Search and Rescue Numerical Encryption Grid (SARNEG)

SARNEG is a lightweight encryption method designed for securely transmitting numerical information, such as map grid coordinates, over non-secure communication channels. It is ideal for Search and Rescue (SAR) scenarios, where isolated individuals must communicate their location discreetly. (Chesbro, 2018)

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⚠️ Security Note

SARNEG is not a strong encryption method. It is suitable for:

• Obscuring location in hostile environments.
• Short-term secrecy of numerical data.
• Human memorization and quick encoding.

It is not recommended for encrypting sensitive or high-volume data.

🔐 How It Works

SARNEG substitutes each digit from 0–9 with a corresponding letter from a 10-letter keyword (with no repeating letters).

Step-by-Step:

1. Choose a 10-letter keyword (no repeated letters)
   Examples: AFTERSHOCK, BLACKHORSE, CORNFLAKES, COMBATHELP

2. Create the mapping:

   Digits:   0 1 2 3 4 5 6 7 8 9
   Keyword:  A F T E R S H H O C K
   

3. Encrypt the numeric portion of your message using this mapping.

🔄 Example

Input Grid Coordinate (MGRS):

45V UC 76232 63380

Using keyword AFTERSHOCK:

76232 63380 → OHTET HEECA

Encrypted Message:

SARNEG: OHTET HEECA

Note: Prefix (45V UC) is typically not transmitted unless necessary. The application is still however capable of handling these inputs.

References

Chesbro, M., 2018. Operating in Hostile and Non-Permissive Environments: A Survival and Resource Guide For Those Who Go in Harm's Way. pp.172–173.

Authors

• @LiamTownsley2