make CBase58Data class use zero_after_free_allocator

- this way there is no need for an explicit destructor, who does the same
  thing anyway

src/base58.h

@@ -17,11 +17,11 @@
 
 #include <string>
 #include <vector>
-#include <openssl/crypto.h> // for OPENSSL_cleanse()
 
 #include "bignum.h"
 #include "key.h"
 #include "script.h"
+#include "allocators.h"
 
 static const char* pszBase58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
 
@@ -180,7 +180,8 @@ protected:
     unsigned char nVersion;
 
     // the actually encoded data
-    std::vector<unsigned char> vchData;
+    typedef std::vector<unsigned char, zero_after_free_allocator<unsigned char> > vector_uchar;
+    vector_uchar vchData;
 
     CBase58Data()
     {
@@ -188,13 +189,6 @@ protected:
         vchData.clear();
     }
 
-    ~CBase58Data()
-    {
-        // zero the memory, as it may contain sensitive data
-        if (!vchData.empty())
-            OPENSSL_cleanse(&vchData[0], vchData.size());
-    }
-
     void SetData(int nVersionIn, const void* pdata, size_t nSize)
     {
         nVersion = nVersionIn;
@@ -459,4 +453,4 @@ public:
     }
 };
 
-#endif
+#endif // BITCOIN_BASE58_H