diff --git a/g13/Makefile.am b/g13/Makefile.am
index 34d5baf4b..4244a747a 100644
--- a/g13/Makefile.am
+++ b/g13/Makefile.am
@@ -45,7 +45,8 @@ g13_SOURCES = \
 	runner.c runner.h \
 	backend.c backend.h \
 	be-encfs.c be-encfs.h \
-	be-truecrypt.c be-truecrypt.h
+	be-truecrypt.c be-truecrypt.h \
+	be-dmcrypt.c be-dmcrypt.h
 
 g13_LDADD = $(libcommonpth) \
 	$(LIBGCRYPT_LIBS) $(LIBASSUAN_LIBS) $(NPTH_LIBS) \
diff --git a/g13/backend.c b/g13/backend.c
index b35887be3..bb7bfcc02 100644
--- a/g13/backend.c
+++ b/g13/backend.c
@@ -31,13 +31,15 @@
 #include "backend.h"
 #include "be-encfs.h"
 #include "be-truecrypt.h"
+#include "be-dmcrypt.h"
+#include "call-syshelp.h"
 
-
+#define no_such_backend(a) _no_such_backend ((a), __func__)
 static gpg_error_t
-no_such_backend (int conttype)
+_no_such_backend (int conttype, const char *func)
 {
-  log_error ("invalid backend %d given - this is most likely a bug\n",
-             conttype);
+  log_error ("invalid backend %d given in %s - this is most likely a bug\n",
+             conttype, func);
   return gpg_error (GPG_ERR_INTERNAL);
 }
 
@@ -81,6 +83,7 @@ be_is_supported_conttype (int conttype)
   switch (conttype)
     {
     case CONTTYPE_ENCFS:
+    case CONTTYPE_DM_CRYPT:
       return 1;
 
     default:
@@ -106,7 +109,7 @@ be_take_lock_for_create (ctrl_t ctrl, const char *fname, dotlock_t *r_lock)
   if (ctrl->conttype == CONTTYPE_DM_CRYPT)
     {
       /*  */
-      err = gpg_error (GPG_ERR_NOT_IMPLEMENTED);
+      err = call_syshelp_set_device (ctrl, fname);
       goto leave;
     }
 
@@ -186,6 +189,9 @@ be_create_new_keys (int conttype, membuf_t *mb)
     case CONTTYPE_TRUECRYPT:
       return be_truecrypt_create_new_keys (mb);
 
+    case CONTTYPE_DM_CRYPT:
+      return 0;
+
     default:
       return no_such_backend (conttype);
     }
@@ -205,6 +211,9 @@ be_create_container (ctrl_t ctrl, int conttype,
     case CONTTYPE_ENCFS:
       return be_encfs_create_container (ctrl, fname, tuples, r_id);
 
+    case CONTTYPE_DM_CRYPT:
+      return be_dmcrypt_create_container (ctrl);
+
     default:
       return no_such_backend (conttype);
     }
@@ -222,6 +231,9 @@ be_mount_container (ctrl_t ctrl, int conttype,
     case CONTTYPE_ENCFS:
       return be_encfs_mount_container (ctrl, fname, mountpoint, tuples, r_id);
 
+    case CONTTYPE_DM_CRYPT:
+      return be_dmcrypt_mount_container (ctrl, fname, mountpoint, tuples);
+
     default:
       return no_such_backend (conttype);
     }
diff --git a/g13/be-dmcrypt.c b/g13/be-dmcrypt.c
new file mode 100644
index 000000000..325567633
--- /dev/null
+++ b/g13/be-dmcrypt.c
@@ -0,0 +1,64 @@
+/* be-dmcrypt.c - The DM-Crypt based backend
+ * Copyright (C) 2015 Werner Koch
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include "g13.h"
+#include "i18n.h"
+#include "keyblob.h"
+#include "call-syshelp.h"
+#include "be-dmcrypt.h"
+
+
+/* Create the container using the current device.
+ * information in TUPLES. */
+gpg_error_t
+be_dmcrypt_create_container (ctrl_t ctrl)
+{
+  gpg_error_t err;
+
+  err = call_syshelp_run_create (ctrl, CONTTYPE_DM_CRYPT);
+
+  return err;
+}
+
+
+/* Mount the container described by the filename FNAME and the keyblob
+ * information in TUPLES.  On success the runner id is stored at R_ID. */
+gpg_error_t
+be_dmcrypt_mount_container (ctrl_t ctrl,
+                            const char *fname, const char *mountpoint,
+                            tupledesc_t tuples)
+{
+  gpg_error_t err;
+
+  err = call_syshelp_set_device (ctrl, fname);
+  if (err)
+    goto leave;
+
+  err = call_syshelp_run_mount (ctrl, CONTTYPE_DM_CRYPT, mountpoint, tuples);
+
+ leave:
+  return err;
+}
diff --git a/g13/be-dmcrypt.h b/g13/be-dmcrypt.h
new file mode 100644
index 000000000..152186057
--- /dev/null
+++ b/g13/be-dmcrypt.h
@@ -0,0 +1,32 @@
+/* be-dmcrypt.h - Public defs for the DM-Crypt based backend
+ * Copyright (C) 2015 Werner Koch
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef G13_BE_DMCRYPT_H
+#define G13_BE_DMCRYPT_H
+
+#include "backend.h"
+
+gpg_error_t be_dmcrypt_create_container (ctrl_t ctrl);
+gpg_error_t be_dmcrypt_mount_container (ctrl_t ctrl,
+                                        const char *fname,
+                                        const char *mountpoint,
+                                        tupledesc_t tuples);
+
+
+#endif /*G13_BE_DMCRYPT_H*/
diff --git a/g13/call-syshelp.c b/g13/call-syshelp.c
index 0e227ab16..0e69e9c11 100644
--- a/g13/call-syshelp.c
+++ b/g13/call-syshelp.c
@@ -44,21 +44,56 @@ struct call_syshelp_s
 };
 
 
-/* Fork off the syshelp tool if this has not already been done.  */
+/* Parameter used with the CREATE command.  */
+struct create_parm_s
+{
+  assuan_context_t ctx;
+  ctrl_t ctrl;
+  membuf_t plaintext;
+  unsigned int expect_plaintext:1;
+  unsigned int got_plaintext:1;
+};
+
+
+/* Parameter used with the MOUNT command.  */
+struct mount_parm_s
+{
+  assuan_context_t ctx;
+  ctrl_t ctrl;
+  const void *keyblob;
+  size_t keybloblen;
+};
+
+
+
+
+
+/* Fork off the syshelp tool if this has not already been done.  On
+   success stores the current Assuan context for the syshelp tool at
+   R_CTX.  */
 static gpg_error_t
-start_syshelp (ctrl_t ctrl)
+start_syshelp (ctrl_t ctrl, assuan_context_t *r_ctx)
 {
   gpg_error_t err;
   assuan_context_t ctx;
   assuan_fd_t no_close_list[3];
   int i;
 
-  if (ctrl->syshelp_local->assctx)
+  *r_ctx = NULL;
+
+  if (ctrl->syshelp_local && (*r_ctx = ctrl->syshelp_local->assctx))
     return 0; /* Already set.  */
 
   if (opt.verbose)
     log_info ("starting a new syshelp\n");
 
