diff --git a/include/fc/optional.hpp b/include/fc/optional.hpp
index 04145b4..f79b7dc 100644
--- a/include/fc/optional.hpp
+++ b/include/fc/optional.hpp
@@ -1,6 +1,8 @@
 #pragma once
 #include <assert.h>
 #include <utility>
+#include <string.h>
+
 
 namespace fc {
 #ifdef _MSC_VER
@@ -22,12 +24,13 @@ namespace fc {
     public:
       typedef T value_type;
 
-      optional():_valid(false){}
+      optional():_valid(false){ memset(_value, 0, sizeof(_value)); }
       ~optional(){ reset(); }
 
       optional( optional& o )
       :_valid(false) 
       {
+        memset(_value, 0, sizeof(_value));
         if( o._valid ) new (ptr()) T( *o );
         _valid = o._valid;
       }
@@ -35,6 +38,7 @@ namespace fc {
       optional( const optional& o )
       :_valid(false) 
       {
+        memset(_value, 0, sizeof(_value));
         if( o._valid ) new (ptr()) T( *o );
         _valid = o._valid;
       }
@@ -42,6 +46,7 @@ namespace fc {
       optional( optional&& o )
       :_valid(false) 
       {
+        memset(_value, 0, sizeof(_value));
         if( o._valid ) new (ptr()) T( std::move(*o) );
         _valid = o._valid;
         o.reset();
@@ -51,6 +56,7 @@ namespace fc {
       optional( const optional<U>& o )
       :_valid(false) 
       {
+        memset(_value, 0, sizeof(_value));
         if( o._valid ) new (ptr()) T( *o );
         _valid = o._valid;
       }
@@ -59,6 +65,7 @@ namespace fc {
       optional( optional<U>& o )
       :_valid(false) 
       {
+        memset(_value, 0, sizeof(_value));
         if( o._valid )
         {
           new (ptr()) T( *o );
@@ -70,6 +77,7 @@ namespace fc {
       optional( optional<U>&& o )
       :_valid(false) 
       {
+        memset(_value, 0, sizeof(_value));
         if( o._valid ) new (ptr()) T( std::move(*o) );
         _valid = o._valid;
         o.reset();
@@ -79,6 +87,7 @@ namespace fc {
       optional( U&& u )
       :_valid(true) 
       {
+        memset(_value, 0, sizeof(_value));
         new ((char*)ptr()) T( std::forward<U>(u) );
       }
 
