diff --git a/include/sys/skein.h b/include/sys/skein.h
index 3359d48af..c21dbd95a 100644
--- a/include/sys/skein.h
+++ b/include/sys/skein.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: LicenseRef-OpenZFS-ThirdParty-PublicDomain
 /*
  * Interface declarations for Skein hashing.
  * Source code author: Doug Whiting, 2008.
diff --git a/module/icp/algs/skein/skein.c b/module/icp/algs/skein/skein.c
index 41ed2dd44..1bbf87a1d 100644
--- a/module/icp/algs/skein/skein.c
+++ b/module/icp/algs/skein/skein.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: LicenseRef-OpenZFS-ThirdParty-PublicDomain
 /*
  * Implementation of the Skein hash function.
  * Source code author: Doug Whiting, 2008.
diff --git a/module/icp/algs/skein/skein_block.c b/module/icp/algs/skein/skein_block.c
index 3ad52da5f..95355e9d4 100644
--- a/module/icp/algs/skein/skein_block.c
+++ b/module/icp/algs/skein/skein_block.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: LicenseRef-OpenZFS-ThirdParty-PublicDomain
 /*
  * Implementation of the Skein block functions.
  * Source code author: Doug Whiting, 2008.
diff --git a/module/icp/algs/skein/skein_impl.h b/module/icp/algs/skein/skein_impl.h
index eff19ce83..55463b8cb 100644
--- a/module/icp/algs/skein/skein_impl.h
+++ b/module/icp/algs/skein/skein_impl.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: LicenseRef-OpenZFS-ThirdParty-PublicDomain
 /*
  * Internal definitions for Skein hashing.
  * Source code author: Doug Whiting, 2008.
diff --git a/module/icp/algs/skein/skein_iv.c b/module/icp/algs/skein/skein_iv.c
index 84cefe454..19e10e56c 100644
--- a/module/icp/algs/skein/skein_iv.c
+++ b/module/icp/algs/skein/skein_iv.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: LicenseRef-OpenZFS-ThirdParty-PublicDomain
 /*
  * Pre-computed Skein IVs
  *
diff --git a/module/icp/algs/skein/skein_port.h b/module/icp/algs/skein/skein_port.h
index 96d1266d0..3339aac07 100644
--- a/module/icp/algs/skein/skein_port.h
+++ b/module/icp/algs/skein/skein_port.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: LicenseRef-OpenZFS-ThirdParty-PublicDomain
 /*
  * Platform-specific definitions for Skein hash function.
  *
diff --git a/module/zfs/vdev_draid_rand.c b/module/zfs/vdev_draid_rand.c
index fe1a75c11..c6a2cc3c8 100644
--- a/module/zfs/vdev_draid_rand.c
+++ b/module/zfs/vdev_draid_rand.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: LicenseRef-OpenZFS-ThirdParty-PublicDomain
 /*
  * Xorshift Pseudo Random Number Generator based on work by David Blackman
  * and Sebastiano Vigna (vigna@acm.org).