diff --git a/pom.xml b/pom.xml
index 62a1fe0beac786c99a0f9c8edac6c2202544983c..d2001103751f233cbad654adff1d5ffd5eb2a27b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -2328,7 +2328,7 @@
 		<dependency>
 			<groupId>com.thoughtworks.xstream</groupId>
 			<artifactId>xstream</artifactId>
-			<version>1.4.10</version>
+			<version>1.4.11.1</version>
 		</dependency>
 		<dependency>
 			<groupId>xerces</groupId>
diff --git a/src/main/java/org/olat/core/util/StringHelper.java b/src/main/java/org/olat/core/util/StringHelper.java
index 63210e5d4b3eaeef5d8dacbd5a7856a57d3993be..26a0da6aab0189a85e23e7ee3f94e427b1fd8716 100644
--- a/src/main/java/org/olat/core/util/StringHelper.java
+++ b/src/main/java/org/olat/core/util/StringHelper.java
@@ -211,7 +211,7 @@ public class StringHelper {
 	 * @return The encoded string
 	 */
 	public static String encodeBase64(String unencoded) {
-		return new Base64Encoder().encode(unencoded.getBytes());
+		return new Base64Encoder(true).encode(unencoded.getBytes());
 	}
 	
 	/**
@@ -221,7 +221,7 @@ public class StringHelper {
 	 * @return The encoded string
 	 */
 	public static String encodeBase64(byte[] unencoded) {
-		return new Base64Encoder().encode(unencoded);
+		return new Base64Encoder(true).encode(unencoded);
 	}
 	
 	/**
@@ -231,7 +231,7 @@ public class StringHelper {
 	 * @return The decoded string
 	 */
 	public static String decodeBase64(String encoded) {
-		byte[] decoded = new Base64Encoder().decode(encoded);
+		byte[] decoded = new Base64Encoder(true).decode(encoded);
 		return new String(decoded);
 	}
 
diff --git a/src/test/java/org/olat/core/util/StringHelperTest.java b/src/test/java/org/olat/core/util/StringHelperTest.java
index 5f71eddda9668371c82f452eec410ec122be2f03..61185ec8372bdedf1e3d4cbc16b61c2d76d3b566 100644
--- a/src/test/java/org/olat/core/util/StringHelperTest.java
+++ b/src/test/java/org/olat/core/util/StringHelperTest.java
@@ -43,7 +43,7 @@ public class StringHelperTest {
 	public void base64() throws Exception {
 		String str = "this a super secret string avec un \u00E9 et encore quelques charact\u00E8res kanji \u30b0.";
 
-		String xstream64 = new com.thoughtworks.xstream.core.util.Base64Encoder().encode(str.getBytes());
+		String xstream64 = new com.thoughtworks.xstream.core.util.Base64Encoder(true).encode(str.getBytes());
 		String infinispan64 = org.infinispan.commons.util.Base64.encodeBytes(str.getBytes());
 		String olat64 = StringHelper.encodeBase64(str);
 		String olatBytes64 = StringHelper.encodeBase64(str.getBytes());
@@ -54,15 +54,15 @@ public class StringHelperTest {
 		
 		//decode with the same coder
 		Assert.assertEquals(str, new String(org.infinispan.commons.util.Base64.decode(infinispan64)));
-		Assert.assertEquals(str, new String(new com.thoughtworks.xstream.core.util.Base64Encoder().decode(xstream64)));
+		Assert.assertEquals(str, new String(new com.thoughtworks.xstream.core.util.Base64Encoder(true).decode(xstream64)));
 		Assert.assertEquals(str, StringHelper.decodeBase64(olat64));
 		Assert.assertEquals(str, StringHelper.decodeBase64(olatBytes64));
 		
 		//decode with an other decoder
 		Assert.assertEquals(str, new String(org.infinispan.commons.util.Base64.decode(olat64)));
 		Assert.assertEquals(str, new String(org.infinispan.commons.util.Base64.decode(olatBytes64)));
-		Assert.assertEquals(str, new String(new com.thoughtworks.xstream.core.util.Base64Encoder().decode(olat64)));
-		Assert.assertEquals(str, new String(new com.thoughtworks.xstream.core.util.Base64Encoder().decode(olatBytes64)));
+		Assert.assertEquals(str, new String(new com.thoughtworks.xstream.core.util.Base64Encoder(true).decode(olat64)));
+		Assert.assertEquals(str, new String(new com.thoughtworks.xstream.core.util.Base64Encoder(true).decode(olatBytes64)));
 		Assert.assertEquals(str, StringHelper.decodeBase64(infinispan64));
 		Assert.assertEquals(str, StringHelper.decodeBase64(xstream64));
 	}