diff --git a/tz/avx.go b/tz/avx.go
index 2a4d62b..4e0a2fa 100644
--- a/tz/avx.go
+++ b/tz/avx.go
@@ -1,6 +1,3 @@
-// Copyright 2018 (c) NSPCC
-//
-// This file contains AVX implementation.
 package tz
 
 import (
diff --git a/tz/avx2.go b/tz/avx2.go
index 8ee9d00..48c7025 100644
--- a/tz/avx2.go
+++ b/tz/avx2.go
@@ -1,6 +1,3 @@
-// Copyright 2019 (c) NSPCC
-//
-// This file contains AVX2 implementation.
 package tz
 
 import (
diff --git a/tz/avx2_inline.go b/tz/avx2_inline.go
index 26b5b91..eb30a9a 100644
--- a/tz/avx2_inline.go
+++ b/tz/avx2_inline.go
@@ -1,7 +1,3 @@
-// Copyright 2019 (c) NSPCC
-//
-// This file contains AVX2 implementation with inlined
-// assembly calls.
 package tz
 
 import (
diff --git a/tz/avx_inline.go b/tz/avx_inline.go
index a6374e3..a023be5 100644
--- a/tz/avx_inline.go
+++ b/tz/avx_inline.go
@@ -1,6 +1,3 @@
-// Copyright 2018 (c) NSPCC
-//
-// This file contains AVX implementation.
 package tz
 
 import (
diff --git a/tz/hash.go b/tz/hash.go
index 6bd3ce9..a7e4e4e 100644
--- a/tz/hash.go
+++ b/tz/hash.go
@@ -1,6 +1,7 @@
-// Copyright 2018 (c) NSPCC
+// Package tz contains Tillich-Zemor checksum implementations
+// using different backends.
 //
-// Package tz implements general Tillich-Zemo
+// Copyright 2022 (c) NSPCC
 package tz
 
 import (