satellite/orders: add EncryptionKey encryption

Add encryption using nacl/secretbox.

Change-Id: I0add31a9fd2359be1bf9d3e43b6c4b9ff3b6fb03

satellite/orders/encryptionkey.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 
 	"github.com/zeebo/errs"
+	"golang.org/x/crypto/nacl/secretbox"
 
 	"storj.io/common/storj"
 )
@@ -40,6 +41,34 @@ type EncryptionKey struct {
 	Key storj.Key
 }
 
+// When this fails to compile, then `serialToNonce` should be adjusted accordingly.
+var _ = ([16]byte)(storj.SerialNumber{})
+
+func serialToNonce(serial storj.SerialNumber) (x [24]byte) {
+	copy(x[:], serial[:])
+	return x
+}
+
+// Encrypt encrypts data and nonce using the key.
+func (key *EncryptionKey) Encrypt(plaintext []byte, nonce storj.SerialNumber) []byte {
+	out := make([]byte, 0, len(plaintext)+secretbox.Overhead)
+	n := serialToNonce(nonce)
+	k := ([32]byte)(key.Key)
+	return secretbox.Seal(out, plaintext, &n, &k)
+}
+
+// Decrypt decrypts data and nonce using the key.
+func (key *EncryptionKey) Decrypt(ciphertext []byte, nonce storj.SerialNumber) ([]byte, error) {
+	out := make([]byte, 0, len(ciphertext)-secretbox.Overhead)
+	n := serialToNonce(nonce)
+	k := ([32]byte)(key.Key)
+	dec, ok := secretbox.Open(out, ciphertext, &n, &k)
+	if !ok {
+		return nil, ErrEncryptionKey.New("unable to decrypt")
+	}
+	return dec, nil
+}
+
 // IsZero returns whether they key contains some data.
 func (key *EncryptionKey) IsZero() bool {
 	return key.ID.IsZero() || key.Key.IsZero()

satellite/orders/encryptionkey_test.go

@@ -4,12 +4,14 @@
 package orders_test
 
 import (
+	"encoding/hex"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"storj.io/common/storj"
+	"storj.io/common/testrand"
 	"storj.io/storj/satellite/orders"
 )
 
@@ -135,3 +137,79 @@ func TestEncryptionKeys_Set_Invalid(t *testing.T) {
 		assert.Error(t, err, test.Hex)
 	}
 }
+
+func randEncryptionKey() orders.EncryptionKey {
+	k := orders.EncryptionKey{}
+	r := testrand.Nonce()
+	copy(k.ID[:], r[:])
+	k.Key = testrand.Key()
+	return k
+}
+
+func TestEncryptionKey_EncryptDecrypt(t *testing.T) {
+	for i := 0; i < 10; i++ {
+		key := randEncryptionKey()
+		data := testrand.BytesInt(16)
+		serial := testrand.SerialNumber()
+
+		encrypted := key.Encrypt(data, serial)
+		require.NotEqual(t, encrypted, data)
+
+		decrypted, err := key.Decrypt(encrypted, serial)
+		require.NoError(t, err)
+		require.Equal(t, data, decrypted)
+	}
+}
+
+func TestEncryptionKey_BackwardsCompatibility(t *testing.T) {
+	type Test struct {
+		Key          string
+		DataHex      string
+		Serial       storj.SerialNumber
+		EncryptedHex string
+	}
+
+	tests := []Test{
+		{
+			Key:          "1d729566c74d1003=0d86d1e91e00167939cb6694d2c422acd208a0072939487f6999eb9d18a44784",
+			DataHex:      "045d87f3c67cf22746e995af5a253679",
+			Serial:       storj.SerialNumber{81, 186, 162, 255, 108, 212, 113, 196, 131, 241, 95, 185, 11, 173, 179, 124},
+			EncryptedHex: "5fe4c9fc734baed429afe24502ffe9d4c6efd99de5d5ae07433f7449bc55e4e1",
+		}, {
+			Key:          "5821b6d95526a41a=86216325253fec738dd7a9e28bf921119c160f0702448615bbda08313f6a8eb6",
+			DataHex:      "68d20bf5059875921e668a5bdf2c7fc4",
+			Serial:       storj.SerialNumber{132, 69, 146, 210, 87, 43, 205, 6, 104, 210, 214, 197, 47, 80, 84, 226},
+			EncryptedHex: "335eb0ab85e0624862b63c6bad78c4bdd1d52db621332773aef29b977626bcd0",
+		}, {
+			Key:          "d0836bf84c7174cb=358b0c3b525da1786f9fff094279db1944ebd7a19d0f7bbacbe0255aa5b7d44b",
+			DataHex:      "ec40f84c892b9bffd43629b0223beea5",
+			Serial:       storj.SerialNumber{244, 247, 67, 145, 244, 69, 209, 90, 253, 66, 148, 4, 3, 116, 246, 146},
+			EncryptedHex: "2615a21b9968f4fa7fdc5eb423f708a0630ec25295852e513c658eecaee0493e",
+		}, {
+			Key:          "4b98cbf8713f8d96=b586b14323a6bc8f9e7df1d929333ff993933bea6f5b3af6de0374366c4719e4",
+			DataHex:      "3a1b067d89bc7f01f1f573981659a44f",
+			Serial:       storj.SerialNumber{241, 122, 76, 114, 21, 163, 181, 57, 235, 30, 88, 73, 198, 7, 125, 187},
+			EncryptedHex: "e57f0b0e936bff96895aae6f963e0ff0a14350d2f787dda47116de0e1a7bf390",
+		}, {
+			Key:          "5722f5717a289a26=5e82ed6f4125c8fa7311e4d7defa922daae7786667f7e936cd4f24abf7df866b",
+			DataHex:      "aa56038367ad6145de1ee8f4a8b0993e",
+			Serial:       storj.SerialNumber{189, 248, 136, 58, 10, 216, 190, 156, 57, 120, 176, 72, 131, 229, 106, 21},
+			EncryptedHex: "8a238f268df2ae5a58134e2f52a813ffc157e0f12d8430268f55712c6bf8aae9",
+		},
+	}
+
+	for _, test := range tests {
+		var key orders.EncryptionKey
+		require.NoError(t, key.Set(test.Key))
+
+		data, err := hex.DecodeString(test.DataHex)
+		require.NoError(t, err)
+		encrypted, err := hex.DecodeString(test.EncryptedHex)
+		require.NoError(t, err)
+
+		decrypted, err := key.Decrypt(encrypted, test.Serial)
+		require.NoError(t, err)
+
+		require.Equal(t, data, decrypted)
+	}
+}