diff --git a/g10/ChangeLog b/g10/ChangeLog
index cffdbf3f2..d529054e5 100644
--- a/g10/ChangeLog
+++ b/g10/ChangeLog
@@ -1,3 +1,10 @@
+2004-03-26  David Shaw  <dshaw@jabberwocky.com>
+
+	* build-packet.c (calc_plaintext, do_plaintext): Do not create
+	illegal (packet header indicates a size larger than the actual
+	packet) encrypted data packets when not compressing and using a
+	filename longer than 255 characters.
+
 2004-03-25  David Shaw  <dshaw@jabberwocky.com>
 
 	* options.h, g10.c (main), compress-bz2.c (init_uncompress):
diff --git a/g10/build-packet.c b/g10/build-packet.c
index f583828a8..b3bb3f32a 100644
--- a/g10/build-packet.c
+++ b/g10/build-packet.c
@@ -528,7 +528,14 @@ do_pubkey_enc( IOBUF out, int ctb, PKT_pubkey_enc *enc )
 static u32
 calc_plaintext( PKT_plaintext *pt )
 {
-    return pt->len? (1 + 1 + pt->namelen + 4 + pt->len) : 0;
+  /* Truncate namelen to the maximum 255 characters.  Note this means
+     that a function that calls build_packet with an illegal literal
+     packet will get it back legalized. */
+
+  if(pt->namelen>255)
+    pt->namelen=255;
+
+  return pt->len? (1 + 1 + pt->namelen + 4 + pt->len) : 0;
 }
 
 static int
@@ -539,12 +546,6 @@ do_plaintext( IOBUF out, int ctb, PKT_plaintext *pt )
     byte buf[1000]; /* this buffer has the plaintext! */
     int nbytes;
 
-    /* Truncate namelen to the maximum 255 characters.  This does mean
-       that a function that calls build_packet with an illegal literal
-       packet will get it back legalized. */
-    if(pt->namelen>255)
-      pt->namelen=255;
-
     write_header(out, ctb, calc_plaintext( pt ) );
     iobuf_put(out, pt->mode );
     iobuf_put(out, pt->namelen );