f4sPynB02N26Psyln0j17V2sRynV00i68psyYn0a10m7syyne00h90wsyQn0n05q5srynq00P35Msyxn0U02j1s...

(truncated for readability)

Decrypted Result:

X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*

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🎯 Use Cases

• Red Team: Payload staging, C2 obfuscation, loader beacons, bypass naive DLP/IDS.
• Blue Team: Detection research, reverse engineering, forensic analysis.
• Research: Demonstrates limits of pattern-based & entropy detection.

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🔍 Detection Notes

• Junk-masked + polymorphic output evades simple regex/YARA detection.
• Header + key are required to decode; decryption impossible without them.
• Forensics: repeated 2 real + 1 junk character patterns can be tracked.

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📌 Future Goals

• Support binary/file encryption.
• Integrate with C2 frameworks (Cobalt Strike, Mythic, Merlin).
• Add adaptive junk patterns for better evasion.
• Provide Python/PowerShell wrappers.
• GUI or web-based frontend.
• Streaming encryption for large files.
• Peer review & detection/cryptanalysis testing.

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⚖ License & Disclaimer

MIT License. For research, red/blue team development only. Not intended for sensitive production data.

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SynCrypt – polymorphic encryption made simple & flexible for research purposes.