Symmetric Encryption & Decryption

🔐 What Is Symmetric Encryption?

Symmetric encryption is a method of securing data where the same password is used to both encrypt and decrypt information.

Unlike asymmetric encryption, which uses a public/private key pair, symmetric encryption relies on a single shared secret (the password). This approach is:

• ✅ Fast and efficient
• ✅ Ideal for large files or quick one-time sharing
• ❗ Best used when both parties can safely share the password

📌 If someone intercepts the password, the encrypted data is no longer secure — so always handle password exchange carefully.

🔄 How It Works

1. You choose a strong password.
2. That password is used to encrypt the data.
3. Anyone with the same password can decrypt it.
4. No key pair is required — only the shared password.

📎 Encryption security depends entirely on the strength and secrecy of the password used.

✍️ Encrypting Data Symmetrically

To encrypt text using symmetric encryption in GpgFrontend (v2.1.9 and later):

Enable Symmetric Encryption Feature

1. Go to the Settings.
2. Under the Appearance tab, check the Sym. Encrypt checkbox to enable symmetric encryption functionality.

Access the Symmetric Encryption Button

1. After enabling, you’ll see a dedicated Sym. Encrypt button on the main interface.

Enter the Text or Select a File

• Input the plaintext you wish to protect in the text editor.
• Select a file to encrypt using the file panel.

Symmetric Encryption

1. Without selecting any public key, click the Sym. Encrypt button.
2. When prompted, enter a strong, unique password.
3. This password becomes your encryption key.
4. The text or file will be encrypted into ciphertext.
5. You can save or share the encrypted result.

🔐 The recipient will need the exact same password to decrypt the message.

🔓 Decrypting Symmetric Encrypted Data

To decrypt content that was encrypted symmetrically:

1. Paste the Ciphertext: The message should begin with -----BEGIN PGP MESSAGE----- and end with -----END PGP MESSAGE-----.
2. Initiate Decryption: Choose to decrypt the message.
3. Enter the Password: Input the same password that was used for encryption.
4. View the Plaintext: If the password is correct, the original message will be revealed.

🧠 If the password is incorrect or mistyped, decryption will fail.

💡 When to Use Symmetric Encryption?

Symmetric encryption is a great choice when:

• You’re encrypting something for yourself (e.g. storing private notes or backup files).
• You’re sharing data over a secure channel, and can safely provide the password.
• You don’t want to manage public/private key infrastructure.

However, it is not ideal for public communication where secure password exchange is difficult.

🛡️ Tips for Better Security

• Always use a strong, complex password (longer is better).
• Never send passwords through insecure channels (e.g., unencrypted email).
• Consider using symmetric encryption as a supplement to public-key encryption — e.g., encrypt a file symmetrically, then encrypt the password with the recipient’s public key.