+  if (!ctrl->syshelp_local)
+    {
+      ctrl->syshelp_local = xtrycalloc (1, sizeof *ctrl->syshelp_local);
+      if (!ctrl->syshelp_local)
+        return gpg_error_from_syserror ();
+    }
+
   if (es_fflush (NULL))
     {
       err = gpg_error_from_syserror ();
@@ -79,38 +114,40 @@ start_syshelp (ctrl_t ctrl)
       return err;
     }
 
-  /* Call userv to start g13-syshelp.  This userv script needs tpo be
-     installed under the name "gnupg-g13-syshelp":
-
-       if ( glob service-user root
-          )
-           reset
-           suppress-args
-           execute /home/wk/b/gnupg/g13/g13-syshelp -v
-       else
-           error Nothing to do for this service-user
-       fi
-       quit
-  */
+  /* Call userv to start g13-syshelp.  This userv script needs to be
+   * installed under the name "gnupg-g13-syshelp":
+   *
+   *   if ( glob service-user root
+   *      )
+   *       reset
+   *       suppress-args
+   *       execute /home/wk/b/gnupg/g13/g13-syshelp -v
+   *   else
+   *       error Nothing to do for this service-user
+   *   fi
+   *   quit
+   */
   {
-    const char *argv[3];
+    const char *argv[4];
 
     argv[0] = "userv";
-    argv[1] = "gnupg-g13-syshelp";
-    argv[2] = NULL;
+    argv[1] = "root";
+    argv[2] = "gnupg-g13-syshelp";
+    argv[3] = NULL;
 
     err = assuan_pipe_connect (ctx, "/usr/bin/userv", argv,
                                no_close_list, NULL, NULL, 0);
   }
   if (err)
     {
-      log_error ("can't connect to '%s' - : %s\n",
-                 "g13-syshelp", gpg_strerror (err));
+      log_error ("can't connect to '%s': %s %s\n",
+                 "g13-syshelp", gpg_strerror (err), gpg_strsource (err));
       log_info ("(is userv and its gnupg-g13-syshelp script installed?)\n");
       assuan_release (ctx);
       return err;
     }
-  ctrl->syshelp_local->assctx = ctx;
+
+  *r_ctx = ctrl->syshelp_local->assctx = ctx;
 
   if (DBG_IPC)
     log_debug ("connection to g13-syshelp established\n");
@@ -129,5 +166,243 @@ call_syshelp_release (ctrl_t ctrl)
     {
       assuan_release (ctrl->syshelp_local->assctx);
       ctrl->syshelp_local->assctx = NULL;
+      xfree (ctrl->syshelp_local);
+      ctrl->syshelp_local = NULL;
     }
 }
+
+
+/* Send the DEVICE command to the syshelper.  FNAME is the name of the
+   device.  */
+gpg_error_t
+call_syshelp_set_device (ctrl_t ctrl, const char *fname)
+{
+  gpg_error_t err;
+  assuan_context_t ctx;
+  char *line = NULL;
+
+  err = start_syshelp (ctrl, &ctx);
+  if (err)
+    goto leave;
+
+  line = xtryasprintf ("DEVICE %s", fname);
+  if (!line)
+    {
+      err = gpg_error_from_syserror ();
+      goto leave;
+    }
+  err = assuan_transact (ctx, line, NULL, NULL, NULL, NULL, NULL, NULL);
+
+ leave:
+  xfree (line);
+  return err;
+}
+
+
+
+static gpg_error_t
+create_status_cb (void *opaque, const char *line)
+{
+  struct create_parm_s *parm = opaque;
+
+  if (has_leading_keyword (line, "PLAINTEXT_FOLLOWS"))
+    parm->expect_plaintext = 1;
+
+  return 0;
+}
+
+
+static gpg_error_t
+create_data_cb (void *opaque, const void *data, size_t datalen)
+{
+  struct create_parm_s *parm = opaque;
+  gpg_error_t err = 0;
+
+  if (!parm->expect_plaintext)
+    {
+      log_error ("status line for data missing\n");
+      err = gpg_error (GPG_ERR_UNEXPECTED);
+    }
+  else if (data)
+    {
+      put_membuf (&parm->plaintext, data, datalen);
+    }
+  else
+    {
+      parm->expect_plaintext = 0;
+      parm->got_plaintext = 1;
+    }
+
+  return err;
+}
+
+
+static gpg_error_t
+create_inq_cb (void *opaque, const char *line)
+{
+  struct create_parm_s *parm = opaque;
+  gpg_error_t err;
+
+  if (has_leading_keyword (line, "ENCKEYBLOB"))
+    {
+      void *plaintext;
+      size_t plaintextlen;
+
+      if (!parm->got_plaintext)
+        err = gpg_error (GPG_ERR_UNEXPECTED);
+      else if (!(plaintext = get_membuf (&parm->plaintext, &plaintextlen)))
+        err = gpg_error_from_syserror ();
+      else
+        {
+          void *ciphertext;
+          size_t ciphertextlen;
+
+          log_printhex ("plain", plaintext, plaintextlen);
+          err = g13_encrypt_keyblob (parm->ctrl,
+                                     plaintext, plaintextlen,
+                                     &ciphertext, &ciphertextlen);
+          wipememory (plaintext, plaintextlen);
+          xfree (plaintext);
+          if (err)
+            log_error ("error encrypting keyblob: %s\n", gpg_strerror (err));
+          else
+            {
+              err = assuan_send_data (parm->ctx, ciphertext, ciphertextlen);
+              xfree (ciphertext);
+              if (err)
+                log_error ("sending ciphertext to g13-syshelp failed: %s\n",
+                           gpg_strerror (err));
+            }
+        }
+    }
+  else
+    err = gpg_error (GPG_ERR_ASS_UNKNOWN_INQUIRE);
+
+  return err;
+}
+
+
+/* Run the CREATE command on the current device.  CONTTYPES gives the
+   requested content type for the new container.  */
+gpg_error_t
+call_syshelp_run_create (ctrl_t ctrl, int conttype)
+{
+  gpg_error_t err;
+  assuan_context_t ctx;
+  struct create_parm_s parm;
+
+  memset (&parm, 0, sizeof parm);
+
+  err = start_syshelp (ctrl, &ctx);
+  if (err)
+    goto leave;
+
+  /* tty_get ("waiting for debugger"); */
+  /* tty_kill_prompt (); */
+
+  parm.ctx = ctx;
+  parm.ctrl = ctrl;
+  init_membuf (&parm.plaintext, 512);
+  if (conttype == CONTTYPE_DM_CRYPT)
+    {
+      err = assuan_transact (ctx, "CREATE dm-crypt",
+                             create_data_cb, &parm,
+                             create_inq_cb, &parm,
+                             create_status_cb, &parm);
+    }
+  else
+    {
+      log_error ("invalid backend type %d given\n", conttype);
+      err = GPG_ERR_INTERNAL;
+      goto leave;
+    }
+
+ leave:
+  xfree (get_membuf (&parm.plaintext, NULL));
+  return err;
+}
+
+
+
+static gpg_error_t
+mount_status_cb (void *opaque, const char *line)
+{
+  struct mount_parm_s *parm = opaque;
+
+  /* Nothing right now.  */
+  (void)parm;
+  (void)line;
+
+  return 0;
+}
+
+
+static gpg_error_t
+mount_inq_cb (void *opaque, const char *line)
+{
+  struct mount_parm_s *parm = opaque;
+  gpg_error_t err;
+
+  if (has_leading_keyword (line, "KEYBLOB"))
+    {
+      int setconfidential = !assuan_get_flag (parm->ctx, ASSUAN_CONFIDENTIAL);
+
+      if (setconfidential)
+        assuan_begin_confidential (parm->ctx);
+      err = assuan_send_data (parm->ctx, parm->keyblob, parm->keybloblen);
+      if (setconfidential)
+        assuan_end_confidential (parm->ctx);
+      if (err)
+        log_error ("sending keyblob to g13-syshelp failed: %s\n",
+                   gpg_strerror (err));
+    }
+  else
+    err = gpg_error (GPG_ERR_ASS_UNKNOWN_INQUIRE);
+
+  return err;
+}
+
+
+/* Run the MOUNT command on the current device.  CONTTYPES gives the
+   requested content type for the new container.  MOUNTPOINT the
+   desired mount point or NULL for default.  */
+gpg_error_t
+call_syshelp_run_mount (ctrl_t ctrl, int conttype, const char *mountpoint,
+                        tupledesc_t tuples)
+{
+  gpg_error_t err;
+  assuan_context_t ctx;
+  struct mount_parm_s parm;
+
+  memset (&parm, 0, sizeof parm);
+
+  err = start_syshelp (ctrl, &ctx);
+  if (err)
+    goto leave;
+
+  /* tty_get ("waiting for debugger"); */
+  /* tty_kill_prompt (); */
+
+  parm.ctx = ctx;
+  parm.ctrl = ctrl;
+  if (conttype == CONTTYPE_DM_CRYPT)
+    {
+      ref_tupledesc (tuples);
+      parm.keyblob = get_tupledesc_data (tuples, &parm.keybloblen);
+      err = assuan_transact (ctx, "MOUNT dm-crypt",
+                             NULL, NULL,
+                             mount_inq_cb, &parm,
+                             mount_status_cb, &parm);
+      unref_tupledesc (tuples);
+    }
+  else
+    {
+      (void)mountpoint; /* Not used.  */
+      log_error ("invalid backend type %d given\n", conttype);
+      err = GPG_ERR_INTERNAL;
+      goto leave;
+    }
+
+ leave:
+  return err;
+}
diff --git a/g13/call-syshelp.h b/g13/call-syshelp.h
index c78d53b5c..60cc776a8 100644
--- a/g13/call-syshelp.h
+++ b/g13/call-syshelp.h
@@ -20,7 +20,14 @@
 #ifndef GNUPG_G13_CALL_SYSHELP_H
 #define GNUPG_G13_CALL_SYSHELP_H
 
