Encrypt Files on Your SD Card Using Your Android Phone

Edited by Clifford, Charmed, Lynn, Lhynne27 and 21 others

Android devices come with many security options, the most obvious being the option to set a password or visual pattern lock to stop others from accessing your device. But what if you need another layer of security for sensitive files? Consider encrypting files on your SD card for added peace of mind.

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A potential downside to filing encryption is that it forces you to enter a password every time you want to access an encrypted file. However, in special cases where vital personal data is stored on the SD card, it could be a great extra layer of protection for your files. Here's how to set it up.

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Enable A Password On Your Phone

  1. 1
    If you don't secure your phone with a password, you will find that the Encrypt SD card menu does not enable you to select any files to encrypt
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    To choose any files on your SD card to encrypt, you need to add a memorable six-character password to your device.
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  2. 2
    Tap on the "Settings" icon on your Android phone.
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  3. 3
    Then tap on "Security".
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  4. 4
    Tap on the "Set Up Screen Lock" tab and select the password option from the list
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    Next, enter a secure password that you will be able to remember. Once you are done setting up your password, it will go back to the "Security" menu. You'll notice the "Change Screen Lock" option has appeared on the list. It means that a password has now been set up on your phone.
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Encrypt Your SD card

  1. 1
    Tap on the "Settings" icon on your Android phone.
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  2. 2
    Then tap on "Security".
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    This menu includes a wide range of settings and toggles that you can alter to change the current, and add new security elements to your Android device.
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  3. 3
    Tap on the "Security" button and then on "Encryption"
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    Next, tap the "Encrypt External SD card" tab located at the top of this menu to begin the encryption process. You should also check out the encrypt device option, which outlines the process and results of encrypting your phone.
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  4. 4
    Now you must set a password on the SD card
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    Insert the SD card into the phone and then follow the prompts that will allow you to set your SD card password. Your password must be a minimum of six characters long and include at least one letter. Confirm your password by adding it a second time. For your own safety, it's a good idea to write your password down. You should keep that written record in a secure location.
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  5. 5
    After your new password has been set, go back to the external SD card menu
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    You should be able to select the types of files you want to encrypt on your SD card. If you choose to encrypt media files, anticipate the encryption process to take a while, depending on the number of media files you have on your phone.
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  6. 6
    The phone should display a few pages of information, which will explain the encryption process to you
    .
    The encryption process will start after you have confirmed that you have read the details (it's not a bad idea to actually read them).
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  7. 7
    The encryption process could take from a few seconds to several minutes, depending on the size of your SD card
    .
    You can check the process by pulling down the notification area, which will show how long is remaining.
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  8. 8
    After the process is finished, your phone will take you back to your home screen
    .
    You'll also see in the "Notifications" area if the SD card is already encrypted.
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  9. 9
    Don't forget that every time you try to access the contents of your SD card, you need to enter the password that you have just set up.
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Encryption, Explained

Unfortunately, it is virtually impossible to access or decrypt the files on your SD card without the right password. Android's encryption algorithm is based on two major factors - the mobile device and the password. Lose any of these, and your encrypted SD card files will be inaccessible. You can only decrypt the SD card files by inserting the SD card into the mobile device that was used to encrypt it and then entering the correct password when the device is powered on.

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The password or key is stored in your mobile device's Random Access Memory (RAM). Theoretically, every time you access a file from your encrypted SD card, Android goes through the RAM first to retrieve the key and use it to decrypt the file. This is the reason why dealing with encrypted data is relatively slower than accessing unencrypted files.

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Why does it work this way? What does encryption mean anyway?

Encryption is essentially classified as a high-level data storage security process. When you encrypt a file, you are altering its form using a specific algorithm so that the operating system will not be able to readily classify or identify it. With advancements in information security, the encryption algorithms being employed nowadays are basically "fool-proof". This means that there is no viable way of opening an encrypted file other than getting a hold of the key. Hundreds of supercomputers could take thousands of years to open an encrypted file.

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Encryption is designed to work this way for one obvious reason: Security. This ensures that sensitive data will not be compromised should it fall into the hands of intruders. But the catch is, it could also work against you if you are not mindful.

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There are accounts of encrypted data storage media being decrypted by freezing. This process is fairly sophisticated and would require considerable expertise to carry out, yet it still doesn't guarantee successful decryption. This process basically involves the freezing the device by any logical means possible, in order to slow down the vanishing of data from the RAM after it is powered down.

