diff --git a/scripts/ci.requirements.txt b/scripts/ci.requirements.txt
index 7dbcfe8..69c2db0 100644
--- a/scripts/ci.requirements.txt
+++ b/scripts/ci.requirements.txt
@@ -18,3 +18,7 @@
 # for mypy and pylint under Python 3.5, and we also get something good enough
 # to run audit-validity-dates.py on Python >=3.6.
 cryptography # >= 35.0.0
+
+# For building `tests/data_files/server9-bad-saltlen.crt` and check python
+# files.
+asn1crypto
diff --git a/scripts/maintainer.requirements.txt b/scripts/maintainer.requirements.txt
index dd28264..b149921 100644
--- a/scripts/maintainer.requirements.txt
+++ b/scripts/maintainer.requirements.txt
@@ -8,6 +8,3 @@
 # For building some test vectors
 pycryptodomex
 pycryptodome-test-vectors
-
-# For building `tests/data_files/server9-bad-saltlen.crt`
-asn1crypto