+#include "g13tuple.h"
+
 void call_syshelp_release (ctrl_t ctrl);
+gpg_error_t call_syshelp_set_device (ctrl_t ctrl, const char *fname);
+gpg_error_t call_syshelp_run_create (ctrl_t ctrl, int conttype);
+gpg_error_t call_syshelp_run_mount (ctrl_t ctrl, int conttype,
+                                    const char *mountpoint,
+                                    tupledesc_t tuples);
 
 
 #endif /*GNUPG_G13_CALL_SYSHELP_H*/
diff --git a/g13/create.c b/g13/create.c
index fc2761877..0126f5b47 100644
--- a/g13/create.c
+++ b/g13/create.c
@@ -103,17 +103,16 @@ create_new_keyblob (ctrl_t ctrl, int is_detached,
    CTRL the result is a single OpenPGP binary message, a single
    special OpenPGP packet encapsulating a CMS message or a
    concatenation of both with the CMS packet being the last.  */
-static gpg_error_t
-encrypt_keyblob (ctrl_t ctrl, void *keyblob, size_t keybloblen,
-                 strlist_t keys,
-                 void **r_encblob, size_t *r_encbloblen)
+gpg_error_t
+g13_encrypt_keyblob (ctrl_t ctrl, void *keyblob, size_t keybloblen,
+                     void **r_encblob, size_t *r_encbloblen)
 {
   gpg_error_t err;
 
   /* FIXME:  For now we only implement OpenPGP.  */
   err = gpg_encrypt_blob (ctrl, opt.gpg_program, opt.gpg_arguments,
                           keyblob, keybloblen,
-                          keys,
+                          ctrl->recipients,
                           r_encblob, r_encbloblen);
 
   return err;
@@ -219,11 +218,10 @@ write_keyblob (const char *filename,
 
 
 /* Create a new container under the name FILENAME and intialize it
-   using the current settings.  KEYS is a list of public keys to which
-   the container will be encrypted.  If the file already exists an
-   error is returned.  */
+   using the current settings.  If the file already exists an error is
+   returned.  */
 gpg_error_t
-g13_create_container (ctrl_t ctrl, const char *filename, strlist_t keys)
+g13_create_container (ctrl_t ctrl, const char *filename)
 {
   gpg_error_t err;
   dotlock_t lock;
@@ -236,7 +234,7 @@ g13_create_container (ctrl_t ctrl, const char *filename, strlist_t keys)
   tupledesc_t tuples = NULL;
   unsigned int dummy_rid;
 
-  if (!keys)
+  if (!ctrl->recipients)
     return gpg_error (GPG_ERR_NO_PUBKEY);
 
   err = be_take_lock_for_create (ctrl, filename, &lock);
@@ -259,29 +257,32 @@ g13_create_container (ctrl_t ctrl, const char *filename, strlist_t keys)
         }
     }
 
-  /* Create a new keyblob.  */
-  err = create_new_keyblob (ctrl, !!detachedname, &keyblob, &keybloblen);
-  if (err)
-    goto leave;
+  if (ctrl->conttype != CONTTYPE_DM_CRYPT)
+    {
+      /* Create a new keyblob.  */
+      err = create_new_keyblob (ctrl, !!detachedname, &keyblob, &keybloblen);
+      if (err)
+        goto leave;
 
-  /* Encrypt that keyblob.  */
-  err = encrypt_keyblob (ctrl, keyblob, keybloblen, keys,
-                         &enckeyblob, &enckeybloblen);
-  if (err)
-    goto leave;
+      /* Encrypt that keyblob.  */
+      err = g13_encrypt_keyblob (ctrl, keyblob, keybloblen,
+                                 &enckeyblob, &enckeybloblen);
+      if (err)
+        goto leave;
 
-  /* Put a copy of the keyblob into a tuple structure.  */
-  err = create_tupledesc (&tuples, keyblob, keybloblen);
-  if (err)
-    goto leave;
-  keyblob = NULL;
-  /* if (opt.verbose) */
-  /*   dump_keyblob (tuples); */
+      /* Put a copy of the keyblob into a tuple structure.  */
+      err = create_tupledesc (&tuples, keyblob, keybloblen);
+      if (err)
+        goto leave;
+      keyblob = NULL;
+      /* if (opt.verbose) */
+      /*   dump_keyblob (tuples); */
 
