OSCrypt for POSIX uses libsecret to store a randomised encryption key.

components/os_crypt/os_crypt_linux_unittest.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <string>
+
+#include "base/macros.h"
+#include "components/os_crypt/key_storage_linux.h"
+#include "components/os_crypt/os_crypt.h"
+#include "components/os_crypt/os_crypt_mocker_linux.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+class OSCryptLinuxTest : public testing::Test {
+ public:
+  OSCryptLinuxTest() = default;
+  ~OSCryptLinuxTest() override = default;
+
+  void SetUp() override {
+    OSCryptMockerLinux::SetUpWithSingleton();
+    key_storage_ = OSCryptMockerLinux::GetInstance();
+  }
+
+  void TearDown() override { OSCryptMockerLinux::TearDown(); }
+
+ protected:
+  OSCryptMockerLinux* key_storage_ = nullptr;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(OSCryptLinuxTest);
+};
+
+TEST_F(OSCryptLinuxTest, VerifyV0) {
+  const std::string originaltext = "hello";
+  std::string ciphertext;
+  std::string decipheredtext;
+
+  key_storage_->ResetTo("");
+  ciphertext = originaltext;  // No encryption
+  ASSERT_TRUE(OSCrypt::DecryptString(ciphertext, &decipheredtext));
+  ASSERT_EQ(originaltext, decipheredtext);
+}
+
+TEST_F(OSCryptLinuxTest, VerifyV10) {
+  const std::string originaltext = "hello";
+  std::string ciphertext;
+  std::string decipheredtext;
+
+  key_storage_->ResetTo("peanuts");
+  ASSERT_TRUE(OSCrypt::EncryptString(originaltext, &ciphertext));
+  key_storage_->ResetTo("not_peanuts");
+  ciphertext = ciphertext.substr(3).insert(0, "v10");
+  ASSERT_TRUE(OSCrypt::DecryptString(ciphertext, &decipheredtext));
+  ASSERT_EQ(originaltext, decipheredtext);
+}
+
+TEST_F(OSCryptLinuxTest, VerifyV11) {
+  const std::string originaltext = "hello";
+  std::string ciphertext;
+  std::string decipheredtext;
+
+  key_storage_->ResetTo("");
+  ASSERT_TRUE(OSCrypt::EncryptString(originaltext, &ciphertext));
+  ASSERT_EQ(ciphertext.substr(0, 3), "v11");
+  ASSERT_TRUE(OSCrypt::DecryptString(ciphertext, &decipheredtext));
+  ASSERT_EQ(originaltext, decipheredtext);
+}
+
+}  // namespace