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// The sym command encrypts or decrypts files with a password.
//
// Sym has two subcommands, enc and dec, which perform encryption and
// decryption. The encryption key is derived from the user's password
// using argon2, and the data is then encrypted using ChaCha20-Poly1305
// in chunks of 1MiB.
//
// Run sym -h for detailed usage information.
//
// # Disclaimer
//
// PLEASE DO NOT USE THIS PROGRAM. It was written for me to learn about
// symmetric encryption, and likely contains critical
// security vulnerabilities.
package main
import (
"context"
"errors"
"flag"
"fmt"
"io"
"os"
"github.com/google/subcommands"
)
var errUsage = errors.New("usage error")
type usageError struct {
msg string
}
func usageErr(format string, args ...any) error {
return &usageError{msg: fmt.Sprintf(format, args...)}
}
func (e *usageError) Error() string {
return e.msg
}
func (e *usageError) Is(target error) bool { return target == errUsage }
func registerCommands(commander *subcommands.Commander, passwordIn func() (string, error), passwordOut io.Writer, stdin io.Reader, stdout io.Writer) {
commander.Register(&encCmd{
passwordIn: passwordIn,
passwordOut: passwordOut,
stdin: stdin,
stdout: stdout,
}, "")
commander.Register(&decCmd{
passwordIn: passwordIn,
stdin: stdin,
stdout: stdout,
}, "")
commander.Register(commander.HelpCommand(), "")
commander.Explain = func(w io.Writer) {
fmt.Fprintf(w, `usage: sym <subcommand> [OPTION]... [FILE]...
Encrypt or decrypt files using a password.
Subcommands:
enc encrypt
dec decrypt
Try sym <subcommand> -h for command-specific help.
`)
}
}
func main() {
ctx := context.Background()
registerCommands(subcommands.DefaultCommander, termReadPassword, os.Stderr, os.Stdin, os.Stdout)
flag.Parse()
os.Exit(int(subcommands.Execute(ctx)))
}
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