diff --git a/README.md b/README.md
index e8a3839..975cdd3 100644
--- a/README.md
+++ b/README.md
@@ -6,75 +6,40 @@
 * deleting a drive securely via overwriting
 
 ## Screenshot 
-![alt text](https://git.mosad.xyz/localhorst/reHDD/raw/commit/95828afcc2e417b9cb64a4add98ae9c3c7628e84/doc/screenshot.png "Screenshot")
+![alt text](https://git.mosad.xyz/localhorst/reHDD/raw/commit/42bc26eac95429e20c0f0d59f684dfec0d600e75/doc/screenshot.png "Screenshot")
 
 ## Debian Build Notes
 
-* apt-get install ncurses-dev git make g++ 
-* clone repo in /root/
-* make release
+* `apt-get install ncurses-dev git make g++`
+* `make release`
 
 ## Create Standalone with Debian 11
 
 Instructions how to create a standalone machine that boots directly to reHDD. This is aimed for production use, like several drives a day shredding.
+* Start reHDD after boot without login (as a tty1 shell)
+* Start dmesg after boot without login (as a tty2 shell)
+* Start htop after boot without login (as a tty3 shell)
+* Upload reHDD log every 12h if wanted
 
 ### Software requirements
 
-* apt-get install hwinfo smartmontools curl
+* `apt-get install hwinfo smartmontools curl`
 
-### Start reHDD after boot without login (as a tty shell)
+### Installation
 
-mkdir /lib/systemd/system/getty@tty1.service.d/
+clone this repo into /root/
 
-nano /lib/systemd/system/getty@tty1.service.d/override.conf
+`cd /root/reHDD/`
 
-```
-[Service]
-WorkingDirectory=/root/reHDD
-ExecStart=
-ExecStart=-/root/reHDD/reHDD
-StandardInput=tty
-StandardOutput=tty
-Restart=always
-RestartSec=1
-UtmpIdentifier=tty1
-TTYPath=/dev/tty1
-TTYReset=yes
-TTYVHangup=yes
-TTYVTDisallocate=yes
-SendSIGHUP=yes
+`make release`
 
-```
+`bash scripts/install_reHDD.bash`
 
-systemctl daemon-reload
+If you want to upload the logs, edit `scripts/reHDDLogUploader.bash` with your nextcloud token
 
-nano /etc/systemd/system/reHDDSettings.service 
-```
-[Service]
-Type=oneshot
-RemainAfterExit=yes
-ExecStart=/usr/bin/bash /root/reHDDSettings.sh
-
-[Install]
-WantedBy=multi-user.target
-```
-
-nano /root/reHDDSettings.sh
-```
-#!/bin/bash
-dmesg -n 1 #disable overlay if a drive is attached/detached
-# remove comment for the following to activate log telemetie
-# curl -k -T /root/reHDD/reHDD.log -u "fgggfffgfgfgfg:" -H 'X-Requested-With: XMLHttpRequest' https://schuttercloud.com/public.php/webdav/`echo $(date '+%Y-%m-%d_%H-%M')`_reHDD.log
-rm -f /root/reHDD/reHDD.log
-```
-chmod +x reHDDSettings.sh
-
-
-Make sure the binary reHDD is in /root/reHDD/
-
-Add your system drive in /root/reHDD/ignoreDrives.conf like:
+Add your system drive in `/root/reHDD/ignoreDrives.conf` like:
 ```e102f49d```
-Get the first 8 Bytes from your UUID via blkid /dev/sdX
+Get the first 8 Bytes from your UUID via `blkid /dev/sdX`
 
-systemctl enable reHDDSettings.service
+`reboot`
 
diff --git a/astyle.sh b/astyle.sh
index dee3705..604ad39 100644
--- a/astyle.sh
+++ b/astyle.sh
@@ -5,20 +5,13 @@ echo starting astyle for $PWD
 astyle --style=gnu src/*.cpp
 rm -f src/*.orig
 
-astyle --style=gnu src/shred/*.cpp
-rm -f src/shred/*.orig
-
 astyle --style=gnu src/logger/*.cpp
 rm -f src/logger/*.orig
 
-
 astyle --style=gnu include/*.h
-rm -f include//*.orig
+rm -f include/*.orig
 
-astyle --style=gnu include//shred/*.h
-rm -f include//shred/*.orig
-
-astyle --style=gnu include//logger/*.h
+astyle --style=gnu include/logger/*.h
 rm -f include//logger/*.orig
 
 echo finished astyle for $PWD
diff --git a/doc/screenshot.png b/doc/screenshot.png
index 7606712..0fd095e 100644
Binary files a/doc/screenshot.png and b/doc/screenshot.png differ
diff --git a/ignoreDrives.conf b/ignoreDrives.conf
index f08bed0..06e17c4 100644
--- a/ignoreDrives.conf
+++ b/ignoreDrives.conf
@@ -1 +1,2 @@
 4673974d
+2cb3dea4
diff --git a/include/drive.h b/include/drive.h
index 11419eb..5427eeb 100644
--- a/include/drive.h
+++ b/include/drive.h
@@ -25,6 +25,7 @@ public:
     bool bWasShredded = false;
     bool bWasDeleteted = false;
     bool bIsOffline = false;
+    uint32_t u32DriveChecksumAferShredding = 0U;
 
 private:
     string sPath;
diff --git a/include/reHDD.h b/include/reHDD.h
index b213dc9..08d2ac4 100644
--- a/include/reHDD.h
+++ b/include/reHDD.h
@@ -8,12 +8,12 @@
 #ifndef REHDD_H_
 #define REHDD_H_
 
-#define REHDD_VERSION "bV0.2.1"
+#define REHDD_VERSION "bV0.2.2"
 
 // Drive handling Settings
 #define WORSE_HOURS   19200 //mark drive if at this limit or beyond
 #define WORSE_POWERUP 10000  //mark drive if at this limit or beyond
-#define SHRED_ITERATIONS 3
+#define SHRED_ITERATIONS 3U
 #define FROZEN_TIMEOUT 10 //After this timeout (minutes) the drive will be marked as frozen
 
 // Logger Settings
@@ -23,14 +23,15 @@
 #define SOFTWARE_VERSION  "alpha"
 #define HARDWARE_VERSION  "generic"
 
-#define LOG_LEVEL_HIGH  //log everything, like drive scann thread
+//#define LOG_LEVEL_HIGH  //log everything, like drive scan thread
 #ifndef LOG_LEVEL_HIGH
 #define LOG_LEVEL_LOW   //log only user actions and tasks 
 #endif
 
 // Logic
-#define DRYRUN //don´t touch the drives
+//#define DRYRUN //don´t touch the drives
 #define FROZEN_ALERT //show alert if drive is frozen
+#define ZERO_CHECK_ALERT //check drive after shred if all bytes are zero, show alert if this fails
 
