diff --git a/ssh-restrictions.md b/ssh-restrictions.md
new file mode 100644
index 0000000..372aa03
--- /dev/null
+++ b/ssh-restrictions.md
@@ -0,0 +1,4 @@
+allow command `cat /path/to/files/certificate.crt` using the specified SSH key:\
+`command="cat /path/to/files/certificate.crt",restrict ssh-ed25519 AAAAC3Nza...[key_content]... server-a`
+
+make user with no permissions and put ^ in `.ssh/authorized_keys`
\ No newline at end of file