From 9d8576d397df800ac7593cb12db17d72b5c4440a Mon Sep 17 00:00:00 2001
From: Leonard Lyubich <leonard@nspcc.ru>
Date: Mon, 28 Sep 2020 16:20:44 +0300
Subject: [PATCH] [#53] util: Add SaltXOR function

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
---
 pkg/util/salt.go | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 pkg/util/salt.go

diff --git a/pkg/util/salt.go b/pkg/util/salt.go
new file mode 100644
index 0000000000..26a3fe3a4e
--- /dev/null
+++ b/pkg/util/salt.go
@@ -0,0 +1,17 @@
+package util
+
+// SaltXOR xors bits of data with salt
+// repeating salt if necessary.
+func SaltXOR(data, salt []byte) (result []byte) {
+	result = make([]byte, len(data))
+	ls := len(salt)
+	if ls == 0 {
+		copy(result, data)
+		return
+	}
+
+	for i := range result {
+		result[i] = data[i] ^ salt[i%ls]
+	}
+	return
+}