 //IPC pipes
 #define READ 0
@@ -58,7 +59,7 @@ using namespace std;
 
 #include "drive.h"
 #include "smart.h"
-#include "shred/shred.h"
+#include "shred.h"
 #include "delete.h"
 #include "tui.h"
 #include "logger/logger.h"
diff --git a/include/shred.h b/include/shred.h
new file mode 100644
index 0000000..a89457e
--- /dev/null
+++ b/include/shred.h
@@ -0,0 +1,56 @@
+/**
+ * @file    shred.h
+ * @brief   shred drive
+ * @author  hendrik schutter
+ * @date    03.05.2020
+ */
+
+#ifndef SHRED_H_
+#define SHRED_H_
+
+#include "reHDD.h"
+
+#include <iostream>
+#include <fstream>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+
+#define CHUNK_SIZE 1024*1024*2 //amount of bytes that are overwritten at once --> 2MB
+#define CHUNK_DIMENSION 100U //amount of chunks are read at once from random source
+
+//#define DEMO_DRIVE_SIZE 1024*1024*256L // 256MB
+//#define DEMO_DRIVE_SIZE 1024*1024*1024L // 1GB
+//#define DEMO_DRIVE_SIZE 1024*1024*1024*10L // 10GB
+
+typedef int fileDescriptor;
+
+class Shred
+{
+protected:
+
+public:
+
+    Shred();
+    ~Shred();
+    int shredDrive(Drive* drive, int* ipSignalFd);
+
+private:
+    fileDescriptor randomSrcFileDiscr;
+    fileDescriptor driveFileDiscr;
+    unsigned char caChunk[CHUNK_DIMENSION][CHUNK_SIZE];
+    unsigned long ulDriveByteSize;
+    unsigned long ulDriveByteOverallCount = 0; //all bytes shredded in all iterations + checking -> used for progress calculation
+    double d32Percent = 0.0;
+    double d32TmpPercent = 0.0;
+
+    inline double calcProgress();
+    int iRewindDrive(fileDescriptor file);
+    unsigned long getDriveSizeInBytes(fileDescriptor file);
+    unsigned int uiCalcChecksum(fileDescriptor file, Drive* drive, int* ipSignalFd);
+    void cleanup();
+
+};
+
+#endif  // SHRED_H_
diff --git a/include/shred/machdefs.h b/include/shred/machdefs.h
deleted file mode 100644
index a99d0eb..0000000
--- a/include/shred/machdefs.h
+++ /dev/null
@@ -1,19 +0,0 @@
-#ifndef _MACHINE_DEFINITIONS_HEADER
-#define _MACHINE_DEFINITIONS_HEADER
-
-#include <stdint.h>
-#include <limits.h>
-
-#undef MACHINE_16BIT
-#undef MACHINE_32BIT
-#undef MACHINE_64BIT
-
-#if UINTPTR_MAX == UINT32_MAX
-#define MACHINE_32BIT
-#elif UINTPTR_MAX == UINT64_MAX
-#define MACHINE_64BIT
-#elif UINTPTR_MAX == UINT16_MAX
-#define MACHINE_16BIT
-#endif
-
-#endif
diff --git a/include/shred/shred.h b/include/shred/shred.h
deleted file mode 100644
index dcefdfc..0000000
--- a/include/shred/shred.h
+++ /dev/null
@@ -1,98 +0,0 @@
-/**
- * @file    shred.h
- * @brief   shred drive
- * @author  hendrik schutter
- * @date    03.05.2020
- */
-
-#ifndef SHRED_H_
-#define SHRED_H_
-
-#include "../reHDD.h"
-
-#include <stdlib.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <string.h>
-#include <stdio.h>
-#include <errno.h>
-#include <limits.h>
-#include <libgen.h>
-
-
-#include "tfdef.h"
-#include "tfcore.h"
-//#include "tfe.h"
-
-#ifndef _DEFAULT_SOURCE
-#define _DEFAULT_SOURCE
-#endif
-#ifndef _BSD_SOURCE
-#define _BSD_SOURCE
-#endif
-#ifndef _XOPEN_SOURCE
-#define _XOPEN_SOURCE 700
-#endif
-#ifndef _LARGEFILE64_SOURCE
-#define _LARGEFILE64_SOURCE
-#endif
-#ifndef _FILE_OFFSET_BITS
-#define _FILE_OFFSET_BITS 64
-#endif
-
-#ifndef _TFNG_STREAM_CIPHER_DEFS
-#define _TFNG_STREAM_CIPHER_DEFS
-#endif
-
-#define PROCESS_BLOCKP(x,k1,k2,k3,k4,k5,k6)						\
-	do {										\
-		KE_MIX(Y, X, k1 + k2, k3, TFS_KS01);					\
-		KE_MIX(T, Z, k4 + x, k5 + k6, TFS_KS02);				\
-											\
-		BE_MIX(X, T, TFS_BS01); BE_MIX(Z, Y, TFS_BS02);				\
-		BE_MIX(X, Y, TFS_BS03); BE_MIX(Z, T, TFS_BS04);				\
-		BE_MIX(X, T, TFS_BS05); BE_MIX(Z, Y, TFS_BS06);				\
-	} while (0)
-
-#define PROCESS_BLOCKN(x,k1,k2,k3,k4,k5,k6)						\
-	do {										\
-		KE_MIX(Y, X, k1 + k2, k3, TFS_KS03);					\
-		KE_MIX(T, Z, k4 + x, k5 + k6, TFS_KS04);				\
-											\
-		BE_MIX(X, T, TFS_BS07); BE_MIX(Z, Y, TFS_BS08);				\
-		BE_MIX(X, Y, TFS_BS09); BE_MIX(Z, T, TFS_BS10);				\
-		BE_MIX(X, T, TFS_BS11); BE_MIX(Z, Y, TFS_BS12);				\
-	} while (0)
-
-
-#define NOSIZE ((size_t)-1)
-
-#define XRET(x) if (!xret && xret < x) xret = x
-
-class Shred
-{
-protected:
-
-public:
-
-    Shred();
-    ~Shred();
-    void shredDrive(Drive* drive, int* ipSignalFd);
-
-private:
-
-    unsigned long blockcount = 0UL;
-    long blockcount_max;
-    double d32Percent;
-
-    inline double calcProgress();
-    inline void tfnge_init_iv(struct tfnge_stream *tfe, const void *key, const void *iv);
-    inline void tfnge_init(struct tfnge_stream *tfe, const void *key);
-    inline void tfng_encrypt_rawblk(TFNG_UNIT_TYPE *O, const TFNG_UNIT_TYPE *I, const TFNG_UNIT_TYPE *K);
-    inline void tfnge_emit(void *dst, size_t szdst, struct tfnge_stream *tfe);
-
-};
-
-#endif  // SHRED_H_
diff --git a/include/shred/tfcore.h b/include/shred/tfcore.h
deleted file mode 100644
index 2d9d53e..0000000
--- a/include/shred/tfcore.h
+++ /dev/null
@@ -1,51 +0,0 @@
-#ifndef _THREEFISH_NOISE_GENERATOR_CIPHER_CORE_HEADER
-#define _THREEFISH_NOISE_GENERATOR_CIPHER_CORE_HEADER
-
-#ifndef _THREEFISH_NOISE_GENERATOR_CIPHER_DEFINITIONS_HEADER
-#error Threefish definitions header is required! Include tfdef.h first.
