diff --git a/requirements.txt b/requirements.txt
index 5b735f00..c12daf8e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,6 +11,6 @@ termcolor
 colorlog
 pycryptodomex
 cryptography
-asn1tools
+git+https://github.com/osmocom/asn1tools
 packaging
 git+https://github.com/hologram-io/smpp.pdu