-  /* Write out the header, the encrypted keyblob and some padding. */
-  err = write_keyblob (filename, enckeyblob, enckeybloblen);
-  if (err)
-    goto leave;
+      /* Write out the header, the encrypted keyblob and some padding. */
+      err = write_keyblob (filename, enckeyblob, enckeybloblen);
+      if (err)
+        goto leave;
+    }
 
   /* Create and append the container.  FIXME: We should pass the
      estream object in addition to the filename, so that the backend
diff --git a/g13/create.h b/g13/create.h
index cc4ddfd08..ec4224c40 100644
--- a/g13/create.h
+++ b/g13/create.h
@@ -20,8 +20,10 @@
 #ifndef G13_CREATE_H
 #define G13_CREATE_H
 
-gpg_error_t g13_create_container (ctrl_t ctrl, const char *filename,
-                                  strlist_t keys);
+gpg_error_t g13_encrypt_keyblob (ctrl_t ctrl,
+                                 void *keyblob, size_t keybloblen,
+                                 void **r_encblob, size_t *r_encbloblen);
+gpg_error_t g13_create_container (ctrl_t ctrl, const char *filename);
 
 
 #endif /*G13_CREATE_H*/
diff --git a/g13/g13-syshelp.c b/g13/g13-syshelp.c
index c09a5e917..cbb5f8dbf 100644
--- a/g13/g13-syshelp.c
+++ b/g13/g13-syshelp.c
@@ -270,6 +270,10 @@ main ( int argc, char **argv)
                strerror (errno));
 
   opt.homedir = default_homedir ();
+  /* Fixme: We enable verbose mode here because there is currently no
+     way to do this when starting g13-syshelp.  To fix that we should
+     add a g13-syshelp.conf file in /etc/gnupg.  */
+  opt.verbose = 1;
 
   /* First check whether we have a debug option on the commandline.  */
   orig_argc = argc;
diff --git a/g13/g13-syshelp.h b/g13/g13-syshelp.h
index 5a2055eb1..0503079cd 100644
--- a/g13/g13-syshelp.h
+++ b/g13/g13-syshelp.h
@@ -21,7 +21,7 @@
 #define G13_SYSHELP_H
 
 #include "g13-common.h"
-
+#include "g13tuple.h"
 
 struct tab_item_s;
 typedef struct tab_item_s *tab_item_t;
@@ -83,6 +83,8 @@ gpg_error_t sh_is_empty_partition (const char *name);
 /*-- sh-dmcrypt.c --*/
 gpg_error_t sh_dmcrypt_create_container (ctrl_t ctrl, const char *devname,
                                          estream_t devfp);
+gpg_error_t sh_dmcrypt_mount_container (ctrl_t ctrl, const char *devname,
+                                        tupledesc_t keyblob);
 
 
 #endif /*G13_SYSHELP_H*/
diff --git a/g13/g13.c b/g13/g13.c
index d9d40982a..b8a2dda6c 100644
--- a/g13/g13.c
+++ b/g13/g13.c
@@ -459,7 +459,7 @@ main ( int argc, char **argv)
           if (default_config)
             {
               if (parse_debug)
-                log_info (_("NOTE: no default option file '%s'\n"), configname);
+                log_info (_("Note: no default option file '%s'\n"), configname);
             }
           else
             {
@@ -625,6 +625,8 @@ main ( int argc, char **argv)
   /* Now that we have the options parsed we need to update the default
      control structure.  */
   g13_init_default_ctrl (&ctrl);
+  ctrl.recipients = recipients;
+  recipients = NULL;
 
   if (nogreeting)
     greeting = 0;
@@ -646,7 +648,7 @@ main ( int argc, char **argv)
 
       for (i=0; i < argc; i++)
         if (argv[i][0] == '-' && argv[i][1] == '-')
-          log_info (_("NOTE: '%s' is not considered an option\n"), argv[i]);
+          log_info (_("Note: '%s' is not considered an option\n"), argv[i]);
     }
 
 
@@ -698,7 +700,7 @@ main ( int argc, char **argv)
       strlist_t sl;
       int failed = 0;
 
-      for (sl = recipients; sl; sl = sl->next)
+      for (sl = ctrl->recipients; sl; sl = sl->next)
         if (check_encryption_key ())
           failed = 1;
       if (failed)
@@ -738,7 +740,7 @@ main ( int argc, char **argv)
           log_error ("server exited with error: %s <%s>\n",
                      gpg_strerror (err), gpg_strsource (err));
         else
-          shutdown_pending++;
+          g13_request_shutdown ();
       }
       break;
 
@@ -747,12 +749,12 @@ main ( int argc, char **argv)
         if (argc != 1)
           wrong_args ("--create filename");
         start_idle_task ();
-        err = g13_create_container (&ctrl, argv[0], recipients);
+        err = g13_create_container (&ctrl, argv[0]);
         if (err)
           log_error ("error creating a new container: %s <%s>\n",
                      gpg_strerror (err), gpg_strsource (err));
         else
-          shutdown_pending++;
+          g13_request_shutdown ();
       }
       break;
 
@@ -797,6 +799,16 @@ void
 g13_deinit_default_ctrl (ctrl_t ctrl)
 {
   call_syshelp_release (ctrl);
+  FREE_STRLIST (ctrl->recipients);
+}
+
+
+/* Request a shutdown.  This can be used when the process should
+ * finish instead of running the idle task.  */
+void
+g13_request_shutdown (void)
+{
+  shutdown_pending++;
 }
 
 
@@ -932,9 +944,11 @@ idle_task (void *dummy_arg)
 	}
 
       if (ret <= 0)
-	/* Interrupt or timeout.  Will be handled when calculating the
-	   next timeout.  */
-	continue;
+        {
+          /* Interrupt or timeout.  Will be handled when calculating the
+             next timeout.  */
+          continue;
+        }
 
       /* Here one would add processing of file descriptors.  */
     }
diff --git a/g13/g13.h b/g13/g13.h
index f6f88b96b..e69489069 100644
--- a/g13/g13.h
+++ b/g13/g13.h
@@ -47,11 +47,14 @@ struct server_control_s
   /* Type of the current container.  See the CONTTYPE_ constants.  */
   int conttype;
 
+  strlist_t recipients; /* List of recipients.  */
+
 };
 
 
 /*-- g13.c --*/
 void g13_init_default_ctrl (ctrl_t ctrl);
 void g13_deinit_default_ctrl (ctrl_t ctrl);
+void g13_request_shutdown (void);
 
 #endif /*G13_H*/
diff --git a/g13/g13tuple.c b/g13/g13tuple.c
index b3187fbfe..fc6644cb7 100644
--- a/g13/g13tuple.c
+++ b/g13/g13tuple.c
@@ -143,6 +143,18 @@ ref_tupledesc (tupledesc_t tupledesc)
 }
 
