1 files changed, 72 insertions, 0 deletions
diff --git a/app/src/main/java/se/leap/bitmaskclient/base/utils/RSAHelper.java b/app/src/main/java/se/leap/bitmaskclient/base/utils/RSAHelper.java
new file mode 100644
index 00000000..2872139a
--- /dev/null
+++ b/app/src/main/java/se/leap/bitmaskclient/base/utils/RSAHelper.java
@@ -0,0 +1,72 @@
+package se.leap.bitmaskclient.base.utils;
+
+import android.os.Build;
+
+import androidx.annotation.VisibleForTesting;
+
+import org.spongycastle.util.encoders.Base64;
+
+import java.security.KeyFactory;
+import java.security.NoSuchAlgorithmException;
+import java.security.NoSuchProviderException;
+import java.security.interfaces.RSAPrivateKey;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.PKCS8EncodedKeySpec;
+
+import de.blinkt.openvpn.core.NativeUtils;
+
+public class RSAHelper {
+
+    public interface RSAHelperInterface {
+        RSAPrivateKey parseRsaKeyFromString(String rsaKeyString);
+    }
+
+    public static class DefaultRSAHelper implements RSAHelperInterface {
+
+        @Override
+        public RSAPrivateKey parseRsaKeyFromString(String rsaKeyString) {
+            RSAPrivateKey key;
+            try {
+                KeyFactory kf;
+                if (Build.VERSION.SDK_INT < Build.VERSION_CODES.P) {
+                    kf = KeyFactory.getInstance("RSA", "BC");
+                } else {
+                    kf = KeyFactory.getInstance("RSA");
+                }
+                rsaKeyString = rsaKeyString.replaceFirst("-----BEGIN RSA PRIVATE KEY-----", "").replaceFirst("-----END RSA PRIVATE KEY-----", "");
+                PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(Base64.decode(rsaKeyString));
+                key = (RSAPrivateKey) kf.generatePrivate(keySpec);
+            } catch (InvalidKeySpecException e) {
+                // TODO Auto-generated catch block
+                e.printStackTrace();
+                return null;
+            } catch (NoSuchAlgorithmException e) {
+                // TODO Auto-generated catch block
+                e.printStackTrace();
+                return null;
+            } catch (NullPointerException e) {
+                e.printStackTrace();
+                return null;
+            } catch (NoSuchProviderException e) {
+                e.printStackTrace();
+                return null;
+            }
+
+            return key;
+        }
+    }
+
+    private static RSAHelperInterface instance = new DefaultRSAHelper();
+
+    @VisibleForTesting
+    public RSAHelper(RSAHelperInterface helperInterface) {
+        if (!NativeUtils.isUnitTest()) {
+            throw new IllegalStateException("RSAHelper injected with RSAHelperInterface outside of an unit test");
+        }
+        instance = helperInterface;
+    }
+
+    public static RSAPrivateKey parseRsaKeyFromString(String rsaKeyString) {
+       return instance.parseRsaKeyFromString(rsaKeyString);
+    }
+}