diff --git a/irctest/irc_utils/sasl.py b/irctest/irc_utils/sasl.py
new file mode 100644
index 0000000..8bf075c
--- /dev/null
+++ b/irctest/irc_utils/sasl.py
@@ -0,0 +1,6 @@
+import base64
+
+def sasl_plain_blob(username, passphrase):
+    blob = base64.b64encode(b'\x00'.join((username.encode('utf-8'), username.encode('utf-8'), passphrase.encode('utf-8'))))
+    blobstr = blob.decode('ascii')
+    return f'AUTHENTICATE {blobstr}'