filer: option to encrypt data on volume server

weed/util/cipher.go

@@ -0,0 +1,60 @@
+package util
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"errors"
+	"io"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+)
+
+type CipherKey []byte
+
+func GenCipherKey() CipherKey {
+	key := make([]byte, 32)
+	if _, err := io.ReadFull(rand.Reader, key); err != nil {
+		glog.Fatalf("random key gen: %v", err)
+	}
+	return CipherKey(key)
+}
+
+func Encrypt(plaintext []byte, key CipherKey) ([]byte, error) {
+	c, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	gcm, err := cipher.NewGCM(c)
+	if err != nil {
+		return nil, err
+	}
+
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
+		return nil, err
+	}
+
+	return gcm.Seal(nonce, nonce, plaintext, nil), nil
+}
+
+func Decrypt(ciphertext []byte, key CipherKey) ([]byte, error) {
+	c, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	gcm, err := cipher.NewGCM(c)
+	if err != nil {
+		return nil, err
+	}
+
+	nonceSize := gcm.NonceSize()
+	if len(ciphertext) < nonceSize {
+		return nil, errors.New("ciphertext too short")
+	}
+
+	nonce, ciphertext := ciphertext[:nonceSize], ciphertext[nonceSize:]
+	return gcm.Open(nil, nonce, ciphertext, nil)
+}