-#endif
-
-#define ROL(x, s, max) ((x << s) | (x >> (-s & (max-1))))
-#define ROR(x, s, max) ((x >> s) | (x << (-s & (max-1))))
-
-#define KE_MIX(x, y, k1, k2, sl)				\
-	do {							\
-		x += k1;					\
-		y += x;						\
-		y += k2;					\
-		x = ROL(x, sl, TFNG_UNIT_BITS);			\
-		x ^= y;						\
-	} while (0)
-
-#define BE_MIX(x, y, sl)					\
-	do {							\
-		x += y;						\
-		y = ROL(y, sl, TFNG_UNIT_BITS);			\
-		y ^= x;						\
-	} while (0)
-
-#define KD_MIX(x, y, k1, k2, sr)				\
-	do {							\
-		x ^= y;						\
-		x = ROR(x, sr, TFNG_UNIT_BITS);			\
-		y -= x;						\
-		y -= k2;					\
-		x -= k1;					\
-	} while (0)
-
-#define BD_MIX(x, y, sr)					\
-	do {							\
-		y ^= x;						\
-		y = ROR(y, sr, TFNG_UNIT_BITS);			\
-		x -= y;						\
-	} while (0)
-
-enum tfng_rotations
-{
-    TFS_KS01 =  7, TFS_KS02 = 25, TFS_KS03 = 19, TFS_KS04 =  7,
-    TFS_BS01 =  5, TFS_BS02 = 27, TFS_BS03 = 26, TFS_BS04 =  6,
-    TFS_BS05 = 14, TFS_BS06 = 11, TFS_BS07 = 24, TFS_BS08 = 18,
-    TFS_BS09 =  9, TFS_BS10 = 24, TFS_BS11 =  6, TFS_BS12 =  7,
-};
-
-#endif
diff --git a/include/shred/tfdef.h b/include/shred/tfdef.h
deleted file mode 100644
index ea0bd0b..0000000
--- a/include/shred/tfdef.h
+++ /dev/null
@@ -1,39 +0,0 @@
-#ifndef _THREEFISH_NOISE_GENERATOR_CIPHER_DEFINITIONS_HEADER
-#define _THREEFISH_NOISE_GENERATOR_CIPHER_DEFINITIONS_HEADER
-
-#ifndef _DEFAULT_SOURCE
-#define _DEFAULT_SOURCE
-#endif
-
-#ifndef _BSD_SOURCE
-#define _BSD_SOURCE
-#endif
-
-#include <stddef.h>
-#include <stdint.h>
-#include "machdefs.h"
-
-#if defined(MACHINE_64BIT)
-#define TFNG_UNIT_TYPE uint64_t
-#define TFNG_NR_BLOCK_BITS 256
-#define TFNG_NR_KEY_BITS 512
-#else
-#define TFNG_UNIT_TYPE uint32_t
-#define TFNG_NR_BLOCK_BITS 128
-#define TFNG_NR_KEY_BITS 256
-#endif
-
-#define TFNG_NR_BLOCK_UNITS 4
-#define TFNG_NR_KEY_UNITS 8
-
-#define TFNG_BYTE_TYPE uint8_t
-#define TFNG_SIZE_UNIT (sizeof(TFNG_UNIT_TYPE))
-#define TFNG_BLOCK_SIZE (TFNG_SIZE_UNIT * TFNG_NR_BLOCK_UNITS)
-#define TFNG_KEY_SIZE (TFNG_SIZE_UNIT * TFNG_NR_KEY_UNITS)
-
-#define TFNG_TO_BITS(x) ((x) * 8)
-#define TFNG_FROM_BITS(x) ((x) / 8)
-#define TFNG_MAX_BITS TFNG_NR_BLOCK_BITS
-#define TFNG_UNIT_BITS (TFNG_SIZE_UNIT * 8)
-
-#endif
diff --git a/include/tui.h b/include/tui.h
index 58312ce..c18e64d 100644
--- a/include/tui.h
+++ b/include/tui.h
@@ -62,6 +62,7 @@ private:
     static WINDOW *createDialog(int iXSize, int iYSize, int iXStart, int iYStart, string selectedTask, string optionA, string optionB);
     static WINDOW* createFrozenWarning(int iXSize, int iYSize, int iXStart, int iYStart, string sPath, string sModelFamily, string sModelName, string sSerial, string sProgress);
     static WINDOW* createSmartWarning(int iXSize, int iYSize, int iXStart, int iYStart, string sPath, uint32_t u32PowerOnHours, uint32_t u32PowerCycles,  uint32_t u32ErrorCount);
+    static WINDOW* createZeroChecksumWarning(int iXSize, int iYSize, int iXStart, int iYStart, string sPath, string sModelFamily, string sModelName, string sSerial, uint32_t u32Checksum);
 
     void displaySelectedDrive(Drive drive, int stdscrX, int stdscrY);
     string formatTimeDuration(time_t u32Duration);
diff --git a/scripts/getty@tty1.service.d_override.conf b/scripts/getty@tty1.service.d_override.conf
new file mode 100644
index 0000000..4544b4e
--- /dev/null
+++ b/scripts/getty@tty1.service.d_override.conf
@@ -0,0 +1,17 @@
+[Unit]
+Description=reHDD on tty1
+
+[Service]
+WorkingDirectory=/root/reHDD/
+ExecStart=
+ExecStart=-/root/reHDD/reHDD
+StandardInput=tty
+StandardOutput=tty
+Restart=always
+RestartSec=1
+UtmpIdentifier=tty1
+TTYPath=/dev/tty1
+TTYReset=yes
+TTYVHangup=yes
+TTYVTDisallocate=yes
+SendSIGHUP=yes
diff --git a/scripts/getty@tty2.service.d_override.conf b/scripts/getty@tty2.service.d_override.conf
new file mode 100644
index 0000000..4dc5b66
--- /dev/null
+++ b/scripts/getty@tty2.service.d_override.conf
@@ -0,0 +1,17 @@
+[Unit]
+Description=dmesg on tty2
+
+[Service]
+WorkingDirectory=/usr/bin/
+ExecStart=
+ExecStart=-/usr/bin/dmesg -wH
+StandardInput=tty
+StandardOutput=tty
+Restart=always
+RestartSec=1
+UtmpIdentifier=tty2
+TTYPath=/dev/tty2
+TTYReset=yes
+TTYVHangup=yes
+TTYVTDisallocate=yes
+SendSIGHUP=yes
diff --git a/scripts/getty@tty3.service.d_override.conf b/scripts/getty@tty3.service.d_override.conf
new file mode 100644
index 0000000..4b96c75
--- /dev/null
+++ b/scripts/getty@tty3.service.d_override.conf
@@ -0,0 +1,17 @@
+[Unit]
+Description=htop on tty3
+
+[Service]
+WorkingDirectory=/usr/bin/
+ExecStart=
+ExecStart=-/usr/bin/htop
+StandardInput=tty
+StandardOutput=tty
+Restart=always
+RestartSec=1
+UtmpIdentifier=tty3
+TTYPath=/dev/tty3
+TTYReset=yes
+TTYVHangup=yes
+TTYVTDisallocate=yes
+SendSIGHUP=yes
diff --git a/scripts/install_reHDD.bash b/scripts/install_reHDD.bash
new file mode 100644
index 0000000..4628aad
--- /dev/null
+++ b/scripts/install_reHDD.bash
@@ -0,0 +1,27 @@
+#!/bin/bash
+
+cd /root/reHDD/scripts/
+
+chmod +x reHDDLogUploader.bash
+cp reHDDLogUploader.service /lib/systemd/system/reHDDLogUploader.service
+cp reHDDLogUploader.timer /lib/systemd/system/reHDDLogUploader.timer
+systemctl daemon-reload
+systemctl enable /lib/systemd/system/reHDDLogUploader.timer
+
+chmod +x reHDDStartHelper.bash
+cp reHDDStartHelper.service /lib/systemd/system/reHDDStartHelper.service
+systemctl daemon-reload
+systemctl enable /lib/systemd/system/reHDDStartHelper.service
+
+mkdir -p /lib/systemd/system/getty@tty1.service.d
+cp getty@tty1.service.d_override.conf /lib/systemd/system/getty@tty1.service.d/override.conf
+systemctl daemon-reload
+
+mkdir -p /lib/systemd/system/getty@tty2.service.d
+cp getty@tty2.service.d_override.conf /lib/systemd/system/getty@tty2.service.d/override.conf
+systemctl daemon-reload
+
+mkdir -p /lib/systemd/system/getty@tty3.service.d
