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# Ubuntu/Debian
sudo apt-get update
sudo apt-get install gnupg

# CentOS/RHEL
sudo yum install gnupg2

# Verify installation
gpg --version

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# Using Chocolatey
choco install gnupg

# Direct download
# https://www.gnupg.org/download/

# Verify installation
gpg --version

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# Using Homebrew
brew install gnupg

# Verify installation
gpg --version

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# Generate RSA key pair
gpg --full-generate-key

# Generate with specific parameters
gpg --batch --full-generate-key <<EOF
Key-Type: RSA
Key-Length: 4096
Subkey-Type: RSA
Subkey-Length: 4096
Name-Real: John Doe
Name-Email: john@example.com
Expire-Date: 2y
Passphrase: my_secure_password
EOF

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# Generate ECC key
gpg --expert --full-generate-key

# Select option 9 (ECC and ECC)
# Select curve (Curve 25519, P-256, P-384, P-521)

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# List public keys
gpg --list-keys

# List private keys
gpg --list-secret-keys

# List with details
gpg --list-keys --with-colons

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# Export public key
gpg --armor --export john@example.com > public.key

# Export private key
gpg --armor --export-secret-keys john@example.com > private.key

# Import key
gpg --import public.key

# Import private key
gpg --import private.key

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# Generate revocation certificate
gpg --output revoke.asc --gen-revoke john@example.com

# Apply revocation
gpg --import revoke.asc

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# Encrypt file symmetrically
gpg --symmetric --cipher-algo AES256 file.txt

# Decrypt file
gpg --decrypt file.txt.gpg > file.txt

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# Encrypt for specific recipient
gpg --encrypt --recipient john@example.com file.txt

# Encrypt and sign
gpg --encrypt --sign --recipient john@example.com file.txt

# Decrypt file
gpg --decrypt file.txt.gpg > file.txt

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# Sign file
gpg --sign file.txt

# Sign with separate output
gpg --detach-sign file.txt

# Sign and encrypt
gpg --sign --encrypt --recipient john@example.com file.txt

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# Verify signature
gpg --verify file.txt.sig file.txt

# Verify attached signature
gpg --verify file.txt.gpg

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# Create configuration file
mkdir -p ~/.gnupg
cat > ~/.gnupg/gpg.conf <<EOF
# GnuPG configuration
default-key john@example.com
keyserver hkp://keys.openpgp.org
keyserver-options auto-key-retrieve
personal-cipher-preferences AES256 AES192 AES
personal-digest-preferences SHA512 SHA384 SHA256
cert-digest-algo SHA512
default-preference-list SHA512 SHA384 SHA256 AES256 AES192 AES
EOF

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# Start GPG agent
gpg-agent --daemon

# Configure agent
cat > ~/.gnupg/gpg-agent.conf <<EOF
default-cache-ttl 600
max-cache-ttl 7200
pinentry-program /usr/bin/pinentry-gtk-2
EOF

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# Install Enigmail in Thunderbird
# Configure email account
# Generate key pair
# Configure automatic encryption

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# Configure Mutt with GPG
set crypt_use_gpgme=yes
set crypt_autosign=yes
set crypt_replysign=yes
set crypt_replyencrypt=yes

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#!/bin/bash
# Script to encrypt files

if [ $# -eq 0 ]; then
    echo "Usage: $0 <file>"
    exit 1
fi

FILE=$1
RECIPIENT="john@example.com"

# Encrypt file
gpg --encrypt --sign --recipient $RECIPIENT "$FILE"

echo "Encrypted file: ${FILE}.gpg"

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#!/bin/bash
# Script to decrypt files

if [ $# -eq 0 ]; then
    echo "Usage: $0 <file.gpg>"
    exit 1
fi

FILE=$1

# Decrypt file
gpg --decrypt "$FILE" > "${FILE%.gpg}"

echo "Decrypted file: ${FILE%.gpg}"

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#!/bin/bash
# Encrypted backup script

BACKUP_DIR="/home/user/backup"
ENCRYPTED_DIR="/home/user/backup_encrypted"
RECIPIENT="john@example.com"

# Create encrypted backup directory
mkdir -p "$ENCRYPTED_DIR"

# Encrypt backup files
for file in "$BACKUP_DIR"/*; do
    if [ -f "$file" ]; then
        gpg --encrypt --recipient "$RECIPIENT" --output "$ENCRYPTED_DIR/$(basename "$file").gpg" "$file"
    fi
done

echo "Encrypted backup completed"

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# Sign another person's key
gpg --sign-key john@example.com

# Verify key signatures
gpg --check-sigs john@example.com

# Edit trust
gpg --edit-key john@example.com
# Command: trust

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# Upload public key
gpg --send-keys --keyserver keys.openpgp.org 0x12345678

# Search key on server
gpg --search-keys john@example.com

# Receive updated key
gpg --recv-keys 0x12345678

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# Verify configuration
gpg --version --verbose

# Verify keys
gpg --list-keys --with-colons

# Verify signatures
gpg --check-sigs

# Verify configuration
gpg --dump-options