--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test_crypting.py	Mon Sep 15 11:37:51 2025 +0200
@@ -0,0 +1,39 @@
+"""
+Check PDF encryption:
+* make a PDF with owber and user passwords
+* open and decrypt as owner or user
+"""
+import pymupdf
+
+
+def test_encryption():
+    text = "some secret information"  # keep this data secret
+    perm = int(
+        pymupdf.PDF_PERM_ACCESSIBILITY  # always use this
+        | pymupdf.PDF_PERM_PRINT  # permit printing
+        | pymupdf.PDF_PERM_COPY  # permit copying
+        | pymupdf.PDF_PERM_ANNOTATE  # permit annotations
+    )
+    owner_pass = "owner"  # owner password
+    user_pass = "user"  # user password
+    encrypt_meth = pymupdf.PDF_ENCRYPT_AES_256  # strongest algorithm
+    doc = pymupdf.open()  # empty pdf
+    page = doc.new_page()  # empty page
+    page.insert_text((50, 72), text)  # insert the data
+    tobytes = doc.tobytes(
+        encryption=encrypt_meth,  # set the encryption method
+        owner_pw=owner_pass,  # set the owner password
+        user_pw=user_pass,  # set the user password
+        permissions=perm,  # set permissions
+    )
+    doc.close()
+    doc = pymupdf.open("pdf", tobytes)
+    assert doc.needs_pass
+    assert doc.is_encrypted
+    rc = doc.authenticate("owner")
+    assert rc == 4
+    assert not doc.is_encrypted
+    doc.close()
+    doc = pymupdf.open("pdf", tobytes)
+    rc = doc.authenticate("user")
+    assert rc == 2