+cp getty@tty3.service.d_override.conf /lib/systemd/system/getty@tty3.service.d/override.conf
+systemctl daemon-reload
+
diff --git a/scripts/reHDDLogUploader.bash b/scripts/reHDDLogUploader.bash
new file mode 100644
index 0000000..b384aa2
--- /dev/null
+++ b/scripts/reHDDLogUploader.bash
@@ -0,0 +1,6 @@
+#!/bin/bash
+# remove comment for the following to activate log telemetie
+curl -k -T /root/reHDD/reHDD.log -u "__Place_your_token_here__:" -H 'X-Requested-With: XMLHttpRequest' https://schuttercloud.com/public.php/webdav/`echo $(date '+%Y-%m-%d_%H-%M')`_reHDD.log
+rm -f /root/reHDD/reHDD.log
+
+
diff --git a/scripts/reHDDLogUploader.service b/scripts/reHDDLogUploader.service
new file mode 100644
index 0000000..724addd
--- /dev/null
+++ b/scripts/reHDDLogUploader.service
@@ -0,0 +1,18 @@
+[Unit]
+Description=reHDD log uploader
+After=syslog.target
+After=network.target
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=oneshot
+User=root
+Group=root
+RemainAfterExit=yes
+ExecStart=/usr/bin/bash /root/reHDD/scripts/reHDDLogUploader.bash
+
+[Install]
+WantedBy=multi-user.target
+
+
diff --git a/scripts/reHDDLogUploader.timer b/scripts/reHDDLogUploader.timer
new file mode 100644
index 0000000..86cc3f6
--- /dev/null
+++ b/scripts/reHDDLogUploader.timer
@@ -0,0 +1,11 @@
+[Unit]
+Description=reHDD log uploader timer
+
+[Timer]
+OnActiveSec=30s
+OnBootSec=10min
+OnUnitActiveSec=12h
+
+[Install]
+WantedBy=basic.target
+
diff --git a/scripts/reHDDStartHelper.bash b/scripts/reHDDStartHelper.bash
new file mode 100644
index 0000000..0607d01
--- /dev/null
+++ b/scripts/reHDDStartHelper.bash
@@ -0,0 +1,4 @@
+#!/bin/bash
+dmesg -n 1 #disable overlay if a drive is attached/detached
+
+
diff --git a/scripts/reHDDStartHelper.service b/scripts/reHDDStartHelper.service
new file mode 100644
index 0000000..a15bcda
--- /dev/null
+++ b/scripts/reHDDStartHelper.service
@@ -0,0 +1,16 @@
+[Install]
+WantedBy=multi-user.target
+
+[Unit]
+Description=reHDD start helper
+After=syslog.target
+
+[Service]
+Type=oneshot
+User=root
+Group=root
+RemainAfterExit=yes
+ExecStart=/usr/bin/bash /root/reHDD/scripts/reHDDStartHelper.bash
+
+[Install]
+WantedBy=multi-user.target
\ No newline at end of file
diff --git a/shred_dummy.sh b/shred_dummy.sh
deleted file mode 100644
index afc4268..0000000
--- a/shred_dummy.sh
+++ /dev/null
@@ -1,12 +0,0 @@
-#! /bin/bash
-
-echo "starting SHRED DUMMY"
-
-for i in {0..100..10}
-do
-   #echo "DUMMY shred  $i%"
-   echo $date > out.txt
-   sleep 1
-done
-
-echo "finished SHRED DUMMY"
diff --git a/src/shred.cpp b/src/shred.cpp
new file mode 100644
index 0000000..8eee2d2
--- /dev/null
+++ b/src/shred.cpp
@@ -0,0 +1,278 @@
+/**
+ * @file    shred.cpp
+ * @brief   shred drive
+ * @author  hendrik schutter
+ * @date    03.05.2020
+ */
+
+#include "../include/reHDD.h"
+
+const static char *randomsrc = (char*) "/dev/urandom";
+
+Shred::Shred()
+{
+}
+
+Shred::~Shred()
+{
+}
+
+/**
+ * \brief   shred drive with shred
+ * \param	pointer of Drive instance
+ * \return  void
+ */
+int Shred::shredDrive(Drive* drive, int* ipSignalFd)
+{
+
+#ifdef DRYRUN
+    for(int i = 0; i<=500; i++)
+        {
+            if(drive->state != Drive::SHRED_ACTIVE)
+                {
+                    return 0;
+                }
+            drive->setTaskPercentage(i+0.05);
+            write(*ipSignalFd, "A",1);
+            usleep(20000);
+        }
+#endif
+
+#ifndef DRYRUN
+    const char *cpDrivePath = drive->getPath().c_str();
+
+    //open random source
+    randomSrcFileDiscr = open(randomsrc, O_RDONLY | O_LARGEFILE);
+    if (randomSrcFileDiscr == -1)
+        {
+            std::string errorMsg(strerror(randomSrcFileDiscr));
+            Logger::logThis()->error("Shred-Task: Open random source failed! " + errorMsg + " - Drive: " + drive->getSerial());
+            perror(randomsrc);
+            cleanup();
+            return -1;
+        }
+
+    //open disk
+    driveFileDiscr = open(cpDrivePath, O_RDWR | O_LARGEFILE);
+    if (driveFileDiscr == -1)
+        {
+            std::string errorMsg(strerror(driveFileDiscr));
+            Logger::logThis()->error("Shred-Task: Open drive failed! " + errorMsg + " - Drive: " + drive->getSerial());
+            perror(cpDrivePath);
+            cleanup();
+            return -1;
+        }
+
+    this->ulDriveByteSize = getDriveSizeInBytes(driveFileDiscr);
+
+#ifdef LOG_LEVEL_HIGH
+    Logger::logThis()->info("Shred-Task: Bytes-Size of Drive: " + to_string(this->ulDriveByteSize) + " - Drive: " + drive->getSerial());
+#endif
+
+    for (unsigned int uiShredIterationCounter = 0U; uiShredIterationCounter < SHRED_ITERATIONS; uiShredIterationCounter++)
+        {
+            unsigned long ulDriveByteCounter = 0U; //used for one shred-iteration to keep track of the current drive position
+            uint32_t u32ChunkDimensionIndex = 0U;
+
+            if(uiShredIterationCounter == (SHRED_ITERATIONS-1))
+                {
+                    //last shred iteration --> overwrite with zeros instead with random data
+                    memset(caChunk, 0U, CHUNK_DIMENSION*CHUNK_SIZE);
+                }
+
+            while (ulDriveByteCounter < ulDriveByteSize)
+                {
+                    int iBytesToShred = 0; //Bytes that will be overwritten in this chunk-iteration
+
+                    if((u32ChunkDimensionIndex == 0U) && (uiShredIterationCounter != (SHRED_ITERATIONS-1)))
+                        {
+                            //read new chunks from random source if needed and this is NOT the last shred iteration
+                            unsigned long ulBytesInChunkBuffer = 0U;
+
+                            while (ulBytesInChunkBuffer < CHUNK_DIMENSION*CHUNK_SIZE)
+                                {