 
+/* Return a pointer to the memory used to store the tuples.  This is
+ * the data originally provided to create_tupledesc.  It is higly
+ * recommended that the callers uses ref_tupledesc before calling this
+ * function and unref_tupledesc when the return data will not anymore
+ * be used.  */
+const void *
+get_tupledesc_data (tupledesc_t tupledesc, size_t *r_datalen)
+{
+  *r_datalen = tupledesc->datalen;
+  return tupledesc->data;
+}
+
 /* Find the first tuple with tag TAG.  On success return a pointer to
    its value and store the length of the value at R_LENGTH.  If no
    tuple was found return NULL.  For use by next_tuple, the last
diff --git a/g13/g13tuple.h b/g13/g13tuple.h
index 948e3475e..c9dfb47b7 100644
--- a/g13/g13tuple.h
+++ b/g13/g13tuple.h
@@ -36,6 +36,9 @@ gpg_error_t create_tupledesc (tupledesc_t *r_tupledesc,
                               void *data, size_t datalen);
 void destroy_tupledesc (tupledesc_t tupledesc);
 tupledesc_t ref_tupledesc (tupledesc_t tupledesc);
+#define unref_tupledesc(a) destroy_tupledesc ((a))
+const void *get_tupledesc_data (tupledesc_t tupledesc, size_t *r_datalen);
+
 const void *find_tuple (tupledesc_t tupledesc,
                         unsigned int tag, size_t *r_length);
 gpg_error_t find_tuple_uint (tupledesc_t tupledesc, unsigned int tag,
diff --git a/g13/mount.c b/g13/mount.c
index bc54020eb..c5c8f22b4 100644
--- a/g13/mount.c
+++ b/g13/mount.c
@@ -70,11 +70,8 @@ parse_header (const char *filename,
     log_info ("WARNING: unknown meta information in '%s'\n", filename);
   if (packet[19])
     log_info ("WARNING: OS flag is not supported in '%s'\n", filename);
-  if (packet[24] != 1 || packet[25] != 0)
-    {
-      log_error ("meta data copies in '%s' are not supported\n", filename);
-      return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
-    }
+  if (packet[24] > 1 )
+    log_info ("Note: meta data copies in '%s' are ignored\n", filename);
 
   len = buf32_to_uint (packet+20);
 
@@ -216,6 +213,7 @@ g13_mount_container (ctrl_t ctrl, const char *filename, const char *mountpoint)
 {
   gpg_error_t err;
   dotlock_t lock;
+  int needs_syshelp;
   void *enckeyblob = NULL;
   size_t enckeybloblen;
   void *keyblob = NULL;
@@ -231,6 +229,12 @@ g13_mount_container (ctrl_t ctrl, const char *filename, const char *mountpoint)
   if (access (filename, R_OK))
     return gpg_error_from_syserror ();
 
+  /* Decide whether we need to use the g13-syshelp because we can't
+     use lock files for them.  This is most likely the case for device
+     files; thus we test for this.  FIXME: The correct solution would
+     be to call g13-syshelp to match the file against the g13tab.  */
+  needs_syshelp = !strncmp (filename, "/dev/", 5);
+
   if (!mountpoint)
     {
       mountpoint_buffer = xtrystrdup ("/tmp/g13-XXXXXX");
@@ -247,21 +251,25 @@ g13_mount_container (ctrl_t ctrl, const char *filename, const char *mountpoint)
       mountpoint = mountpoint_buffer;
     }
 
-  /* Try to take a lock.  */
-  lock = dotlock_create (filename, 0);
-  if (!lock)
-    {
-      xfree (mountpoint_buffer);
-      return gpg_error_from_syserror ();
-    }
-
-  if (dotlock_take (lock, 0))
-    {
-      err = gpg_error_from_syserror ();
-      goto leave;
-    }
+  err = 0;
+  if (needs_syshelp)
+    lock = NULL;
   else
-    err = 0;
+    {
+      /* Try to take a lock.  */
+      lock = dotlock_create (filename, 0);
+      if (!lock)
+        {
+          xfree (mountpoint_buffer);
+          return gpg_error_from_syserror ();
+        }
+
+      if (dotlock_take (lock, 0))
+        {
+          err = gpg_error_from_syserror ();
+          goto leave;
+        }
+    }
 
   /* Check again that the file exists.  */
   {
@@ -275,6 +283,8 @@ g13_mount_container (ctrl_t ctrl, const char *filename, const char *mountpoint)
   }
 
   /* Read the encrypted keyblob.  */
+  /* Fixme: Should we move this to syshelp for dm-crypt or do we
+     assume that the encrypted device is world readable?  */
   err = read_keyblob (filename, &enckeyblob, &enckeybloblen);
   if (err)
     goto leave;
@@ -311,8 +321,15 @@ g13_mount_container (ctrl_t ctrl, const char *filename, const char *mountpoint)
       goto leave;
     }
   err = be_mount_container (ctrl, conttype, filename, mountpoint, tuples, &rid);
-  if (!err)
+  if (err)
+    ;
+  else if (conttype == CONTTYPE_DM_CRYPT)
+    g13_request_shutdown ();
+  else
     {
+      /* Unless this is a DM-CRYPT mount we put it into our mounttable
+         so that we can manage the mounts ourselves.  For dm-crypt we
+         do not keep a process to monitor he mounts (for now).  */
       err = mountinfo_add_mount (filename, mountpoint, conttype, rid,
                                  !!mountpoint_buffer);
       /* Fixme: What shall we do if this fails?  Add a provisional
diff --git a/g13/server.c b/g13/server.c
index 07b74f8bf..2f4acf595 100644
--- a/g13/server.c
+++ b/g13/server.c
@@ -45,8 +45,6 @@ struct server_local_s
   assuan_context_t assuan_ctx;
 
   char *containername;  /* Malloced active containername.  */
-
-  strlist_t recipients; /* List of recipients.  */
 };
 
 
@@ -194,7 +192,7 @@ reset_notify (assuan_context_t ctx, char *line)
   xfree (ctrl->server_local->containername);
   ctrl->server_local->containername = NULL;
 
-  FREE_STRLIST (ctrl->server_local->recipients);
+  FREE_STRLIST (ctrl->recipients);
 
   assuan_close_input_fd (ctx);
   assuan_close_output_fd (ctx);
@@ -372,7 +370,7 @@ cmd_recipient (assuan_context_t ctx, char *line)
 
   line = skip_options (line);
 
-  if (!add_to_strlist_try (&ctrl->server_local->recipients, line))
+  if (!add_to_strlist_try (&ctrl->recipients, line))
     err = gpg_error_from_syserror ();
 
   return leave_cmd (ctx, err);
@@ -438,11 +436,11 @@ cmd_create (assuan_context_t ctx, char *line)
     }
 
   /* Create container.  */
-  err = g13_create_container (ctrl, line, ctrl->server_local->recipients);
+  err = g13_create_container (ctrl, line);
 
   if (!err)
     {
-      FREE_STRLIST (ctrl->server_local->recipients);
+      FREE_STRLIST (ctrl->recipients);
 
