diff --git a/hide-secret.cpp b/hide-secret.cpp
new file mode 100644
index 0000000..bd9eb05
--- /dev/null
+++ b/hide-secret.cpp
@@ -0,0 +1,41 @@
+#include <cstddef>
+#include <cstring>
+#include <vector>
+
+const char kSecretReplacer = 'x';
+
+void hide_secret(char* const text, const char* const secret) {
+    if (text == nullptr || secret == nullptr) {
+        return;
+    }
+
+    auto text_len = std::strlen(text);
+    auto secret_len = std::strlen(secret);
+
+    if (text_len == 0 || secret_len == 0 || text_len < secret_len) {
+        return;
+    }
+
+    std::vector<size_t> secret_start_indices{};
+    for (size_t i = 0; i < text_len - secret_len + 1; ++i) {
+        auto found_match = true;
+
+        for (size_t j = 0; j < secret_len; ++j) {
+            if (text[i+j] != secret[j]) {
+                found_match = false;
+                break;
+            }
+        }
+        if (!found_match) {
+            continue;
+        }
+
+        secret_start_indices.push_back(i);
+    }
+
+    for (const auto idx : secret_start_indices) {
+        for (size_t i = idx; i < idx + secret_len; ++i) {
+            text[i] = kSecretReplacer;
+        }
+    }
+}
diff --git a/hide-secret.hpp b/hide-secret.hpp
index b959198..a3589bd 100644
--- a/hide-secret.hpp
+++ b/hide-secret.hpp
@@ -1,2 +1 @@
 void hide_secret(char* const text, const char* const secret);
-