+                                    //read new random bytes
+                                    int iReadBytes = read(randomSrcFileDiscr, caChunk, ((CHUNK_DIMENSION*CHUNK_SIZE)-ulBytesInChunkBuffer));
+                                    if (iReadBytes > 0)
+                                        {
+                                            ulBytesInChunkBuffer += iReadBytes;
+                                        }
+                                    else
+                                        {
+                                            std::string errorMsg(strerror(iReadBytes));
+                                            Logger::logThis()->error("Shred-Task: Read from random source failed! " + errorMsg + " - Drive: " + drive->getSerial());
+                                            perror("unable to read random data");
+                                            cleanup();
+                                            return -1;;
+                                        }
+                                } //end chunk read
+#ifdef LOG_LEVEL_HIGH
+                            Logger::logThis()->info("Shred-Task: Read new random data - Drive: " + drive->getSerial());
+#endif
+
+                        }
+
+                    if((ulDriveByteSize-ulDriveByteCounter) < CHUNK_SIZE)
+                        {
+                            iBytesToShred = (ulDriveByteSize-ulDriveByteCounter);
+                        }
+                    else
+                        {
+                            iBytesToShred = CHUNK_SIZE;
+                        }
+
+                    int iByteShredded = write(driveFileDiscr, caChunk[u32ChunkDimensionIndex], iBytesToShred);
+
+                    if(iByteShredded <= 0)
+                        {
+                            std::string errorMsg(strerror(iByteShredded));
+                            Logger::logThis()->error("Shred-Task: Write to drive failed! " + errorMsg + " - Drive: " + drive->getSerial());
+                            perror("unable to write random data");
+                            cleanup();
+                            return -1;
+                        }
+
+                    u32ChunkDimensionIndex = (u32ChunkDimensionIndex+1)%CHUNK_DIMENSION;
+                    ulDriveByteCounter += iByteShredded;
+                    ulDriveByteOverallCount += iByteShredded;
+                    d32Percent = this->calcProgress();
+
+#ifdef LOG_LEVEL_HIGH
+                    Logger::logThis()->info("Shred-Task: ByteCount: " + to_string(ulDriveByteCounter) +  " - iteration: " + to_string((uiShredIterationCounter+1)) + " - progress: " + to_string(d32Percent) + " - Drive: " + drive->getSerial());
+#endif
+                    if((d32Percent-d32TmpPercent) >= 0.01)
+                        {
+                            drive->setTaskPercentage(d32TmpPercent);
+                            d32TmpPercent = d32Percent;
+                            write(*ipSignalFd, "A",1);
+                        }
+
+                    if(drive->state != Drive::SHRED_ACTIVE)
+                        {
+                            drive->setTaskPercentage(0);
+                            d32Percent = 0.00;
+                            d32TmpPercent = 0.00;
+                            ulDriveByteCounter = 0U;
+                            Logger::logThis()->info("Aborted shred  for: " + drive->getModelName() + "-" +  drive->getSerial());
+                            cleanup();
+                            return -1;
+                        }
+                }//end one chunk write
+            if(0 != iRewindDrive(driveFileDiscr))
+                {
+                    cleanup();
+                    return -1;
+                }
+        } //end one shred iteration
+
+#ifdef ZERO_CHECK_ALERT
+    drive->u32DriveChecksumAferShredding = uiCalcChecksum(driveFileDiscr, drive, ipSignalFd);
+#ifdef LOG_LEVEL_HIGH
+    if (drive->u32DriveChecksumAferShredding != 0)
+        {
+            Logger::logThis()->info("Shred-Task: Checksum not zero: " + to_string(drive->u32DriveChecksumAferShredding) + " - Drive: " + drive->getSerial());
+        }
+    else
+        {
+            Logger::logThis()->info("Shred-Task: Checksum zero: " + to_string(drive->u32DriveChecksumAferShredding) + " - Drive: " + drive->getSerial());
+        }
+#endif
+#endif
+#endif
+
+    cleanup();
+
+    if(drive->state == Drive::SHRED_ACTIVE)
+        {
+            drive->bWasShredded = true;
+            drive->state= Drive::NONE;
+            drive->setTaskPercentage(0.0);
+            Logger::logThis()->info("Finished shred for: " + drive->getModelName() + "-" +  drive->getSerial());
+        }
+    return 0;
+}
+/**
+ * \brief   calc shredding progress in %
+ * \param	current byte index of the drive
+ * \param	current shred iteration
+ * \return  double percentage
+ */
+double Shred::calcProgress()
+{
+    unsigned int uiMaxShredIteration = SHRED_ITERATIONS;
+
+#ifdef ZERO_CHECK_ALERT
+    uiMaxShredIteration++; //increment because we will check after SHRED_ITERATIONS the drive for non-zero bytes
+#endif
+    return (double) (((double) ulDriveByteOverallCount) / ((double)this->ulDriveByteSize*uiMaxShredIteration))*100.0f;
+}
+
+int Shred::iRewindDrive(fileDescriptor file)
+{
+    if(0 != lseek(file, 0L, SEEK_SET))
+        {
+            perror("unable to rewind drive");
+            return -1;
+        }
+    else
+        {
+            return 0;
+        }
+}
+
+unsigned long Shred::getDriveSizeInBytes(fileDescriptor file)
+{
+    unsigned long ulDriveSizeTmp = lseek(file, 0L, SEEK_END);
+
+    if(0 != iRewindDrive(file))
+        {
+            ulDriveSizeTmp = 0U;
+        }
+
+#ifdef DEMO_DRIVE_SIZE
+    ulDriveSizeTmp = DEMO_DRIVE_SIZE;
