Encrypt and decrypt archives

README.md

@@ -67,6 +67,32 @@ Listing the contents of an archive:
 $ aar list -f archive.aarch
 ```
 
+Encrypting an archive:
+
+```bash
+$ aar encrypt -f archive.aarch
+Password: <password>
+```
+
+Where `<password>` is the password you want to use to encrypt the archive, with a minimum length of 8 characters.
+It removes the original _.aarch_ file and creates a new one with the encrypted data, with extension _.aarch.enc_.
+
+> [!NOTE]
+> The encryption is done using the AES-256-GCM algorithm, and it only works for angel archives.
+
+Decrypting an archive:
+
+```bash
+$ aar decrypt -f archive.aarch.enc
+Password: <password>
+```
+
+Where `<password>` is the password you used to encrypt the archive.
+It removes the encrypted _.aarch.enc_ file and creates a new one with the decrypted data, with extension _.aarch_.
+
+> [!NOTE]
+> The decryption is done using the AES-256-GCM algorithm, and it only works for encrypted angel archives.
+
 ## File Format
 
 ### Archive Header

cmd/aar/main.go

@@ -4,8 +4,10 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"syscall"
 
 	"github.com/angelsolaorbaiceta/aar/cmd"
+	"golang.org/x/term"
 )
 
 func main() {
@@ -19,6 +21,12 @@ func main() {
 
 		listCmd          = flag.NewFlagSet("list", flag.ExitOnError)
 		listFileNameFlag = listCmd.String("f", "", "Filename of the archive to list")
+
+		encryptCmd          = flag.NewFlagSet("encrypt", flag.ExitOnError)
+		encryptFileNameFlag = encryptCmd.String("f", "", "Filename of the archive to encrypt")
+
+		decryptCmd          = flag.NewFlagSet("decrypt", flag.ExitOnError)
+		decryptFileNameFlag = decryptCmd.String("f", "", "Filename of the archive to decrypt")
 	)
 
 	if len(os.Args) < 2 {
@@ -48,6 +56,20 @@ func main() {
 		validateFileName(*listFileNameFlag)
 		cmd.ListArchive(*listFileNameFlag)
 
+	case "encrypt":
+		encryptCmd.Parse(os.Args[2:])
+		validateFileName(*encryptFileNameFlag)
+		password := promptPassword()
+
+		cmd.EncryptArchive(*encryptFileNameFlag, password)
+
+	case "decrypt":
+		decryptCmd.Parse(os.Args[2:])
+		validateFileName(*decryptFileNameFlag)
+		password := promptPassword()
+
+		cmd.DecryptArchive(*decryptFileNameFlag, password)
+
 	default:
 		fmt.Fprintf(os.Stderr, "Usage: aar <command> [options]\n")
 		os.Exit(1)
@@ -69,3 +91,28 @@ func createArchive(fileName string, fileNames []string) {
 
 	cmd.CreateArchive(fileName, fileNames)
 }
+
+func promptPassword() string {
+	fmt.Print("Password: ")
+
+	// Disable input echoing
+	passwordBytes, err := term.ReadPassword(int(syscall.Stdin))
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error reading password: %v\n", err)
+		os.Exit(1)
+	}
+
+	fmt.Println() // Move to the next line after password input
+
+	password := string(passwordBytes)
+	validatePassword(password)
+
+	return password
+}
+
+func validatePassword(password string) {
+	if len(password) < 8 {
+		fmt.Fprintf(os.Stderr, "The password must be at least 8 characters long.\n")
+		os.Exit(1)
+	}
+}

cmd/cypt.go

@@ -0,0 +1,107 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/angelsolaorbaiceta/aar/archive"
+)
+
+func EncryptArchive(fileName, password string) {
+	// Read the archive
+	reader, err := os.OpenFile(fileName, os.O_RDONLY, 0)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error opening archive file: %v\n", err)
+		os.Exit(1)
+	}
+
+	arch, err := archive.ReadArchive(reader)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error reading archive: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Encrypt the archive
