documentation/docs/dev_guide/gpg_key.md

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Generate GPG Key

🔐 How to Generate a GPG Key on Snigdha OS

GPG (GNU Privacy Guard) is a tool for secure communication and data encryption. It allows you to create and manage public and private keys, encrypt files, and sign documents. Here’s how you can generate a GPG key on Snigdha OS, step by step, with examples.

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🛠️ Step 1: Install GPG

Most Snigdha OS installations come with GPG pre-installed. If it’s not installed, use the following command to install it:

sudo pacman -S gnupg

To verify the installation, check the version:

gpg --version

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🛠️ Step 2: Create a New GPG Key Pair

1. Start the key generation process:

   Run the following command:

   gpg --full-generate-key
   

2. Select the key type:

   You’ll see a prompt to choose the type of key. Options typically include:

   • (1) RSA and RSA (default)
   • (2) DSA and Elgamal
   • (3) DSA (sign only)
   • (4) RSA (sign only)

   Press 1 and hit Enter to select the default RSA and RSA type.

3. Set the key length:

   You’ll be prompted to specify the key size. A common recommendation is 4096 bits for strong encryption. Type 4096 and press Enter.

4. Set the expiration date:

   You can define how long the key should be valid. Options include:

   • 0 for no expiration
   • Specify a duration, e.g., 1y for one year, 2y for two years, or 1m for one month.

   For this example, type 0 (no expiration) and press Enter. When prompted, confirm your choice.

5. Enter your details:

   You’ll be asked for:

   • Your real name: Enter your full name.
   • Your email address: Enter a valid email address.
   • A comment (optional): Add a description or leave it blank.

   Example:

   Real name: John Doe
   Email address: johndoe@example.com
   Comment: Snigdha OS User
   

   Review the details and confirm by typing O (for OK).

6. Set a passphrase:

   Choose a strong passphrase to protect your private key. This passphrase will be required whenever you use your private key for encryption or signing.

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🛠️ Step 3: Verify the Generated Key

Once the key is generated, you can list your keys with:

gpg --list-keys

Output:

/home/username/.gnupg/pubring.kbx
---------------------------------
pub   rsa4096 2023-12-05 [SC] [expires: 2025-12-05]
      ABCD1234EFGH5678IJKL9012MNOP3456QRST7890
uid           [ultimate] John Doe <johndoe@example.com>
sub   rsa4096 2023-12-05 [E] [expires: 2025-12-05]

• pub: Your primary key (for signing and certification).
• sub: Subkey (for encryption).
• [SC]: Key capabilities: Sign and Certify.
• [E]: Encryption.

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🛠️ Step 4: Export Your Public Key

To share your public key with others, export it:

gpg --armor --export johndoe@example.com > public_key.asc

This creates a file public_key.asc with your public key in ASCII format.

To display the key in the terminal:

gpg --armor --export johndoe@example.com

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🛠️ Step 5: Test Encryption and Decryption

1. Encrypt a file:

   Create a sample file to encrypt:

   echo "Hello, this is a test message!" > message.txt
   

   Encrypt the file with your public key:

   gpg --output message.txt.gpg --encrypt --recipient johndoe@example.com message.txt
   

   This generates an encrypted file message.txt.gpg.

2. Decrypt the file:

   Decrypt the file using your private key:

   gpg --output decrypted_message.txt --decrypt message.txt.gpg
   

   Enter your passphrase when prompted. The decrypted content will be saved in decrypted_message.txt.

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🛠️ Step 6: Back Up Your Keys

Always back up your keys to prevent losing access:

1. Export your private key:

   gpg --armor --export-secret-keys johndoe@example.com > private_key.asc
   

2. Export your public key:

   gpg --armor --export johndoe@example.com > public_key.asc
   

3. Store these files (private_key.asc and public_key.asc) in a safe place.

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🚀 Final Tips

• Keep your private key secure. Never share it.
• Regularly update your passphrase for added security.
• Use tools like gpg-agent for easier key management.

That’s it! You now have a functional GPG key pair set up on Snigdha OS. 🎉