When modern communication methods fail, Morse code is still a robust fallback option. However it does not provide confidentiality. The purpose of this repository is to provide some tools for transmitting and receiving sensitive informations. It can be adapted to any radio equipment.

To communicate securely, you need to generate and share cryptographic secrets :

journey
    title states and phases
    section Pre-Operational Phase
      Generation: 2: Alice
      Distribution: 3: Alice, Bob
    section Operational Phase
      Communication: 6: Alice, Bob
    section Post Operational Phase
      Destruction: 3: Alice,Bob
    section Destroyed phase
      Destroyed: 2: Alice,Bob

This POC simplify the NIST.SP.800-57 Key States :

Keep in mind the Key Management Phases and Functions :

flowchart TD
    P[Pre-Activation]
    A[Active]
    D[Destroyed]
    C[Compromised]

    P --> | Generation | P
    P --> | If not used | D
    P --> | Integrity or Confidentiality suspicion | C
    P --> | Distribution| A
    A --> | After Used | D
    A --> | Integrity or Confidentiality suspicion | C
    C --> | Not allowed or needed | D

This example generates the AES256 key and the IV (initialization vectors) for your future messages.

python ./MsgToCypher.py test

# key: 9CEA372979FFDCBA028BD523A3F43A44B527DE31E2BBAE56F641D87D3F6C80BC
# iv: A977EA111934D65E8A6B5AC3D52B82F8
# cipherText: EFAADCF7EA0A786EF7B4EF7504605970
# next iv : 1DAA7C45D2D1D68B934BC3E71F2D6CAC
# next iv : 6DEBDB4819F6639AC7288EE2DBE7C901
# next iv : F9A5240967B6C3AD88CB7E9A04434822
# next iv : F2427CAF0E5EF2F65B9A2AA4D8E43F79

Obfuscation is not security, but to mitigate the risk of interception you can change frequency over time.

gantt
    title Frequencies Plan 
    dateFormat  YYYY-MM-DD
    section Fréquences
    f1 :active, T1, 2025-04-10, 2025-04-20
    f2 :active, T2, 2025-04-01, 2025-04-05
    f3 :active, T3, 2025-04-20, 2025-04-25
    f4 :active, T4, 2025-04-05, 2025-04-10
    f5 :active, T5, 2025-04-25, 2025-05-01
    f6 :active, T6, 2025-05-01, 2025-05-05

When frequency changes, antenna type and recommended length vary :

python .\FreqToAntSize.py <freq_hz>

#λ (m) : X.XXXX
#Ant (cm) : YYY.YYYY

This exemple encrypt de message "test" using the AES256 algorithm with CBC mode :

python ./MsgToCypher.py enc test 9CEA372979FFDCBA028BD523A3F43A44B527DE31E2BBAE56F641D87D3F6C80BC A977EA111934D65E8A6B5AC3D52B82F8

# key: 9CEA372979FFDCBA028BD523A3F43A44B527DE31E2BBAE56F641D87D3F6C80BC
# iv: A977EA111934D65E8A6B5AC3D52B82F8
# cipherText: EFAADCF7EA0A786EF7B4EF7504605970

Convert to CW and write an IQ file, specify AM or FM modulation to make Morse code audible :

python ./CWToCS8.py EFAADCF7EA0A786EF7B4EF7504605970 test-to-transmit.cs8 AM
python ./ReadCS8.py test-to-transmit.cs8

Transmit with HackRF_transfer (adjust LNA, VGA, AMP, frequence, fileName etc.) :

 hackrf_transfer -s 8000000 -x 47 -g 60 -l 40 -a 1 -f 26975000 -b 1750000 -t .\test-to-transmit.cs8

You can simply listen to or read the waterfall :

For further analysis, here is the HackRF_transfer command to write the signal in an IQ file (adjust LNA and VGA) and visualize it :

hackrf_transfer -s 8000000 -f <freq_hz> -b 1750000 -a 1 -l 24 -g 12 -r test-recvd.cs8
python ./ReadCS8.py .\test-recvd.cs8

python ./MsgToCypher.py dec EFAADCF7EA0A786EF7B4EF7504605970 9CEA372979FFDCBA028BD523A3F43A44B527DE31E2BBAE56F641D87D3F6C80BC A977EA111934D65E8A6B5AC3D52B82F8

# message: test

• version: 3.13.2.
• Virtual Env and dependencies: read requirement.txt

• Binaries: 2024.02.1
• Firmware Version: 2024.02.1

• Special thanks to @jboone for his original Morse script.

• Support this effort and give back by sponsoring on GitHub!