diff --git a/src/addrman.cpp b/src/addrman.cpp
index 79545e13c..359ff75e5 100644
--- a/src/addrman.cpp
+++ b/src/addrman.cpp
@@ -9,30 +9,30 @@
 
 using namespace std;
 
-int CAddrInfo::GetTriedBucket(const std::vector<unsigned char> &nKey) const
+int CAddrInfo::GetTriedBucket(const uint256& nKey) const
 {
     CDataStream ss1(SER_GETHASH, 0);
     std::vector<unsigned char> vchKey = GetKey();
-    ss1 << nKey << vchKey;
+    ss1 << ((unsigned char)32) << nKey << vchKey;
     uint64_t hash1 = Hash(ss1.begin(), ss1.end()).GetLow64();
 
     CDataStream ss2(SER_GETHASH, 0);
     std::vector<unsigned char> vchGroupKey = GetGroup();
-    ss2 << nKey << vchGroupKey << (hash1 % ADDRMAN_TRIED_BUCKETS_PER_GROUP);
+    ss2 << ((unsigned char)32) << nKey << vchGroupKey << (hash1 % ADDRMAN_TRIED_BUCKETS_PER_GROUP);
     uint64_t hash2 = Hash(ss2.begin(), ss2.end()).GetLow64();
     return hash2 % ADDRMAN_TRIED_BUCKET_COUNT;
 }
 
-int CAddrInfo::GetNewBucket(const std::vector<unsigned char> &nKey, const CNetAddr& src) const
+int CAddrInfo::GetNewBucket(const uint256& nKey, const CNetAddr& src) const
 {
     CDataStream ss1(SER_GETHASH, 0);
     std::vector<unsigned char> vchGroupKey = GetGroup();
     std::vector<unsigned char> vchSourceGroupKey = src.GetGroup();
-    ss1 << nKey << vchGroupKey << vchSourceGroupKey;
+    ss1 << ((unsigned char)32) << nKey << vchGroupKey << vchSourceGroupKey;
     uint64_t hash1 = Hash(ss1.begin(), ss1.end()).GetLow64();
 
     CDataStream ss2(SER_GETHASH, 0);
-    ss2 << nKey << vchSourceGroupKey << (hash1 % ADDRMAN_NEW_BUCKETS_PER_SOURCE_GROUP);
+    ss2 << ((unsigned char)32) << nKey << vchSourceGroupKey << (hash1 % ADDRMAN_NEW_BUCKETS_PER_SOURCE_GROUP);
     uint64_t hash2 = Hash(ss2.begin(), ss2.end()).GetLow64();
     return hash2 % ADDRMAN_NEW_BUCKET_COUNT;
 }
@@ -486,6 +486,8 @@ int CAddrMan::Check_()
 
     if (setTried.size()) return -13;
     if (mapNew.size()) return -15;
+    if (nKey.IsNull())
+        return -16;
 
     return 0;
 }
diff --git a/src/addrman.h b/src/addrman.h
index 085e8bc9d..f5cdfd7c6 100644
--- a/src/addrman.h
+++ b/src/addrman.h
@@ -8,6 +8,7 @@
 #include "netbase.h"
 #include "protocol.h"
 #include "sync.h"
+#include "uint256.h"
 #include "util.h"
 
 #include <map>
@@ -75,13 +76,13 @@ public:
     }
 
     // Calculate in which "tried" bucket this entry belongs
-    int GetTriedBucket(const std::vector<unsigned char> &nKey) const;
+    int GetTriedBucket(const uint256 &nKey) const;
 
     // Calculate in which "new" bucket this entry belongs, given a certain source
-    int GetNewBucket(const std::vector<unsigned char> &nKey, const CNetAddr& src) const;
+    int GetNewBucket(const uint256 &nKey, const CNetAddr& src) const;
 
     // Calculate in which "new" bucket this entry belongs, using its default source
-    int GetNewBucket(const std::vector<unsigned char> &nKey) const
+    int GetNewBucket(const uint256 &nKey) const
     {
         return GetNewBucket(nKey, source);
     }
@@ -170,7 +171,7 @@ private:
     mutable CCriticalSection cs;
 
     // secret key to randomize bucket select with
-    std::vector<unsigned char> nKey;
+    uint256 nKey;
 
     // last used nId
     int nIdCount;
@@ -275,6 +276,7 @@ public:
 
         unsigned char nVersion = 0;
         s << nVersion;
+        s << ((unsigned char)32);
         s << nKey;
         s << nNew;
         s << nTried;
@@ -319,6 +321,9 @@ public:
 
         unsigned char nVersion;
         s >> nVersion;
+        unsigned char nKeySize;
+        s >> nKeySize;
+        if (nKeySize != 32) throw std::ios_base::failure("Incorrect keysize in addrman");
         s >> nKey;
         s >> nNew;
         s >> nTried;
@@ -384,16 +389,20 @@ public:
 
     CAddrMan() : vRandom(0), vvTried(ADDRMAN_TRIED_BUCKET_COUNT, std::vector<int>(0)), vvNew(ADDRMAN_NEW_BUCKET_COUNT, std::set<int>())
     {
-         nKey.resize(32);
-         RAND_bytes(&nKey[0], 32);
+         RAND_bytes((unsigned char *)&nKey, 32);
 
          nIdCount = 0;
          nTried = 0;
          nNew = 0;
     }
 
+    ~CAddrMan()
+    {
+        nKey = uint256(0);
+    }
+
     // Return the number of (unique) addresses in all tables.
-    int size()
+   int size()
     {
         return vRandom.size();
     }