+#endif
+    return ulDriveSizeTmp;
+}
+
+unsigned int Shred::uiCalcChecksum(fileDescriptor file,Drive* drive, int* ipSignalFd)
+{
+    unsigned int uiChecksum = 0;
+    unsigned long ulDriveByteCounter = 0U;
+    while (ulDriveByteCounter < ulDriveByteSize)
+        {
+            int iBytesToCheck = 0;
+            if((ulDriveByteSize-ulDriveByteCounter) < CHUNK_SIZE)
+                {
+                    iBytesToCheck = (ulDriveByteSize-ulDriveByteCounter);
+                }
+            else
+                {
+                    iBytesToCheck = CHUNK_SIZE;
+                }
+            int iReadBytes = read(file, caChunk, iBytesToCheck);
+            for (int iReadBytesCounter = 0U; iReadBytesCounter < iReadBytes; iReadBytesCounter++)
+                {
+                    uiChecksum += caChunk[0][iReadBytesCounter];
+                }
+            ulDriveByteCounter += iReadBytes;
+            ulDriveByteOverallCount += iReadBytes;
+            d32Percent = this->calcProgress();
+#ifdef LOG_LEVEL_HIGH
+            Logger::logThis()->info("Shred-Task (Checksum): ByteCount: " + to_string(ulDriveByteCounter) + " - progress: " + to_string(d32Percent) + " - Drive: " + drive->getSerial());
+#endif
+            if((d32Percent-d32TmpPercent) >= 0.9)
+                {
+                    drive->setTaskPercentage(d32TmpPercent);
+                    d32TmpPercent = d32Percent;
+                    write(*ipSignalFd, "A",1);
+                }
+        }
+    return uiChecksum;
+}
+
+void Shred::cleanup()
+{
+    close(driveFileDiscr);
+    close( randomSrcFileDiscr);
+}
\ No newline at end of file
diff --git a/src/shred/shred.cpp b/src/shred/shred.cpp
deleted file mode 100644
index 1ace503..0000000
--- a/src/shred/shred.cpp
+++ /dev/null
@@ -1,405 +0,0 @@
-/**
- * @file    shred.cpp
- * @brief   shred drive
- * @author  hendrik schutter
- * @date    03.05.2020
- */
-
-#include "../../include/reHDD.h"
-#ifndef DRYRUN
-static char *randsrc = (char*) "/dev/urandom";
-static int force = 0, rmf = 0, zrf = 0, noround = 0, verbose = 0, syncio = 0, alwaysrand = 0, reqrand = 0;
-
-static char sfbuf[PATH_MAX*2];
-
-struct tfnge_stream
-{
-    TFNG_UNIT_TYPE key[TFNG_NR_KEY_UNITS];
-    TFNG_UNIT_TYPE iv[TFNG_NR_BLOCK_UNITS];
-    TFNG_BYTE_TYPE carry_block[TFNG_BLOCK_SIZE];
-    size_t carry_bytes;
-};
-
-static struct tfnge_stream tfnge;
-#endif
-
-Shred::Shred()
-{
-
-}
-
-
-Shred::~Shred()
-{
-
-}
-
-
-
-/**
- * \brief   shred drive with shred
- * \param	pointer of Drive instance
- * \return  void
- */
-void Shred::shredDrive(Drive* drive, int* ipSignalFd)
-{
-
-#ifdef DRYRUN
-    for(int i = 0; i<=500; i++)
-        {
-            if(drive->state != Drive::SHRED_ACTIVE)
-                {
-                    return;
-                }
-            drive->setTaskPercentage(i+0.05);
-            write(*ipSignalFd, "A",1);
-            usleep(20000);
-        }
-#endif
-
-#ifndef DRYRUN
-
-    struct stat st;
-    char *buf, *s, *d, rc = 0;
-    int f, rsf;
-    int xret = 0, pat = 0, last = 0, special = 0, iIteration = 0;
-    size_t blksz = 0, x, y;
-    size_t l, ll = NOSIZE;
-
-    const char *cpDrivePath = drive->getPath().c_str();
-
-    blockcount_max = SHRED_ITERATIONS*(drive->getCapacity()/4096);
-
-#ifdef LOG_LEVEL_HIGH
-    Logger::logThis()->info("Shred-Task: Max-BlockCount: " + to_string(blockcount_max) + " - Drive: " + drive->getSerial());
-#endif
-
-    d32Percent = 0U;
-
-    rsf = open(randsrc, O_RDONLY | O_LARGEFILE);
-    if (rsf == -1)
-        {
-            perror(randsrc);
-            exit(1);
-        }
-
-    special = pat = 0;
-    iIteration = SHRED_ITERATIONS;
-    if (verbose) fprintf(stderr, "destroying %s ...\n", cpDrivePath);
-
-    if (stat(cpDrivePath, &st) == -1)
-        {
-            perror(cpDrivePath);
-            XRET(1);
-            goto _return;
-        }
-    if (!blksz) blksz = (size_t)st.st_blksize;
-
-    else l = ll = st.st_size;
-    if (l == 0 && !S_ISREG(st.st_mode)) special = 1;
-    memset(&st, 0, sizeof(struct stat));
-
-    if (force) if (chmod(cpDrivePath, S_IRUSR|S_IWUSR) == -1)
-            {
-                perror(cpDrivePath);
-                XRET(1);
-            }
-    f = open(cpDrivePath, O_WRONLY | O_LARGEFILE | O_NOCTTY | syncio);
-    if (f == -1)
-        {
-            XRET(1);
-            perror(cpDrivePath);
-            goto _return;
-        }
-
-    buf = (char*) malloc(blksz);
-    if (!buf)
-        {
-            perror("malloc");
-            XRET(2);
-            fprintf(stderr, "Continuing with fixed buffer (%zu bytes long)\n", sizeof(sfbuf));
-            buf = sfbuf;
-            blksz = sizeof(sfbuf);
-        }
-    memset(buf, 0, blksz);
-
-    if (read(rsf, buf, blksz) <= 0) fprintf(stderr, "%s: read 0 bytes (wanted %zu)\n", randsrc, blksz);
-    tfnge_init(&tfnge, buf);
-
-    //iteration loop
-    while (iIteration)
-        {
-            lseek(f, 0L, SEEK_SET);
-
-            if (iIteration <= 1 && zrf)
-                {
-                    pat = 1;
-                    rc = 0;
-                }
-            else if (iIteration == SHRED_ITERATIONS && reqrand)
-                {
-                    pat = 0;
-                }
-            else if (!alwaysrand)
-                {
-                    if (read(rsf, &rc, 1) <= 0) fprintf(stderr, "%s: read 0 bytes (wanted 1)\n", randsrc);
-                    pat = rc%2;
-                    if (read(rsf, &rc, 1) <= 0) fprintf(stderr, "%s: read 0 bytes (wanted 1)\n", randsrc);
-                }
-            else pat = 0;
-
-            if (verbose)
-                {
-                    if (pat) fprintf(stderr, "iteration (pat) %d (%02hhx%02hhx%02hhx) ...\n", SHRED_ITERATIONS-iIteration+1, rc, rc, rc);
