added explicit zero out for temporary utf8 password - relates to github #2143

Author: dghgit

prov/src/main/java/org/bouncycastle/jcajce/provider/keystore/pkcs12/PKCS12KeyStoreSpi.java

@@ -2078,6 +2078,8 @@ private byte[] calculatePbeMac(
 
                 CipherParameters key = generator.generateDerivedParameters(BigIntegers.intValueExact(pbkdf2Params.getKeyLength()) * 8);
 
+                Arrays.clear(generator.getPassword());
+
                 hMac.init(key);
                 hMac.update(data, 0, data.length);
                 byte[] res = new byte[hMac.getMacSize()];