diff --git a/src/core/crypto.js b/src/core/crypto.js
index f08aa6501..4cce979cf 100644
--- a/src/core/crypto.js
+++ b/src/core/crypto.js
@@ -1857,14 +1857,14 @@ const CipherTransformFactory = (function CipherTransformFactoryClosure() {
         return new CipherTransform(
           buildCipherConstructor(
             this.cf,
-            this.stmf,
+            this.strf,
             num,
             gen,
             this.encryptionKey
           ),
           buildCipherConstructor(
             this.cf,
-            this.strf,
+            this.stmf,
             num,
             gen,
             this.encryptionKey
diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
index 2c0abecc0..670715765 100644
--- a/test/pdfs/.gitignore
+++ b/test/pdfs/.gitignore
@@ -532,3 +532,4 @@
 !issue15053.pdf
 !bug1675139.pdf
 !issue15092.pdf
+!bug1782186.pdf
diff --git a/test/pdfs/bug1782186.pdf b/test/pdfs/bug1782186.pdf
new file mode 100755
index 000000000..450b715a9
Binary files /dev/null and b/test/pdfs/bug1782186.pdf differ
diff --git a/test/test_manifest.json b/test/test_manifest.json
index b9d1d9a92..5589c8c66 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -6868,5 +6868,12 @@
    "lastPage": 2,
    "type": "eq",
    "annotations": true
+   },
+   { "id": "bug1782186",
+   "file": "pdfs/bug1782186.pdf",
+   "password": "Hello",
+   "md5": "8505033d63625dfd77e90a3722b0c316",
+   "rounds": 1,
+   "type": "eq"
    }
 ]