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With the RAM data intact, a computer expert could copy the data to a file and use programs that could automatically analyze it, and because the encryption key is stored in the RAM as the mobile device was powered up, there is a good chance that the key can be retrieved using this process. However, for this to work, two important conditions must be satisfied - the device is powered on and it was powered on using the correct encrypted password. This means that the freeze process can only be used if you have turned on your device using the correct password beforehand, but forgot the password later on with the device still powered on.

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The bottom line is that forgetting your encryption password means trouble. It is like locking yourself up in a prison you built. For this reason, you should consider all factors before encrypting your SD card. One good rule of thumb: if it's not that sensitive, stay off the encryption route, especially if you have a bad memory.

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Tips Tricks & Warnings

  • There is no limit to the files that you can encrypt on your SD card, however, it will take some time if you happen to encrypt several files at once.
  • Once your SD card is encrypted using your phone, you cannot use the files on the SD card on other phones unless you decrypt it first.
  • Performing a Factory Reset on your phone will make the encrypted files on your SD card unusable.

Questions and Answers

How do I transfer music from my cellphone to the SD card?

I can't transfer music from my phone to the SD card in my phone

If you are transferring music from your computer, then you will need to ensure that, when you drag and click your music, you are releasing the music into the SD card folder rather than your internal memory of your device.

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Are the music files stored in your phone's internal memory? If yes, and you are using an Android Smartphone, you can easily move the files using a file manager app from the Play Store. Get something like Es File Explorer, seen here:

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https://play.google.com/store/apps/details?id=com.estrongs.android.pop

Once installed, you can browse your phone's internal storage for the files and copy/cut/paste them to your external SD card.

I have encrypted the SD card on Galaxy S4, but all the files are still visible even though I entered the password after restart. Why? Then what is does it mean encryption?

I have encrypted the SD card on Galaxy S4, but still, all the files are visible even though I entered the password after restart. Why? Then what is does it mean encryption?

The encryption process means that no one will be able to take any of your information off your SD card without the password. The files may be visible, but people will not be able to open or copy the files without the password.

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See more questions like this: Can I transfer files off my phone's encrypted microSD card to my PC

What if you have secured your phone with a password, and you still can't encrypt the SD card then what?

I believe you are referring to phone lock - like password or pattern, since there is no other security that you can apply on the phone (aside from antivirus applications). If you have a security lock on your Android phone, you should be able to encrypt your SD card on your mobile phone. If you still can't encrypt the mobile phone, you can simply do a Factory Reset on the phone to reset everything on your phone.

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If you cannot encrypt your SD card for any reason, you can simply download an application from your Google Play store to encrypt your files. You can download an application called Encryption Manager. This application works the same as using the direct feature to encrypt your phone's SD card files. Please note that this is not a free application. The Lite version of this app can only encrypt up to 5 files, while the full version is unlimited.

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If you want to know more about the app, go to this link: https://play.google.com/store/apps/details?id=com.giraone.encmanlite

See more questions like this: Does encryption relate to locking

See more questions like this: I encrypted my own Android phone, including the external SD card to use it and test it's performance and here is what I noted: when I tried to revert back to normal (without encryption), the ONLY possible way is to Factory Reset which results in losing al

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See more questions like this: What will I do in that kind of situation? Shall I reset my phone

What if I'm using multiple SD cards and only want to encrypt one of them?

One SD card I keep personal info on and would like to encrypt it. The others I use for pictures and movies that I transfer back and forth with the home computer. Will the Galaxy Tab 3 know if the card requires a password or not? Also, how would I add files to the encrypted SD card from another source, like the home computer?

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Yes, your Galaxy Tab 3 will be able to detect which one is encrypted and it will demand the necessary security steps in order to be able to access it.

In order for you to be able to add files to the encrypted SD card, you would need to follow the security steps in order to enter it. Once you've done that and authorized the communication between the SD card and the computer, things will function as normal.

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I have decrypted my SD card, but still I have to put in a password to open my mobile. I want to disable that without formatting?

  • Go to your Settings application.
  • Tap the Device tab.
  • Tap the Lock screen panel.
  • Tap Screen lock and select Swipe to return your phone to its original lock settings.

If you have problems with any of the steps in this article, please post in the comments section below.

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Article Info

Categories : General Android Mobiles & Tablets

Recent edits by: fleurdawkins, reeeee, Juliem

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