change rsa padding schema in GroupManager to OAEP

Change-Id: Idfbe4b89237db9474e7c8d02be080caae1320838
diff --git a/src/group-manager.cpp b/src/group-manager.cpp
index 64a4e8c..345eb79 100644
--- a/src/group-manager.cpp
+++ b/src/group-manager.cpp
@@ -163,7 +163,6 @@
 {
   RandomNumberGenerator rng;
   RsaKeyParams params(m_paramLength);
-  algo::EncryptParams eparams(tlv::AlgorithmRsaPkcs);
   DecryptKey<algo::Rsa> privateKey = algo::Rsa::generateKey(rng, params);
   priKeyBuf = privateKey.getKeyBits();
   EncryptKey<algo::Rsa> publicKey = algo::Rsa::deriveEncryptKey(priKeyBuf);
@@ -194,7 +193,7 @@
   name.append(startTs).append(endTs);
   Data data = Data(name);
   data.setFreshnessPeriod(time::hours(m_freshPeriod));
-  algo::EncryptParams eparams(tlv::AlgorithmRsaPkcs);
+  algo::EncryptParams eparams(tlv::AlgorithmRsaOaep);
   algo::encryptData(data, priKeyBuf.buf(), priKeyBuf.size(), keyName,
                     certKey.buf(), certKey.size(), eparams);
   m_keyChain.sign(data);