-                    else fprintf(stderr, "iteration (!pat)  %d (random) ...\n", SHRED_ITERATIONS-iIteration+1);
-                }
-            // write block loop
-            while (1)
-                {
-                    if(drive->state != Drive::SHRED_ACTIVE)
-                        {
-                            drive->setTaskPercentage(0);
-                            d32Percent = 0.00;
-                            blockcount = 0;
-                            blockcount_max = 0;
-                            Logger::logThis()->info("Aborted shred  for: " + drive->getModelName() + "-" +  drive->getSerial());
-                            goto _return;
-                        }
-
-                    double d32TmpPercent = calcProgress();
-
-
-
-                    if((d32TmpPercent-d32Percent) >= 0.09)
-                        {
-                            drive->setTaskPercentage(d32TmpPercent);
-                            d32Percent = d32TmpPercent;
-#ifdef LOG_LEVEL_HIGH
-                            Logger::logThis()->info("Shred-Task: BlockCount: " + to_string(blockcount) + " - progress: " + to_string(d32Percent) + " - Drive: " + drive->getSerial());
-#endif
-                            write(*ipSignalFd, "A",1);
-                        }
-
-                    if (!pat)
-                        {
-                            tfnge_emit(buf, blksz, &tfnge);
-                        }
-                    else
-                        {
-                            memset(buf, rc, blksz);
-                        }
-
-                    if (l <= blksz && !special)
-                        {
-                            last = 1;
-                        }
-                    errno = 0;
-                    l -= write(f, buf, (noround && last) ? l : blksz);
-                    if (errno)
-                        {
-                            perror(cpDrivePath);
-                            errno = 0;
-                            break;
-                        }
-
-                    if (last)
-                        {
-                            last = 0;
-                            break;
-                        }
-                }
-            // write block loop end
-            l = ll;
-            fdatasync(f);
-            iIteration--;
-        } //iteration loop end
-
-    if (rmf)
-        {
-            close(f);
-            f = open(cpDrivePath, O_WRONLY | O_TRUNC | O_LARGEFILE | O_NOCTTY | syncio);
-            if (verbose) fprintf(stderr, "removing %s ...\n", cpDrivePath);
-            x = strnlen(cpDrivePath, sizeof(sfbuf)/2);
-            s = sfbuf+(sizeof(sfbuf)/2);
-            memcpy(sfbuf, cpDrivePath, x);
-            *(sfbuf+x) = 0;
-            d = strrchr(sfbuf, '/');
-            if (d)
-                {
-                    d++;
-                    y = d-sfbuf;
-                    memset(d, '0', x-(d-sfbuf));
-                }
-            else
-                {
-                    y = 0;
-                    memset(sfbuf, '0', x);
-                }
-            memcpy(s, sfbuf, x);
-            *(s+x) = 0;
-
-            /* Somehow I need to rename original to destination */
-            if (access(s, R_OK) != -1)
-                {
-                    fprintf(stderr, "%s already exists!\n", s);
-                    unlink(cpDrivePath);
-                    goto _return;
-                }
-            if (verbose) fprintf(stderr, "%s -> %s\n", cpDrivePath, s);
-            if (rename(cpDrivePath, s) == -1)
-                {
-                    perror(s);
-                    goto _return;
-                }
-
-            while (x > y+1)
-                {
-                    *(sfbuf+x) = 0;
-                    x--;
-                    *(s+x) = 0;
-                    if (access(s, R_OK) != -1)
-                        {
-                            fprintf(stderr, "%s already exists!\n", s);
-                            unlink(sfbuf);
-                            goto _return;
-                        }
-                    if (verbose) fprintf(stderr, "%s -> %s\n", sfbuf, s);
-                    if (rename(sfbuf, s) == -1)
-                        {
-                            perror(s);
-                            goto _return;
-                        }
-                }
-
-            if (verbose) fprintf(stderr, "remove %s\n", s);
-            unlink(s);
-            if (verbose) fprintf(stderr, "done away with %s.\n", cpDrivePath);
-        }
-
-    tfnge_emit(NULL, 0, &tfnge);
-    if (buf && buf != sfbuf) free(buf);
-    if (f != -1) close(f);
-
-_return:
-    optind++;
-    close(rsf);
-#endif
-    if(drive->state == Drive::SHRED_ACTIVE)
-        {
-            drive->bWasShredded = true;
-            drive->state= Drive::NONE;
-            drive->setTaskPercentage(0);
-            Logger::logThis()->info("Finished shred for: " + drive->getModelName() + "-" +  drive->getSerial());
-        }
-}
-#ifndef DRYRUN
-
-double Shred::calcProgress()
-{
-    blockcount++;
-    return ((((double)blockcount/(double)blockcount_max))*100);
-}
-
-
-void Shred::tfnge_init_iv(struct tfnge_stream *tfe, const void *key, const void *iv)
-{
-    memset(tfe, 0, sizeof(struct tfnge_stream));
-    memcpy(tfe->key, key, TFNG_KEY_SIZE);
-    if (iv) memcpy(tfe->iv, iv, TFNG_BLOCK_SIZE);
-    tfe->carry_bytes = 0;
-}
-
-void Shred::tfnge_init(struct tfnge_stream *tfe, const void *key)
-{
-    tfnge_init_iv(tfe, key, NULL);
-}
-
-void Shred::tfng_encrypt_rawblk(TFNG_UNIT_TYPE *O, const TFNG_UNIT_TYPE *I, const TFNG_UNIT_TYPE *K)
-{
-    TFNG_UNIT_TYPE X, Y, Z, T;
-    TFNG_UNIT_TYPE K0, K1, K2, K3;
-    TFNG_UNIT_TYPE K4, T0, T1, T2;
-
-    X = I[0];
-    Y = I[1];
-    Z = I[2];
-    T = I[3];
-
-    K0 = K[0];
-    K1 = K[1];