+	encArch, err := arch.Encrypt(password)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error encrypting archive: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Write the encrypted archive to disk
+	encFileName := fileName + ".enc"
+	encFile, err := os.Create(encFileName)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error creating encrypted archive file: %v\n", err)
+		os.Exit(1)
+	}
+	defer encFile.Close()
+
+	if err := encArch.Write(encFile); err != nil {
+		fmt.Fprintf(os.Stderr, "Error writing encrypted archive file: %v\n", err)
+		os.Exit(1)
+	}
+
+	fmt.Fprintf(os.Stderr, "Archive encrypted successfully to %s\n", encFileName)
+
+	// Remove the original archive
+	if err := os.Remove(fileName); err != nil {
+		fmt.Fprintf(os.Stderr, "Error removing original archive: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+func DecryptArchive(fileName, password string) {
+	// Read the encrypted archive
+	reader, err := os.OpenFile(fileName, os.O_RDONLY, 0)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error opening encrypted archive file: %v\n", err)
+		os.Exit(1)
+	}
+
+	encArch, err := archive.ReadEncryptedArchive(reader)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error reading encrypted archive: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Decrypt the archive
+	arch, err := encArch.Decrypt(password)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error decrypting archive: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Write the decrypted archive to disk
+	decFileName := decryptFileName(fileName)
+	decFile, err := os.Create(decFileName)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error creating decrypted archive file: %v\n", err)
+		os.Exit(1)
+	}
+	defer decFile.Close()
+
+	if err := arch.Write(decFile); err != nil {
+		fmt.Fprintf(os.Stderr, "Error writing decrypted archive file: %v\n", err)
+		os.Exit(1)
+	}
+
+	fmt.Fprintf(os.Stderr, "Archive decrypted successfully to %s\n", decFileName)
+
+	// Remove the encrypted archive
+	if err := os.Remove(fileName); err != nil {
+		fmt.Fprintf(os.Stderr, "Error removing encrypted archive: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+// decryptFileName returns the decrypted file name from the encrypted file name.
+// If the file name doesn't end with ".enc", it appends ".dec" to the file name.
+// Otherwise, it removes the ".enc" extension.
+func decryptFileName(fileName string) string {
+	if len(fileName) < 4 || fileName[len(fileName)-4:] != ".enc" {
+		return fileName + ".dec"
+	}
+
+	return fileName[:len(fileName)-4]
+}

go.mod

@@ -6,10 +6,12 @@ require (
 	github.com/stretchr/testify v1.9.0
 	github.com/ulikunitz/xz v0.5.12
 	golang.org/x/crypto v0.26.0
+	golang.org/x/term v0.23.0
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	golang.org/x/sys v0.23.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -8,6 +8,10 @@ github.com/ulikunitz/xz v0.5.12 h1:37Nm15o69RwBkXM0J6A5OlE67RZTfzUxTj8fB3dfcsc=
 github.com/ulikunitz/xz v0.5.12/go.mod h1:nbz6k7qbPmH4IRqmfOplQw/tblSgqTqBwxkY0oWt/14=
 golang.org/x/crypto v0.26.0 h1:RrRspgV4mU+YwB4FYnuBoKsUapNIL5cohGAmSH3azsw=
 golang.org/x/crypto v0.26.0/go.mod h1:GY7jblb9wI+FOo5y8/S2oY4zWP07AkOJ4+jxCqdqn54=
+golang.org/x/sys v0.23.0 h1:YfKFowiIMvtgl1UERQoTPPToxltDeZfbj4H7dVUCwmM=
+golang.org/x/sys v0.23.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/term v0.23.0 h1:F6D4vR+EHoL9/sWAWgAR1H2DcHr4PareCbAaCo1RpuU=
+golang.org/x/term v0.23.0/go.mod h1:DgV24QBUrK6jhZXl+20l6UWznPlwAHm1Q1mGHtydmSk=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=