       /* Store the filename.  */
       ctrl->server_local->containername = xtrystrdup (line);
diff --git a/g13/sh-cmd.c b/g13/sh-cmd.c
index 8a3006cab..6ba4cd8c8 100644
--- a/g13/sh-cmd.c
+++ b/g13/sh-cmd.c
@@ -172,9 +172,15 @@ cmd_device (assuan_context_t ctx, char *line)
   tab_item_t ti;
   estream_t fp = NULL;
 
-  /* strcpy (line, "/dev/sdb1"); /\* FIXME *\/ */
   line = skip_options (line);
 
+/* # warning hardwired to /dev/sdb1 ! */
+/*   if (strcmp (line, "/dev/sdb1")) */
+/*     { */
+/*       err = gpg_error (GPG_ERR_ENOENT); */
+/*       goto leave; */
+/*     } */
+
   /* Always close an open device stream of this session. */
   xfree (ctrl->server_local->devicename);
   ctrl->server_local->devicename = NULL;
@@ -239,6 +245,81 @@ cmd_create (assuan_context_t ctx, char *line)
 {
   ctrl_t ctrl = assuan_get_pointer (ctx);
   gpg_error_t err = 0;
+  estream_t fp = NULL;
+
+  line = skip_options (line);
+  if (strcmp (line, "dm-crypt"))
+    {
+      err = set_error (GPG_ERR_INV_ARG, "Type must be \"dm-crypt\"");
+      goto leave;
+    }
+
+  if (!ctrl->server_local->devicename
+      || !ctrl->server_local->devicefp
+      || !ctrl->devti)
+    {
+      err = set_error (GPG_ERR_ENOENT, "No device has been set");
+      goto leave;
+    }
+
+  err = sh_is_empty_partition (ctrl->server_local->devicename);
+  if (err)
+    {
+      if (gpg_err_code (err) == GPG_ERR_FALSE)
+        err = gpg_error (GPG_ERR_CONFLICT);
+      err = assuan_set_error (ctx, err, "Partition is not empty");
+      goto leave;
+    }
+
+  /* We need a writeable stream to create the container.  */
+  fp = es_fopen (ctrl->server_local->devicename, "r+b");
+  if (!fp)
+    {
+      err = gpg_error_from_syserror ();
+      log_error ("error opening '%s': %s\n",
+                 ctrl->server_local->devicename, gpg_strerror (err));
+      goto leave;
+    }
+  if (es_setvbuf (fp, NULL, _IONBF, 0))
+    {
+      err = gpg_error_from_syserror ();
+      log_error ("error setting '%s' to _IONBF: %s\n",
+                 ctrl->server_local->devicename, gpg_strerror (err));
+      goto leave;
+    }
+
+  err = sh_dmcrypt_create_container (ctrl,
+                                     ctrl->server_local->devicename,
+                                     fp);
+  if (es_fclose (fp))
+    {
+      gpg_error_t err2 = gpg_error_from_syserror ();
+      log_error ("error closing '%s': %s\n",
+                 ctrl->server_local->devicename, gpg_strerror (err2));
+      if (!err)
+        err = err2;
+    }
+  fp = NULL;
+
+ leave:
+  es_fclose (fp);
+  return leave_cmd (ctx, err);
+}
+
+
+static const char hlp_mount[] =
+  "MOUNT <type>\n"
+  "\n"
+  "Mount an encrypted partition on the current device.\n"
+  "<type> must be \"dm-crypt\" for now.";
+static gpg_error_t
+cmd_mount (assuan_context_t ctx, char *line)
+{
+  ctrl_t ctrl = assuan_get_pointer (ctx);
+  gpg_error_t err = 0;
+  unsigned char *keyblob = NULL;
+  size_t keybloblen;
+  tupledesc_t tuples = NULL;
 
   line = skip_options (line);
 
@@ -257,25 +338,47 @@ cmd_create (assuan_context_t ctx, char *line)
     }
 
   err = sh_is_empty_partition (ctrl->server_local->devicename);
+  if (!err)
+    {
+      err = gpg_error (GPG_ERR_ENODEV);
+      assuan_set_error (ctx, err, "Partition is empty");
+      goto leave;
+    }
+  err = 0;
+
+  /* We expect that the client already decrypted the keyblob.
+   * Eventually we should move reading of the keyblob to here and ask
+   * the client to decrypt it.  */
+  assuan_begin_confidential (ctx);
+  err = assuan_inquire (ctx, "KEYBLOB",
+                        &keyblob, &keybloblen, 4 * 1024);
+  assuan_end_confidential (ctx);
   if (err)
     {
-      err = assuan_set_error (ctx, err, "Partition is not empty");
+      log_error (_("assuan_inquire failed: %s\n"), gpg_strerror (err));
+      goto leave;
+    }
+  err = create_tupledesc (&tuples, keyblob, keybloblen);
+  if (!err)
+    keyblob = NULL;
+  else
+    {
+      if (gpg_err_code (err) == GPG_ERR_NOT_SUPPORTED)
+        log_error ("unknown keyblob version received\n");
       goto leave;
     }
 
-  err = sh_dmcrypt_create_container (ctrl,
-                                     ctrl->server_local->devicename,
-                                     ctrl->server_local->devicefp);
-
-
-
+  err = sh_dmcrypt_mount_container (ctrl,
+                                    ctrl->server_local->devicename,
+                                    tuples);
 
  leave:
+  xfree (tuples);
+  destroy_tupledesc (tuples);
   return leave_cmd (ctx, err);
 }
 
 
-
 static const char hlp_getinfo[] =
   "GETINFO <what>\n"
   "\n"
@@ -372,6 +475,7 @@ register_commands (assuan_context_t ctx, int fail_all)
   } table[] =  {
     { "DEVICE",        cmd_device, hlp_device },
     { "CREATE",        cmd_create, hlp_create },
+    { "MOUNT",         cmd_mount,  hlp_mount  },
     { "INPUT",         NULL },
     { "OUTPUT",        NULL },
     { "GETINFO",       cmd_getinfo, hlp_getinfo },
diff --git a/g13/sh-dmcrypt.c b/g13/sh-dmcrypt.c
index 20eea2350..f0693b1e9 100644
--- a/g13/sh-dmcrypt.c
+++ b/g13/sh-dmcrypt.c
@@ -45,7 +45,7 @@
 
 /* The length of the crypto setup area in sectors.  16 KiB is a nice
    multiple of a modern block size and should be sufficient for all
-   kind of extra public key encryption packet.  */
+   kind of extra public key encryption packets.  */
 #define SETUP_AREA_SECTORS 32  /* 16 KiB */
 
 /* The number of header block copies stored at the begin and end of
@@ -208,11 +208,14 @@ mk_setup_area_prefix (size_t *r_length)
 }
 
 
+/* Create a new g13 styloe DM-Crypt container on devoce DEVNAME.  */
 gpg_error_t
 sh_dmcrypt_create_container (ctrl_t ctrl, const char *devname, estream_t devfp)
 {
   gpg_error_t err;
   char *header_space;
+  size_t header_space_size, header_space_used;
+  size_t paddinglen;
   char *targetname = NULL;
   size_t nread;
   char *p;
@@ -226,11 +229,14 @@ sh_dmcrypt_create_container (ctrl_t ctrl, const char *devname, estream_t devfp)
   size_t keyblob_len;
   size_t n;
   const char *s;
+  unsigned char *packet;
+  int copy;
 
   if (!ctrl->devti)
     return gpg_error (GPG_ERR_INV_ARG);
 