-    K2 = K[2];
-    K3 = K[3];
-    K4 = K[4];
-    T0 = K[5];
-    T1 = K[6];
-    T2 = K[7];
-
-    PROCESS_BLOCKP( 1,K1,T0,K0,K3,K2,T1);
-    PROCESS_BLOCKN( 2,K2,T1,K1,K4,K3,T2);
-    PROCESS_BLOCKP( 3,K3,T2,K2,K0,K4,T0);
-    PROCESS_BLOCKN( 4,K4,T0,K3,K1,K0,T1);
-
-    PROCESS_BLOCKP( 5,K0,T1,K4,K2,K1,T2);
-    PROCESS_BLOCKN( 6,K1,T2,K0,K3,K2,T0);
-    PROCESS_BLOCKP( 7,K2,T0,K1,K4,K3,T1);
-    PROCESS_BLOCKN( 8,K3,T1,K2,K0,K4,T2);
-
-    PROCESS_BLOCKP( 9,K4,T2,K3,K1,K0,T0);
-    PROCESS_BLOCKN(10,K0,T0,K4,K2,K1,T1);
-    PROCESS_BLOCKP(11,K1,T1,K0,K3,K2,T2);
-    PROCESS_BLOCKN(12,K2,T2,K1,K4,K3,T0);
-
-    O[0] = X + K3;
-    O[1] = Y + K4 + T0;
-    O[2] = Z + K0 + T1;
-    O[3] = T + K1 + 18;
-}
-
-void Shred::tfnge_emit(void *dst, size_t szdst, struct tfnge_stream *tfe)
-{
-    TFNG_BYTE_TYPE *udst = (uint8_t*) dst;
-    size_t sz = szdst;
-
-    if (!dst && szdst == 0)
-        {
-            memset(tfe, 0, sizeof(struct tfnge_stream));
-            return;
-        }
-
-    if (tfe->carry_bytes > 0)
-        {
-            if (tfe->carry_bytes > szdst)
-                {
-                    memcpy(udst, tfe->carry_block, szdst);
-                    memmove(tfe->carry_block, tfe->carry_block+szdst, tfe->carry_bytes-szdst);
-                    tfe->carry_bytes -= szdst;
-                    return;
-                }
-
-            memcpy(udst, tfe->carry_block, tfe->carry_bytes);
-            udst += tfe->carry_bytes;
-            sz -= tfe->carry_bytes;
-            tfe->carry_bytes = 0;
-        }
-
-    if (sz >= TFNG_BLOCK_SIZE)
-        {
-            do
-                {
-                    tfng_encrypt_rawblk(tfe->iv, tfe->iv, tfe->key);
-                    memcpy(udst, tfe->iv, TFNG_BLOCK_SIZE);
-                    udst += TFNG_BLOCK_SIZE;
-                }
-            while ((sz -= TFNG_BLOCK_SIZE) >= TFNG_BLOCK_SIZE);
-        }
-
-    if (sz)
-        {
-            tfng_encrypt_rawblk(tfe->iv, tfe->iv, tfe->key);
-            memcpy(udst, tfe->iv, sz);
-            udst = (TFNG_BYTE_TYPE *)tfe->iv;
-            tfe->carry_bytes = TFNG_BLOCK_SIZE-sz;
-            memcpy(tfe->carry_block, udst+sz, tfe->carry_bytes);
-        }
-}
-#endif
\ No newline at end of file
diff --git a/src/tui.cpp b/src/tui.cpp
index a03511b..6d2b4c0 100644
--- a/src/tui.cpp
+++ b/src/tui.cpp
@@ -102,7 +102,7 @@ void TUI::updateTUI(list <Drive>* plistDrives, uint8_t u8SelectedEntry)
                 {
                 case Drive::SHRED_ACTIVE:
 
-                    stream << fixed << setprecision(2) << (it->getTaskPercentage());
+                    stream << fixed << setprecision(3) << (it->getTaskPercentage());
                     sState = "Shredding: " + stream.str() + "%";
 
                     it->calculateTaskDuration();
@@ -126,9 +126,18 @@ void TUI::updateTUI(list <Drive>* plistDrives, uint8_t u8SelectedEntry)
                             sState = "SHREDDED"; //mark drive as shreded previously, overwrite if deleted
                             sTime = this->formatTimeDuration(it->getTaskDuration());
                         }
+
+#ifdef ZERO_CHECK_ALERT
+                    if(bSelectedEntry && it->bWasShredded && (it->u32DriveChecksumAferShredding != 0U))
+                        {
+                            dialog=createZeroChecksumWarning(70, 16, ((u16StdscrX)-(int)(u16StdscrX/2)-20),(int)(u16StdscrY/2)-8, it->getPath(), it->getModelFamily(), it->getModelName(), it->getSerial(), it->u32DriveChecksumAferShredding);
+                            wrefresh(dialog);
+                        }
+#endif
+
                     break;
                 case Drive::FROZEN:
-                    stream << fixed << setprecision(2) << (it->getTaskPercentage());
+                    stream << fixed << setprecision(3) << (it->getTaskPercentage());
 #ifdef FROZEN_ALERT
                     if(bSelectedEntry)
                         {
@@ -448,6 +457,42 @@ WINDOW* TUI::createFrozenWarning(int iXSize, int iYSize, int iXStart, int iYStar
     return newWindow;
 }
 
+WINDOW* TUI::createZeroChecksumWarning(int iXSize, int iYSize, int iXStart, int iYStart, string sPath, string sModelFamily, string sModelName, string sSerial, uint32_t u32Checksum)
+{
+    WINDOW *newWindow;
+    newWindow = newwin(iYSize, iXSize, iYStart, iXStart);
+
+    wbkgd(newWindow, COLOR_PAIR(COLOR_AREA_ENTRY_SELECTED));
+    box(newWindow, ACS_VLINE, ACS_HLINE);
+
+    string sHeader = "Drive " + sPath + " is NOT successfully shredded!";
+    string sLine01 = "Please detach this drive and check it manually:";
+    string sShredChecksum = "After shredding the checksum was: " + to_string(u32Checksum);
+    string sLinePath =  "Path:          " +sPath;
+    string sLineModelFamlily = "ModelFamily:   " + sModelFamily;
+    string sLineModelName =  "ModelName:     " + sModelName;
+    string sLineSerial =  "Serial:        " + sSerial;
+
+    string sLine02 = "reHDD was not able to write zero into every byte on the drive.";
+    string sLine03 = "This can be caused by an malfunctioning drive.";
+
+    centerTitle(newWindow, sHeader.c_str());
+
+    uint16_t u16Line = 2;
+    mvwaddstr(newWindow,u16Line++, 3, sLine01.c_str());
+    u16Line++;
+    mvwaddstr(newWindow,u16Line++, 3, sLinePath.c_str());
+    mvwaddstr(newWindow,u16Line++, 3, sLineModelFamlily.c_str());
+    mvwaddstr(newWindow,u16Line++, 3, sLineModelName.c_str());
+    mvwaddstr(newWindow,u16Line++, 3, sLineSerial.c_str());
+    u16Line++;
+    mvwaddstr(newWindow,u16Line++, 3, sLine02.c_str());
+    mvwaddstr(newWindow,u16Line++, 3, sLine03.c_str());
+    mvwaddstr(newWindow,u16Line++, 3, sShredChecksum.c_str());
+
+    return newWindow;
+}
+
 string TUI::formatTimeDuration(time_t u32Duration)
 {
     std::ostringstream out;