mirror of https://github.com/schollz/croc.git
132 lines
2.9 KiB
Go
132 lines
2.9 KiB
Go
package croc
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"crypto/sha1"
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"crypto/sha256"
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"fmt"
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mathrand "math/rand"
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"os"
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"strings"
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"time"
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log "github.com/cihub/seelog"
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"github.com/mars9/crypt"
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"github.com/schollz/mnemonicode"
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"golang.org/x/crypto/pbkdf2"
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)
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func init() {
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mathrand.Seed(time.Now().UTC().UnixNano())
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}
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func getRandomName() string {
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result := []string{}
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bs := make([]byte, 4)
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rand.Read(bs)
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result = mnemonicode.EncodeWordList(result, bs)
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return strings.Join(result, "-")
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}
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type encryption struct {
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Encrypted, Salt, IV []byte
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}
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func encrypt(plaintext []byte, passphrase []byte, dontencrypt ...bool) encryption {
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if len(dontencrypt) > 0 && dontencrypt[0] {
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return encryption{
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Encrypted: plaintext,
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Salt: []byte("salt"),
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IV: []byte("iv"),
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}
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}
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key, saltBytes := deriveKey(passphrase, nil)
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ivBytes := make([]byte, 12)
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// http://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf
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// Section 8.2
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rand.Read(ivBytes)
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b, _ := aes.NewCipher(key)
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aesgcm, _ := cipher.NewGCM(b)
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encrypted := aesgcm.Seal(nil, ivBytes, plaintext, nil)
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return encryption{
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Encrypted: encrypted,
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Salt: saltBytes,
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IV: ivBytes,
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}
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}
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func (e encryption) decrypt(passphrase []byte, dontencrypt ...bool) (plaintext []byte, err error) {
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if len(dontencrypt) > 0 && dontencrypt[0] {
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return e.Encrypted, nil
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}
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key, _ := deriveKey(passphrase, e.Salt)
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b, _ := aes.NewCipher(key)
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aesgcm, _ := cipher.NewGCM(b)
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plaintext, err = aesgcm.Open(nil, e.IV, e.Encrypted, nil)
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return
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}
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func deriveKey(passphrase []byte, salt []byte) ([]byte, []byte) {
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if salt == nil {
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salt = make([]byte, 8)
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// http://www.ietf.org/rfc/rfc2898.txt
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// Salt.
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rand.Read(salt)
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}
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return pbkdf2.Key([]byte(passphrase), salt, 1000, 32, sha256.New), salt
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}
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func hash(data string) string {
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return hashBytes([]byte(data))
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}
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func hashBytes(data []byte) string {
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sum := sha256.Sum256(data)
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return fmt.Sprintf("%x", sum)
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}
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func encryptFile(inputFilename string, outputFilename string, password []byte) error {
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return cryptFile(inputFilename, outputFilename, password, true)
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}
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func decryptFile(inputFilename string, outputFilename string, password []byte) error {
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return cryptFile(inputFilename, outputFilename, password, false)
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}
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func cryptFile(inputFilename string, outputFilename string, password []byte, encrypt bool) error {
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in, err := os.Open(inputFilename)
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if err != nil {
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return err
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}
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defer in.Close()
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out, err := os.Create(outputFilename)
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if err != nil {
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return err
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}
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defer func() {
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if err := out.Sync(); err != nil {
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log.Error(err)
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}
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if err := out.Close(); err != nil {
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log.Error(err)
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}
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}()
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c := &crypt.Crypter{
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HashFunc: sha1.New,
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HashSize: sha1.Size,
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Key: crypt.NewPbkdf2Key(password, 32),
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}
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if encrypt {
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if err := c.Encrypt(out, in); err != nil {
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return err
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}
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} else {
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if err := c.Decrypt(out, in); err != nil {
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return err
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}
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}
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return nil
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}
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