diff --git a/README.md b/README.md
index 78ff76a..6ebd6a0 100644
--- a/README.md
+++ b/README.md
@@ -77,10 +77,19 @@ Most of the original gocryptfs code was used as is (written in Go) and compiled
 ```
 $ git clone https://github.com/hardcore-sushi/DroidFS.git
 ```
-Gocryptfs need openssl to work:
+Gocryptfs need OpenSSL to work:
 ```
 $ cd DroidFS/app/libgocryptfs
-$ wget -qO - https://www.openssl.org/source/openssl-1.1.1h.tar.gz | tar -xvzf -
+$ wget https://www.openssl.org/source/openssl-1.1.1j.tar.gz
+```
+Verify OpenSSL signature:
+```
+$ wget https://www.openssl.org/source/openssl-1.1.1j.tar.gz.asc
+$ gpg --verify openssl-1.1.1j.tar.gz.asc openssl-1.1.1j.tar.gz
+```
+Continue **ONLY** if the signature is **VALID**.
+```
+$ tar -xvzf openssl-1.1.1j.tar.gz
 ```
 
 #### Build
@@ -96,7 +105,7 @@ $ go get golang.org/x/sys/unix golang.org/x/sys/cpu golang.org/x/crypto/hkdf
 Then, retrieve your Android NDK installation path, usually someting like "/home/\<user\>/AndroidSDK/ndk/\<NDK version\>". We can now start the build process: 
 ```
 $ cd DroidFS/app/libgocryptfs
-$ env ANDROID_NDK_HOME="<your ndk path>" OPENSSL_PATH="./openssl-1.1.1h" ./build.sh
+$ env ANDROID_NDK_HOME="<your ndk path>" OPENSSL_PATH="./openssl-1.1.1j" ./build.sh
  ```
 Then, open the DroidFS project with Android Studio.<br>
 If a device (virtual or physical) is connected, just click on "Run".<br>
diff --git a/app/build.gradle b/app/build.gradle
index 1beaaa4..12aee1f 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -5,7 +5,7 @@ apply plugin: 'kotlin-android-extensions'
 android {
     compileSdkVersion 29
     buildToolsVersion "30.0.3"
-    ndkVersion '21.3.6528147'
+    ndkVersion "21.4.7075529"
 
     compileOptions {
         targetCompatibility JavaVersion.VERSION_1_8
diff --git a/app/libgocryptfs/build.sh b/app/libgocryptfs/build.sh
index 92f854b..9f202a2 100755
--- a/app/libgocryptfs/build.sh
+++ b/app/libgocryptfs/build.sh
@@ -3,7 +3,7 @@
 if [ -z ${ANDROID_NDK_HOME+x} ]; then
   echo "Error: \$ANDROID_NDK_HOME is not defined."
 elif [ -z ${OPENSSL_PATH+x} ]; then
-    echo "Error: \$OPENSSL_PATH is not defined."
+  echo "Error: \$OPENSSL_PATH is not defined."
 else
   NDK_BIN_PATH="$ANDROID_NDK_HOME/toolchains/llvm/prebuilt/linux-x86_64/bin"
   declare -a ABIs=("x86_64" "arm64-v8a" "armeabi-v7a")