-  header_space = xtrymalloc (HEADER_SECTORS * SECTOR_SIZE);
+  header_space_size = SETUP_AREA_SECTORS * SECTOR_SIZE;
+  header_space = xtrymalloc (header_space_size);
   if (!header_space)
     return gpg_error_from_syserror ();
 
@@ -248,7 +254,7 @@ sh_dmcrypt_create_container (ctrl_t ctrl, const char *devname, estream_t devfp)
     append_tuple (&keyblob, KEYBLOB_TAG_CREATED, tbuf, strlen (tbuf));
   }
 
-  /* Rewind out stream.  */
+  /* Rewind device stream.  */
   if (es_fseeko (devfp, 0, SEEK_SET))
     {
       err = gpg_error_from_syserror ();
@@ -259,9 +265,9 @@ sh_dmcrypt_create_container (ctrl_t ctrl, const char *devname, estream_t devfp)
   es_clearerr (devfp);
 
   /* Extra check that the device is empty.  */
-  if (es_read (devfp, header_space, HEADER_SECTORS * SECTOR_SIZE, &nread))
+  if (es_read (devfp, header_space, header_space_size, &nread))
     err = gpg_error_from_syserror ();
-  else if (nread != HEADER_SECTORS * SECTOR_SIZE)
+  else if (nread != header_space_size)
     err = gpg_error (GPG_ERR_TOO_SHORT);
   else
     err = 0;
@@ -302,7 +308,10 @@ sh_dmcrypt_create_container (ctrl_t ctrl, const char *devname, estream_t devfp)
       err = gpg_error (GPG_ERR_TOO_SHORT);
       goto leave;
     }
+  append_tuple_uint (&keyblob, KEYBLOB_TAG_CONT_NSEC, nblocks);
   nblocks -= HEADER_SECTORS + FOOTER_SECTORS;
+  append_tuple_uint (&keyblob, KEYBLOB_TAG_ENC_NSEC, nblocks);
+  append_tuple_uint (&keyblob, KEYBLOB_TAG_ENC_OFF, HEADER_SECTORS);
 
   /* Device mapper needs a name for the device: Take it from the label
      or use "0".  */
@@ -349,6 +358,9 @@ sh_dmcrypt_create_container (ctrl_t ctrl, const char *devname, estream_t devfp)
       goto leave;
     }
   append_tuple (&keyblob, KEYBLOB_TAG_HDRCOPY, p, n);
+  assert (n < header_space_size);
+  memcpy (header_space, p, n);
+  header_space_used = n;
 
   /* Turn the keyblob into a buffer and callback to encrypt it.  */
   keyblob_buf = get_membuf (&keyblob, &keyblob_len);
@@ -363,29 +375,133 @@ sh_dmcrypt_create_container (ctrl_t ctrl, const char *devname, estream_t devfp)
       log_error ("encrypting the keyblob failed: %s\n", gpg_strerror (err));
       goto leave;
     }
+  log_debug ("plain setuparea=%p %zu bytes\n", keyblob_buf, keyblob_len);
   wipememory (keyblob_buf, keyblob_len);
   xfree (keyblob_buf);
   keyblob_buf = NULL;
 
-  /* Create the container.  */
-  /* { */
-  /*   const char *argv[3]; */
+  log_debug ("encry setuparea=%p %zu bytes\n", p, n);
+  if (n >= header_space_size || (header_space_used + n) >= header_space_size)
+    {
+      err = gpg_error (GPG_ERR_TOO_LARGE);
+      log_error ("setup area would overflow: %s\n", gpg_strerror (err));
+      goto leave;
+    }
+  memcpy (header_space + header_space_used, p, n);
+  header_space_used += n;
 
-  /*   argv[0] = "create"; */
-  /*   argv[1] = targetname; */
-  /*   argv[2] = NULL; */
-  /*   err = sh_exec_tool ("/sbin/dmsetup", argv, table, &result, NULL); */
-  /* } */
-  /* if (err) */
-  /*   { */
-  /*     log_error ("error running dmsetup for '%s': %s\n", */
-  /*                devname, gpg_strerror (err)); */
-  /*     goto leave; */
-  /*   } */
-  /* log_debug ("dmsetup result: %s\n", result); */
+  /* Write the padding.  */
+  packet = header_space + header_space_used;
+  paddinglen = header_space_size - header_space_used;
+  if (paddinglen < 16)
+    {
+      err = gpg_error (GPG_ERR_TOO_LARGE);
+      log_error ("setup area too short for padding: %s\n", gpg_strerror (err));
+      goto leave;
+    }
+  packet[0] = (0xc0|61); /* CTB for Private packet type 0x61.  */
+  packet[1] = 0xff;      /* 5 byte length packet, value 20.  */
+  packet[2] = (paddinglen-6) >> 24;
+  packet[3] = (paddinglen-6) >> 16;
+  packet[4] = (paddinglen-6) >> 8;
+  packet[5] = (paddinglen-6);
+  packet += 6;
+  paddinglen -= 6;
+  header_space_used += 6;
+  for ( ;paddinglen >= 10;
+        paddinglen -= 10, packet += 10, header_space_used += 10)
+    memcpy (packet, "GnuPG/PAD", 10);
+  for ( ;paddinglen; paddinglen--, packet++, header_space_used++)
+    *packet = 0;
+
+  if (header_space_used != header_space_size)
+    BUG ();
+
+  /* Create the container.  */
+  {
+    const char *argv[3];
+
+    argv[0] = "create";
+    argv[1] = targetname;
+    argv[2] = NULL;
+    log_debug ("now running \"dmsetup create %s\"\n", targetname);
+    log_debug ("  with table='%s'\"\n", table);
+    err = gnupg_exec_tool ("/sbin/dmsetup", argv, table, &result, NULL);
+  }
+  if (err)
+    {
+      log_error ("error running dmsetup for '%s': %s\n",
+                 devname, gpg_strerror (err));
+      goto leave;
+    }
+  if (result && *result)
+    log_debug ("dmsetup result: %s\n", result);
 
   /* Write the setup area.  */
+  if (es_fseeko (devfp, 0, SEEK_SET))
+    {
+      err = gpg_error_from_syserror ();
+      log_error ("error seeking to begin of '%s': %s\n",
+                 devname, gpg_strerror (err));
+      goto leave;
+    }
+  es_clearerr (devfp);
 
