#StackBounty: #macos #external-hard-drive #encryption #time-machine #disk-utility External disk with encrypted Time Machine partition d…

Bounty: 50

I’m not sure when this started, maybe when I setup my Time Machine partition to be encrypted or maybe at a particular OS update, but the Time Machine drive no longer ejects properly. I’d love some help on this one!

Here’s what happens:

  • I have an external drive with two partitions: an encrypted partition for Time Machine, and another AFPS (Encrypted) one called “Extras”. The drive plugs directly into my MacBook Pro 2015 15″ running macOS 10.14.4

  • On a fresh restart with the drive plugged into a USB port, the two partitions appear normally in both Finder and Disk Utility. Time Machine works and everything is good.

  • If I eject the drive (either from Finder or Disk Utility), it appears to eject normally (disappearing from Finder, greying out in Disk Utility) until I actually pull the USB cable out of the MacBook. Instead of the greyed-out drive disappearing altogether from Disk Utility, nothing changes.

  • If I plug the drive back in, then the Extras drive appears again in Finder but Time Machine does not. In Disk Utility, it looks a little weird (see below): a second drive appears with the same name (but nothing under it), and the Extras drive appears under the initial drive.

After plugging hard drive back in

I’ve tried various combinations of unmount/unmountDisk/eject with the diskutil command, and once in a while a command sequence does work… but it’s never repeatable. Now I just have to restart the computer whenever I want to access Time Machine again.

Any ideas here? Thanks for reading.

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#StackBounty: #encryption #gpg #pgp gpg cannot unlock passphrase-less key: "gpg: public key decryption failed: No passphrase given…

Bounty: 50

I have a gpg setup started with older gpg versions and I did not use a passphrase back then. I would type enter directly when prompted for it. I’m not sure if that means the key isn’t encrypted or if it is encrypted with an empty passphrase.

Regardless, when I try to decrypt something that was sent to me recently, gpg needs access to my private key and prompts me for a passphrase but now I cannot use an empty passphrase anymore. gpg fails with:

$ gpg -d foo.asc
(X dialog that prompts me for passphrase, I just press enter)
gpg: public key decryption failed: No passphrase given
gpg: decryption failed: No secret key

I would like to be able to use my keys again. I don’t mind setting a passphrase from now on but I don’t know how:

$ gpg --passwd xxxxxxx@xxxxxxx.com
(X dialog that prompts me for passphrase, I just press enter)
gpg: key xxxxxxxxxxxxxxxx/aaaaaaaaaaaaaaaa: error changing passphrase: No passphrase given
gpg: key xxxxxxxxxxxxxxxx/bbbbbbbbbbbbbbbb: error changing passphrase: No passphrase given
gpg: error changing the passphrase for 'xxxxxxx@xxxxxxx.com': No passphrase given

I am running gpg (GnuPG) 2.2.5 and libgcrypt 1.8.2 on openSUSE 15.0.

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#StackBounty: #javascript #android #react-native #encryption #react-native-android Encrypting the Video file in SD-CARD in react native

Bounty: 100

I was able to successfully encrypt and decrypt the videos using AES encryption. It worked good for smaller videos while for the bigger files it gave us the memory out/Overflow exception. Is there a better way to safe guard the video files where only my application can have the access to it.
I am using this library “node-forge”

How are Video streaming apps like Netflix and Amazon prime are securing the videos locally, which are accessible only through their apps. If they are decrypting the whole file, how is the process so fast?

I was just wondering if we can just corrupt the file and de-corrupt while converting to base-64 ?

This is a E-learning application where videos are accessed through SD Card securely. These Videos should be secured and can be played in only our app.

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#StackBounty: #encryption #bootloader #locked-out #disk-encryption Sony F5121: Forgot Device Encryption Passwort, locked bootloader

Bounty: 50

I forget the device encryption password for my F5121 (locked bootloader). Is there any way to hard-reset the device, so I can use it again (I don’t care about the data on it)?

I already tried some combination with Power Button + Volumne Up/Down, but I don’t see any options popping up.

Also, unlocking the bootloader does not seem to work (probably I should have enabled oem unlocking in the android settings before), it says:

FAILED (remote: 'Command not allowed')

Same error, when trying to flash TWRP.

