Use RSAPublicKey interface instead of OpenSSLRsaPublicKey to avoid conscrypt version conflicts

OpenSSLRsaPublicKey has a different package when using the open-source conscrypt vs. the one inserted
by Play Services.

Signed-off-by: Álvaro Brey <alvaro.brey@nextcloud.com>

app/src/androidTest/java/com/nextcloud/client/EndToEndRandomIT.java

@@ -53,7 +53,6 @@ import com.owncloud.android.utils.EncryptionUtils;
 import com.owncloud.android.utils.FileStorageUtils;
 
 import org.bouncycastle.operator.OperatorCreationException;
-import org.conscrypt.OpenSSLRSAPublicKey;
 import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.Rule;
@@ -67,6 +66,7 @@ import java.security.KeyPair;
 import java.security.NoSuchAlgorithmException;
 import java.security.cert.CertificateException;
 import java.security.interfaces.RSAPrivateCrtKey;
+import java.security.interfaces.RSAPublicKey;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Random;
@@ -502,7 +502,7 @@ public class EndToEndRandomIT extends AbstractOnServerIT {
 
         // check key
         RSAPrivateCrtKey privateKey = (RSAPrivateCrtKey) keyPair.getPrivate();
-        OpenSSLRSAPublicKey publicKey = EncryptionUtils.convertPublicKeyFromString(publicKeyString);
+        RSAPublicKey publicKey = EncryptionUtils.convertPublicKeyFromString(publicKeyString);
 
         BigInteger modulusPublic = publicKey.getModulus();
         BigInteger modulusPrivate = privateKey.getModulus();
@@ -615,7 +615,7 @@ public class EndToEndRandomIT extends AbstractOnServerIT {
 
             // check key
             RSAPrivateCrtKey privateKey = (RSAPrivateCrtKey) keyPair.getPrivate();
-            OpenSSLRSAPublicKey publicKey = EncryptionUtils.convertPublicKeyFromString(publicKeyString);
+            RSAPublicKey publicKey = EncryptionUtils.convertPublicKeyFromString(publicKeyString);
 
             BigInteger modulusPublic = publicKey.getModulus();
             BigInteger modulusPrivate = privateKey.getModulus();

app/src/androidTest/java/com/owncloud/android/util/EncryptionTestIT.java

@@ -36,7 +36,6 @@ import com.owncloud.android.utils.EncryptionUtils;
 
 import org.apache.commons.codec.binary.Hex;
 import org.apache.commons.io.FileUtils;
-import org.conscrypt.OpenSSLRSAPublicKey;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -53,6 +52,7 @@ import java.security.MessageDigest;
 import java.security.PrivateKey;
 import java.security.SecureRandom;
 import java.security.interfaces.RSAPrivateCrtKey;
+import java.security.interfaces.RSAPublicKey;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -184,7 +184,7 @@ public class EncryptionTestIT {
     @Test
     public void testModulus() throws Exception {
         KeyPair keyPair = EncryptionUtils.generateKeyPair();
-        OpenSSLRSAPublicKey publicKey = (OpenSSLRSAPublicKey) keyPair.getPublic();
+        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
         RSAPrivateCrtKey privateKey = (RSAPrivateCrtKey) keyPair.getPrivate();
 
         BigInteger modulusPublic = publicKey.getModulus();

app/src/main/java/com/owncloud/android/utils/EncryptionUtils.java

@@ -46,7 +46,6 @@ import com.owncloud.android.lib.resources.e2ee.UpdateMetadataRemoteOperation;
 import com.owncloud.android.operations.UploadException;
 
 import org.apache.commons.httpclient.HttpStatus;
-import org.conscrypt.OpenSSLRSAPublicKey;
 
 import java.io.BufferedReader;
 import java.io.ByteArrayInputStream;
@@ -72,6 +71,7 @@ import java.security.cert.CertificateException;
 import java.security.cert.CertificateFactory;
 import java.security.cert.X509Certificate;
 import java.security.interfaces.RSAPrivateCrtKey;
+import java.security.interfaces.RSAPublicKey;
 import java.security.spec.InvalidKeySpecException;
 import java.security.spec.KeySpec;
 import java.security.spec.PKCS8EncodedKeySpec;
@@ -855,7 +855,7 @@ public final class EncryptionUtils {
         }
     }
 
-    public static OpenSSLRSAPublicKey convertPublicKeyFromString(String string) throws CertificateException {
+    public static RSAPublicKey convertPublicKeyFromString(String string) throws CertificateException {
         String trimmedCert = string.replace("-----BEGIN CERTIFICATE-----\n", "")
             .replace("-----END CERTIFICATE-----\n", "");
         byte[] encodedCert = trimmedCert.getBytes(StandardCharsets.UTF_8);
@@ -864,7 +864,7 @@ public final class EncryptionUtils {
         CertificateFactory certFactory = CertificateFactory.getInstance("X.509");
         InputStream in = new ByteArrayInputStream(decodedCert);
         X509Certificate certificate = (X509Certificate) certFactory.generateCertificate(in);
-        return (OpenSSLRSAPublicKey) certificate.getPublicKey();
+        return (RSAPublicKey) certificate.getPublicKey();
     }
 
     public static void removeE2E(ArbitraryDataProvider arbitraryDataProvider, User user) {
@@ -877,7 +877,7 @@ public final class EncryptionUtils {
     public static boolean isMatchingKeys(KeyPair keyPair, String publicKeyString) throws CertificateException {
         // check key
         RSAPrivateCrtKey privateKey = (RSAPrivateCrtKey) keyPair.getPrivate();
-        OpenSSLRSAPublicKey publicKey = EncryptionUtils.convertPublicKeyFromString(publicKeyString);
+        RSAPublicKey publicKey = EncryptionUtils.convertPublicKeyFromString(publicKeyString);
 
         BigInteger modulusPublic = publicKey.getModulus();
         BigInteger modulusPrivate = privateKey.getModulus();