+  for (copy = 0; copy < HEADER_SETUP_AREA_COPIES; copy++)
+    {
+      size_t nwritten;
+
+      if (es_write (devfp, header_space, header_space_size, &nwritten))
+        {
+          err = gpg_error_from_syserror ();
+          break;
+        }
+      else if (nwritten != header_space_size)
+        {
+          err = gpg_error (GPG_ERR_TOO_SHORT);
+          break;
+        }
+    }
+  if (err)
+    {
+      log_error ("error writing header space copy %d of '%s': %s\n",
+                 copy, devname, gpg_strerror (err));
+      goto leave;
+    }
+
+  if (es_fseeko (devfp,
+                 (- header_space_size * FOOTER_SETUP_AREA_COPIES), SEEK_END))
+    {
+      err = gpg_error_from_syserror ();
+      log_error ("error seeking to end of '%s': %s\n",
+                 devname, gpg_strerror (err));
+      goto leave;
+    }
+  es_clearerr (devfp);
+
+  for (copy = 0; copy < FOOTER_SETUP_AREA_COPIES; copy++)
+    {
+      size_t nwritten;
+
+      if (es_write (devfp, header_space, header_space_size, &nwritten))
+        {
+          err = gpg_error_from_syserror ();
+          break;
+        }
+      else if (nwritten != header_space_size)
+        {
+          err = gpg_error (GPG_ERR_TOO_SHORT);
+          break;
+        }
+    }
+  if (!err && es_fflush (devfp))
+    err = gpg_error_from_syserror ();
+  if (err)
+    {
+      log_error ("error writing footer space copy %d of '%s': %s\n",
+                 copy, devname, gpg_strerror (err));
+      goto leave;
+    }
 
  leave:
   wipememory (hexkey, sizeof hexkey);
@@ -405,3 +521,166 @@ sh_dmcrypt_create_container (ctrl_t ctrl, const char *devname, estream_t devfp)
   xfree (header_space);
   return err;
 }
+
+
+/* Mount a DM-Crypt congtainer on device DEVNAME taking keys and other
+ * meta data from KEYBLOB.  */
+gpg_error_t
+sh_dmcrypt_mount_container (ctrl_t ctrl, const char *devname,
+                            tupledesc_t keyblob)
+{
+  gpg_error_t err;
+  char *targetname = NULL;
+  char hexkey[16*2+1];
+  char *table = NULL;
+  unsigned long long nblocks, nblocks2;
+  char *result = NULL;
+  size_t n;
+  const char *s;
+  const char *algostr;
+  size_t algostrlen;
+
+  if (!ctrl->devti)
+    return gpg_error (GPG_ERR_INV_ARG);
+
+  /* Check that the device is not yet used by device mapper. */
+  err = check_blockdev (devname);
+  if (err)
+    goto leave;
+
+  /* Compute the number of blocks and compare them to the value
+     provided as meta data.  */
+  err = sh_blockdev_getsz (devname, &nblocks);
+  if (err)
+    {
+      log_error ("error getting size of '%s': %s\n",
+                 devname, gpg_strerror (err));
+      goto leave;
+    }
+  err = find_tuple_uint (keyblob, KEYBLOB_TAG_CONT_NSEC, &nblocks2);
+  if (err)
+    {
+      log_error ("error getting size from keyblob: %s\n", gpg_strerror (err));
+      goto leave;
+    }
+  if (nblocks != nblocks2)
+    {
+      log_error ("inconsistent size of container: expected==%llu got=%llu\n",
+                 nblocks2, nblocks);
+      err = gpg_error (GPG_ERR_INV_DATA);
+      goto leave;
+    }
+  if (nblocks <= HEADER_SECTORS + MIN_ENCRYPTED_SPACE + FOOTER_SECTORS)
+    {
+      log_error ("device '%s' is too small (min=%d blocks)\n",
+                 devname,
+                 HEADER_SECTORS + MIN_ENCRYPTED_SPACE + FOOTER_SECTORS);
+      err = gpg_error (GPG_ERR_TOO_SHORT);
+      goto leave;
+    }
+  nblocks -= HEADER_SECTORS + FOOTER_SECTORS;
+  err = find_tuple_uint (keyblob, KEYBLOB_TAG_ENC_NSEC, &nblocks2);
+  if (err)
+    {
+      log_error ("error getting enc size from keyblob: %s\n",
+                 gpg_strerror (err));
+      goto leave;
+    }
+  if (nblocks != nblocks2)
+    {
+      log_error ("inconsistent size of enc data: expected==%llu got=%llu\n",
+                 nblocks2, nblocks);
+      err = gpg_error (GPG_ERR_INV_DATA);
+      goto leave;
+    }
+  /* Check that the offset is consistent.  */
+  err = find_tuple_uint (keyblob, KEYBLOB_TAG_ENC_OFF, &nblocks2);
+  if (err)
+    {
+      log_error ("error getting enc offset from keyblob: %s\n",
+                 gpg_strerror (err));
+      goto leave;
+    }
+  if (nblocks2 != HEADER_SECTORS)
+    {
+      log_error ("inconsistent offset of enc data: expected==%llu got=%d\n",
+                 nblocks2, HEADER_SECTORS);
+      err = gpg_error (GPG_ERR_INV_DATA);
+      goto leave;
+    }
+
+  /* Device mapper needs a name for the device: Take it from the label
+     or use "0".  */
+  targetname = strconcat ("g13-", ctrl->client.uname, "-",
+                          ctrl->devti->label? ctrl->devti->label : "0",
+                          NULL);
+  if (!targetname)
+    {
+      err = gpg_error_from_syserror ();
+      goto leave;
+    }
+
+  /* Get the algorithm string.  */
+  algostr = find_tuple (keyblob, KEYBLOB_TAG_ALGOSTR, &algostrlen);
+  if (!algostr || algostrlen > 100)
+    {
+      log_error ("algo string not found in keyblob or too long\n");
+      err = gpg_error (GPG_ERR_INV_DATA);
+      goto leave;
+    }
+
+  /* Get the key.  */
+  s = find_tuple (keyblob, KEYBLOB_TAG_ENCKEY, &n);
+  if (!s || n != 16)
+    {
+      if (!s)
+        log_error ("no key found in keyblob\n");
+      else
+        log_error ("unexpected size of key (%zu)\n", n);
+      err = gpg_error (GPG_ERR_INV_KEYLEN);
+      goto leave;
+    }
+  bin2hex (s, 16, hexkey);
+
+  /* Build dmcrypt table. */
+  table = es_bsprintf ("0 %llu crypt %.*s %s 0 %s %d",
+                       nblocks, (int)algostrlen, algostr,
+                       hexkey, devname, HEADER_SECTORS);
+  wipememory (hexkey, sizeof hexkey);
+  if (!table)
+    {
+      err = gpg_error_from_syserror ();
+      goto leave;
+    }
+
+  /* Load the table.  */
+  {
+    const char *argv[3];
+
+    argv[0] = "create";
+    argv[1] = targetname;
+    argv[2] = NULL;
+    log_debug ("now running \"dmsetup create %s\"\n", targetname);
+    err = gnupg_exec_tool ("/sbin/dmsetup", argv, table, &result, NULL);
+  }
+  if (err)
+    {
+      log_error ("error running dmsetup for '%s': %s\n",
+                 devname, gpg_strerror (err));
+      goto leave;
+    }
+  if (result && *result)
+    log_debug ("dmsetup result: %s\n", result);
+
+
+ leave:
+  wipememory (hexkey, sizeof hexkey);
+  if (table)
+    {
+      wipememory (table, strlen (table));
+      xfree (table);
+    }
+  xfree (targetname);
+  xfree (result);
+  return err;
+}