diff --git a/src/compress/miniz.c b/src/compress/miniz.c
index 987614d..f794c93 100644
--- a/src/compress/miniz.c
+++ b/src/compress/miniz.c
@@ -1497,7 +1497,10 @@ tinfl_status tinfl_decompress(tinfl_decompressor *r, const mz_uint8 *pIn_buf_nex
       {
         mz_uint8 *p = r->m_tables[0].m_code_size; mz_uint i;
         r->m_table_sizes[0] = 288; r->m_table_sizes[1] = 32; TINFL_MEMSET(r->m_tables[1].m_code_size, 5, 32);
-        for (i = 0; i <= 143; ++i) {*p++ = 8;} for (; i <= 255; ++i) {*p++ = 9;} for (; i <= 279; ++i) {*p++ = 7;} for (; i <= 287; ++i) {*p++ = 8;}
+        for ( i = 0; i <= 143; ++i) *p++ = 8;
+        for ( ; i <= 255; ++i) *p++ = 9;
+        for ( ; i <= 279; ++i) *p++ = 7;
+        for ( ; i <= 287; ++i) *p++ = 8;
       }
       else
       {
@@ -2281,7 +2284,11 @@ static MZ_FORCEINLINE void tdefl_find_match(tdefl_compressor *d, mz_uint lookahe
         if (TDEFL_READ_UNALIGNED_WORD(&d->m_dict[probe_pos + match_len - 1]) == c01) break;
       TDEFL_PROBE; TDEFL_PROBE; TDEFL_PROBE;
     }
-    if (!dist) {break;} q = (const mz_uint16*)(d->m_dict + probe_pos); if (TDEFL_READ_UNALIGNED_WORD(q) != s01) {continue;} p = s; probe_len = 32;
+    if (!dist) break;
+    q = (const mz_uint16*)(d->m_dict + probe_pos);
+    if (TDEFL_READ_UNALIGNED_WORD(q) != s01) continue;
+    p = s;
+    probe_len = 32;
     do { } while ( (TDEFL_READ_UNALIGNED_WORD(++p) == TDEFL_READ_UNALIGNED_WORD(++q)) && (TDEFL_READ_UNALIGNED_WORD(++p) == TDEFL_READ_UNALIGNED_WORD(++q)) &&
                    (TDEFL_READ_UNALIGNED_WORD(++p) == TDEFL_READ_UNALIGNED_WORD(++q)) && (TDEFL_READ_UNALIGNED_WORD(++p) == TDEFL_READ_UNALIGNED_WORD(++q)) && (--probe_len > 0) );
     if (!probe_len)
diff --git a/src/crypto/aes.cpp b/src/crypto/aes.cpp
index 55464a7..d675cc3 100644
--- a/src/crypto/aes.cpp
+++ b/src/crypto/aes.cpp
@@ -75,7 +75,9 @@ uint32_t aes_encoder::encode( const char* plaintxt, uint32_t plaintext_len, char
         FC_THROW_EXCEPTION( aes_exception, "error during aes 256 cbc encryption update", 
                            ("s", ERR_error_string( ERR_get_error(), nullptr) ) );
     }
-    FC_ASSERT( (uint32_t) ciphertext_len == plaintext_len, "", ("ciphertext_len",ciphertext_len)("plaintext_len",plaintext_len) );
+    int64_t ciphertext_len_i64 = ciphertext_len;
+    int64_t plaintext_len_i64 = plaintext_len;
+    FC_ASSERT( ciphertext_len_i64 == plaintext_len_i64, "", ("ciphertext_len",ciphertext_len)("plaintext_len",plaintext_len) );
     return ciphertext_len;
 }
 #if 0
@@ -146,7 +148,9 @@ uint32_t aes_decoder::decode( const char* ciphertxt, uint32_t ciphertxt_len, cha
         FC_THROW_EXCEPTION( aes_exception, "error during aes 256 cbc decryption update", 
                            ("s", ERR_error_string( ERR_get_error(), nullptr) ) );
     }
-    FC_ASSERT( ciphertxt_len == (uint32_t)plaintext_len, "", ("ciphertxt_len",ciphertxt_len)("plaintext_len",plaintext_len) );
+    int64_t ciphertxt_len_i64 = ciphertxt_len;
+    int64_t plaintext_len_i64 = plaintext_len;
+    FC_ASSERT( ciphertxt_len_i64 == plaintext_len_i64, "", ("ciphertxt_len",ciphertxt_len)("plaintext_len",plaintext_len) );
 	return plaintext_len;
 }
 #if 0
diff --git a/src/crypto/elliptic_common.cpp b/src/crypto/elliptic_common.cpp
index dc617c5..7e21bbd 100644
--- a/src/crypto/elliptic_common.cpp
+++ b/src/crypto/elliptic_common.cpp
@@ -83,8 +83,10 @@ namespace fc { namespace ecc {
             ssl_bignum order;
             FC_ASSERT( EC_GROUP_get_order( group, order, ctx ) );
             private_key_secret bin;
-            FC_ASSERT( (size_t) BN_num_bytes( order ) == bin.data_size() );
-            FC_ASSERT( (size_t) BN_bn2bin( order, (unsigned char*) bin.data() ) == bin.data_size() );
+            size_t order_BN_num_bytes = BN_num_bytes( order );
+            FC_ASSERT( order_BN_num_bytes == bin.data_size() );
+            size_t order_BN_bn2bin = BN_bn2bin( order, (unsigned char*) bin.data() );
+            FC_ASSERT( order_BN_bn2bin == bin.data_size() );
             return bin;
         }
 
