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119 lines
2.2 KiB
Markdown
119 lines
2.2 KiB
Markdown
---
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title: Encryption [GPG]
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description:
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date: 2025-02-17T09:02:06+00:00
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draft: false
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tags:
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- networking
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- tools
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author: TrudeEH
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showToc: true
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---
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## Symmetric Encryption
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- User A sends a password to user B.
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- The password is used to encrypt the messages.
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- A secure way to share the password is required.
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## Asymmetric Encryption
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- Users A and B have a public key and a private key.
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- The public keys are shared, and they are used to encrypt the messages.
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- The users can use their private keys to decrypt the messages.
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## GPG
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### Create a Set of Keys
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```Shell
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gpg --full-gen-key
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Select ECC (sign and encrypt) - The most secure option
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Select default curve
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```
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### Encrypt a File
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```Shell
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gpg --encrypt -r email@example.org <file> # Encrypt with the recipient (-r) key.
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```
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### Decrypt a File
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```Shell
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gpg --decrypt --output <file-output> <file> # Use the private key to decrypt a file.
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```
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### Encrypt a Message
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```Shell
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echo "Very safe message" | --encrypt --armor -r email@example.org
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```
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- `-armor` Saves the encrypted info in plain text. (Great for blog posts or copying/pasting)
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### Decrypt a Message
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GPG automatically figures out which private key to use. The encrypted file includes some metadata.
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```Shell
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cat encrypted-message.txt | gpg --decrypt
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```
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### Sign a Message
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Uses a public key to sign a message, making sure that the contents are not tampered with.
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```Shell
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echo "Very important message" | gpg --clearsign -u email@example.org
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```
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- `-clearsign` Is used to sign plain (clear) text.
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### Sign a File
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The signature is embedded in the file
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```Shell
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gpg --sign -u email@example.org <file>
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```
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The signature is separate from the file
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```Shell
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gpg --detach-sign -u email@example.org <file>
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```
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### Verify Signed message/file
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```Shell
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gpg --verify signed-message.txt
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# or, if detached
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gpg --verify <file.sig> <file>
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```
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### Import
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```Shell
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gpg --import public.pgp
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gpg --import private.pgp
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# To be able to use the key for encryption, it must be trusted.
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gpg --edit-key email@example.com
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> trust
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> 5
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```
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### Export
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```Shell
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gpg --output public.pgp --armor --export email@example.com
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gpg --output private.pgp --armor --export-secret-keys email@example.com
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```
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### List Keys
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```Shell
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gpg --list-keys # Same as gpg -k
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gpg --list-secret-keys
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```
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