Add support for NaCL SecretBox

decrypt.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 
 	"golang.org/x/crypto/chacha20poly1305"
+	"golang.org/x/crypto/nacl/secretbox"
 )
 
 type aead struct {
@@ -74,3 +75,33 @@ func (p aead) GetSecret(key string) (value []byte, err error) {
 	nonce, ciphertext := value[:nonceSize], value[nonceSize:]
 	return p.aead.Open(nil, nonce, ciphertext, nil)
 }
+
+type secretBox struct {
+	Provider
+	key [32]byte
+}
+
+func WithSecretBox(p Provider, key [32]byte) Provider {
+	return &secretBox{
+		Provider: p,
+		key:      key,
+	}
+}
+
+func (p secretBox) GetSecret(key string) (value []byte, err error) {
+	if value, err = p.Provider.GetSecret(key); err != nil {
+		return
+	}
+
+	var nonce [24]byte
+	if copy(nonce[:], value) < 24 {
+		return nil, errors.New("secret: encrypted secretbox value is too short")
+	}
+
+	var ok bool
+	if value, ok = secretbox.Open(nil, value[24:], &nonce, &p.key); !ok {
+		return nil, errors.New("secret: encrypted secretbox open failed")
+	}
+
+	return
+}

decrypt_test.go

@@ -150,3 +150,38 @@ func TestWithChaCha20Poly1305X(t *testing.T) {
 		t.Errorf("expected:\n%s\n\ngot:\n%s", hex.Dump(msg), hex.Dump(v))
 	}
 }
+
+func TestWithSecretBox(t *testing.T) {
+	var (
+		key   [32]byte
+		nonce [24]byte
+		box   []byte
+	)
+	key = [32]uint8{
+		0x90, 0x93, 0x6b, 0x91, 0x79, 0xac, 0xa2, 0x0d,
+		0x7d, 0xf7, 0x8c, 0x29, 0x93, 0x5f, 0xd4, 0xf3,
+		0x9e, 0x61, 0xe3, 0x6d, 0xb0, 0x30, 0x31, 0xac,
+		0xa5, 0xd6, 0x7e, 0xb5, 0x04, 0xe8, 0x1b, 0x87,
+	}
+	nonce = [24]uint8{
+		0xaa, 0xe6, 0x05, 0x6b, 0x18, 0xb9, 0x05, 0xc8,
+		0x9e, 0x53, 0x25, 0x79, 0xbe, 0x79, 0x9d, 0x9b,
+		0xbe, 0x1e, 0x34, 0x11, 0xbb, 0x21, 0x51, 0x3c,
+	}
+	box = append(nonce[:],
+		0x8b, 0x0a, 0x66, 0x4f, 0xb3, 0x1f, 0x78, 0xfd,
+		0xcb, 0x41, 0x9e, 0x4b, 0x1a, 0x9e, 0x34, 0x20,
+		0xef, 0x2c, 0x64, 0xb3, 0x00, 0x6f, 0xf1, 0x9e,
+		0xe1, 0xbd, 0xfe, 0xd3, 0x86, 0x12, 0x8d, 0x09,
+		0x85, 0x34, 0xae, 0xa3, 0xfd)
+
+	p := WithSecretBox(environment{"test": box}, key)
+	v, err := p.GetSecret("test")
+	if err != nil {
+		t.Fatal(err)
+		return
+	}
+	if string(v) != "Hello, boxed Gophers!" {
+		t.Errorf(`expected "Hello, boxed Gophers!", got %q`, v)
+	}
+}