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#StackBounty: #encryption #luks How do I troubleshoot a disk IO performance issue possibly related to dm-crypt/LUKS?

Bounty: 50


I recently installed Ubuntu 16.04 LTS (kernel 4.8.0-52) on a Lenovo T460p with an i7-6820HQ, 32GB of RAM, and a 512GB Micron 1100 SSD. I checked the full disk encryption box during the installation and used the default partitioning layout. In general, performance is great.

However, over time my builds started running taking about twice as long. Further, during parts of the build that write large files any (non-build) task that requires disk I/O ends up waiting a lot. This includes launching new programs, loading pages in Firefox, etc. In Firefox, for example, I can navigate the UI, switch tabs and everything is fine. But if I follow a link the whole UI locks up until things quiet down.

So in summary, after some period of time, builds suddenly take longer and at certain points during the build the computer is basically unusable.

What can I do to try and diagnose or resolve this issue?

Troubleshooting Info

  • Don’t reboot often so the system is often up for several days before I run into this issue. Once I hit it, I flail for a bit trying to figure out the issue, then reboot so I can keep working.

  • The only thing that resolves the issue is rebooting the machine. I’ve tried exiting all applications, logging out and back in, and dropping the buffer cache (flail theory that as it used memory space disk syncs were happening more frequently) but only rebooting works.

  • As a long shot, I tried the solution to this answer but there was no change in behavior.

  • Running iotop shows the dmcrypt_write thread using 99% I/O whenever I’m experiencing the issues. When I’m not experiencing the issue, I also see dmcrypt_write pop to the top with a relatively high IO % but it doesn’t stay there very long.

  • If I run dd if=/dev/urandom of=$HOME/bigfile bs=10k count=200k; sync when things are working normally, dmcrypt_write will jump to the top for a second or two but it’s no where near the same duration as during one of my builds.

  • A full build generates about 1.4 GB of data. It’s a Java project with several modules. So, lots of little files are created plus some larger JAR files that aggregate all those little files.

  • There is always plenty of memory available and the swap partition is not being used.

  • I have coworkers with similar computers (T460p) also running Ubuntu that are not experiencing this issue. They they all seem to have different SSD brand/models, though.


The issue just surfaced again so I did some more testing based on the reply to this question.

  • The file system is still not mounted with the discard option so I instead ran fstrim assuming that would be somewhat similar to having had the discard option enabled
  • I didn’t do enough timing when the issue first happened, but after running fstrim, build speeds seemed to be back to normal… but after the build completes, the dmcrypt_write thread kicks in and makes the system unusable for a period of time. All and all the total time to build and for the system to become usable seems to be about the same as before.
  • I changed /proc/sys/vm/dirty_ratio to 2 and /proc/sys/vm/dirty_background_ratio to 1 and ran some builds. The builds took longer than normal—about the same as the last time I hit this issue, but the system didn’t seem to lock up as much. Changing it back to 20 and 10 reverted to the behavior mentioned above.
  • On a clean boot, I tried setting /proc/sys/vm/dirty_ratio to 2 and /proc/sys/vm/dirty_background_ratio to 1 and the time was comparable with it at 20 and 10.

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#StackBounty: #18.04 #encryption #ssd #dd #tpm DD a BitLocker/TPM encrypted drive

Bounty: 200

Is it possible to create a bit identical image of a Windows 10 SSD using an Ubuntu live cd/usb?

If I boot into the laptop with the live/cd/usb, I can’t see the drive using fdisk or gparted.

The laptop in question is a Dell Latitute 7490. The laptop has TPM enabled and the drive is encrypted using BitLocker. I have tried disabling BitLocker, but still can’t see the drive to DD it when using a live cd/usb.

Output from sudo lsblk:
enter image description here

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Code to Encrypt Folder Structure Completely

Below is the code to encrypt/decrypt complete folder structure in java

The Code takes 3 parameters:

  • in: String: input path of the folder that u want to encrypt
  • password: String: Used to encrypt/decrypt the files
  • output: String: Folder path in which u wish to publish the encrypted/decrypted files