diff --git a/dangerzone/isolation_provider/base.py b/dangerzone/isolation_provider/base.py
index 2fc8b31..7b9866b 100644
--- a/dangerzone/isolation_provider/base.py
+++ b/dangerzone/isolation_provider/base.py
@@ -84,6 +84,14 @@ class IsolationProvider(ABC):
     def get_max_parallel_conversions(self) -> int:
         pass
 
+    def sanitize_conversion_str(self, untrusted_conversion_str: str) -> str:
+        conversion_string = replace_control_chars(untrusted_conversion_str)
+
+        # Add armor (gpg-style)
+        armor_start = "-----CONVERSION LOG START-----\n"
+        armor_end = "-----CONVERSION LOG END-----"
+        return armor_start + conversion_string + armor_end
+
 
 # From global_common:
 
diff --git a/dangerzone/isolation_provider/container.py b/dangerzone/isolation_provider/container.py
index 6f44316..75a9355 100644
--- a/dangerzone/isolation_provider/container.py
+++ b/dangerzone/isolation_provider/container.py
@@ -295,7 +295,7 @@ class Container(IsolationProvider):
             with open(log_path, "r", encoding="ascii", errors="replace") as f:
                 untrusted_log = f.read(MAX_CONVERSION_LOG_CHARS)
             log.info(
-                f"Conversion output (doc to pixels):\n{replace_control_chars(untrusted_log)}"
+                f"Conversion output (doc to pixels):\n{self.sanitize_conversion_str(untrusted_log)}"
             )
 
         if ret != 0:
diff --git a/dangerzone/isolation_provider/qubes.py b/dangerzone/isolation_provider/qubes.py
index 167858c..8b56ae5 100644
--- a/dangerzone/isolation_provider/qubes.py
+++ b/dangerzone/isolation_provider/qubes.py
@@ -145,7 +145,7 @@ class Qubes(IsolationProvider):
         if getattr(sys, "dangerzone_dev", False):
             untrusted_log = read_debug_text(p)
             log.info(
-                f"Conversion output (doc to pixels):\n{replace_control_chars(untrusted_log)}"
+                f"Conversion output (doc to pixels)\n{self.sanitize_conversion_str(untrusted_log)}"
             )
 
         # FIXME pass OCR stuff properly (see #455)