diff --git a/ldap-services/src/main/java/de/hsadmin/service/ldap/LdapUserVO.java b/ldap-services/src/main/java/de/hsadmin/service/ldap/LdapUserVO.java
index 912c0e8..a535781 100644
--- a/ldap-services/src/main/java/de/hsadmin/service/ldap/LdapUserVO.java
+++ b/ldap-services/src/main/java/de/hsadmin/service/ldap/LdapUserVO.java
@@ -9,6 +9,7 @@ import de.hsadmin.module.property.ReadWritePolicy;
 import de.hsadmin.module.property.Required;
 import de.hsadmin.module.property.Search;
 import de.hsadmin.module.property.SearchPolicy;
+import de.hsadmin.module.property.StringSet;
 
 public class LdapUserVO extends AbstractVO {
 
@@ -50,7 +51,7 @@ public class LdapUserVO extends AbstractVO {
 	private String nickName;
 
 	@ReadWrite(ReadWritePolicy.READWRITE)
-	private String[] sshPublicKey;
+	private StringSet sshPublicKey;
 	
 	public LdapUserVO() throws TechnicalException {
 		super();
@@ -120,14 +121,12 @@ public class LdapUserVO extends AbstractVO {
 		this.nickName = nickName;
 	}
 
-	public String[] getSshPublicKey() {
+	public StringSet getSshPublicKey() {
 		return sshPublicKey;
 	}
 
-	public void setSshPublicKey(String[] sshPublicKey) {
+	public void setSshPublicKey(StringSet sshPublicKey) {
 		this.sshPublicKey = sshPublicKey;
 	}
 
-
-
 }
diff --git a/ldap-services/src/test/java/de/hsadmin/service/ldap/ValidationTest.java b/ldap-services/src/test/java/de/hsadmin/service/ldap/ValidationTest.java
new file mode 100644
index 0000000..c596f0f
--- /dev/null
+++ b/ldap-services/src/test/java/de/hsadmin/service/ldap/ValidationTest.java
@@ -0,0 +1,82 @@
+package de.hsadmin.service.ldap;
+
+import static org.junit.Assert.*;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import de.hsadmin.common.error.TechnicalException;
+import de.hsadmin.common.error.UserError;
+import de.hsadmin.common.error.UserException;
+import de.hsadmin.module.impl.ValidationDelegate;
+import de.hsadmin.module.property.StringProperty;
+
+public class ValidationTest {
+
+	private LdapUserVO vo;
+	private ValidationDelegate<LdapUserVO> val;
+
+	@Before
+	public void setUp() throws Exception {
+		vo = new LdapUserVO();
+		val = new ValidationDelegate<LdapUserVO>();
+	}
+
+	@After
+	public void tearDown() throws Exception {
+		vo = null;
+	}
+
+	@Test
+	public void testSetUid() {
+		final String uidFail = "ac-someuid";
+		try {
+			((StringProperty) vo.get("uid")).setValue(uidFail);
+			String uid = vo.getUid();
+			assertEquals(uidFail, uid);
+			val.checkPrototypeIsCreateable(vo);
+			fail("expect UserException");
+		} catch (UserException | TechnicalException e) {
+			if (e instanceof UserException) {
+				UserException ue = (UserException) e;
+				assertTrue("expect validationerror " + UserError.MSG_FIELD_DOESNOT_VALIDATE, ue.hasError(UserError.MSG_FIELD_DOESNOT_VALIDATE));
+			} else {
+				fail(e.getMessage());
+			}
+		}
+		final String uidOk = "abc-someuid";
+		final String mailOk = "someone@example.org";
+		final String snOk = "Mustermann";
+		try {
+			((StringProperty) vo.get("uid")).setValue(uidOk);
+			String uid = vo.getUid();
+			assertEquals(uidOk, uid);
+			((StringProperty) vo.get("mail")).setValue(mailOk);
+			String mail = vo.getMail();
+			assertEquals(mailOk, mail);
+			((StringProperty) vo.get("sn")).setValue(snOk);
+			String sn = vo.getSn();
+			assertEquals(snOk, sn);
+			val.checkPrototypeIsCreateable(vo);
+		} catch (UserException | TechnicalException e) {
+			fail(e.getMessage());
+		}
+	}
+
+//	@Test
+	public void testSetMail() {
+		fail("Not yet implemented");
+	}
+
+//	@Test
+	public void testSetMobile() {
+		fail("Not yet implemented");
+	}
+
+//	@Test
+	public void testSetNickName() {
+		fail("Not yet implemented");
+	}
+
+}