@@ -102,8 +104,10 @@ namespace fc { namespace ecc {
             FC_ASSERT( EC_GROUP_get_order( group, order, ctx ) );
             BN_rshift1( order, order );
             private_key_secret bin;
-            FC_ASSERT( (size_t) BN_num_bytes( order ) == bin.data_size() );
-            FC_ASSERT( (size_t) BN_bn2bin( order, (unsigned char*) bin.data() ) == bin.data_size() );
+            size_t order_BN_num_bytes = BN_num_bytes( order );
+            FC_ASSERT( order_BN_num_bytes == bin.data_size() );
+            size_t order_BN_bn2bin = BN_bn2bin( order, (unsigned char*) bin.data() );
+            FC_ASSERT( order_BN_bn2bin == bin.data_size() );
             return bin;
         }
 
diff --git a/src/crypto/ripemd160.cpp b/src/crypto/ripemd160.cpp
index fe6c588..6838768 100644
--- a/src/crypto/ripemd160.cpp
+++ b/src/crypto/ripemd160.cpp
@@ -106,7 +106,9 @@ bool operator == ( const ripemd160& h1, const ripemd160& h2 ) {
    void from_variant( const variant& v, ripemd160& bi, uint32_t max_depth )
    {
       std::vector<char> ve = v.as< std::vector<char> >( max_depth );
-      memset( &bi, char(0), sizeof(bi) );
+      for (size_t i = 0; i < bi.data_size(); i++) {
+         bi.data()[i] = 0;
+      }
       if( ve.size() )
          memcpy( &bi, ve.data(), std::min<size_t>(ve.size(),sizeof(bi)) );
   }
diff --git a/src/crypto/sha1.cpp b/src/crypto/sha1.cpp
index d8337e5..49ad65f 100644
--- a/src/crypto/sha1.cpp
+++ b/src/crypto/sha1.cpp
@@ -90,7 +90,9 @@ bool operator == ( const sha1& h1, const sha1& h2 ) {
   void from_variant( const variant& v, sha1& bi, uint32_t max_depth )
   {
     std::vector<char> ve = v.as< std::vector<char> >( max_depth );
-    memset( &bi, char(0), sizeof(bi) );
+    for (size_t i = 0; i < bi.data_size(); i++) {
+       bi.data()[i] = 0;
+    }
     if( ve.size() )
        memcpy( &bi, ve.data(), std::min<size_t>(ve.size(),sizeof(bi)) );
   }
diff --git a/src/crypto/sha224.cpp b/src/crypto/sha224.cpp
index 54be117..d371963 100644
--- a/src/crypto/sha224.cpp
+++ b/src/crypto/sha224.cpp
@@ -86,7 +86,9 @@ namespace fc {
    void from_variant( const variant& v, sha224& bi, uint32_t max_depth )
    {
       std::vector<char> ve = v.as< std::vector<char> >( max_depth );
-      memset( &bi, char(0), sizeof(bi) );
+      for (size_t i = 0; i < bi.data_size(); i++) {
+         bi.data()[i] = 0;
+      }
       if( ve.size() )
          memcpy( &bi, ve.data(), std::min<size_t>(ve.size(),sizeof(bi)) );
   }
diff --git a/src/crypto/sha256.cpp b/src/crypto/sha256.cpp
index 6d35035..246f5e0 100644
--- a/src/crypto/sha256.cpp
+++ b/src/crypto/sha256.cpp
@@ -106,7 +106,9 @@ namespace fc {
    void from_variant( const variant& v, sha256& bi, uint32_t max_depth )
    {
       std::vector<char> ve = v.as< std::vector<char> >( max_depth );
-      memset( &bi, char(0), sizeof(bi) );
+      for (size_t i = 0; i < bi.data_size(); i++) {
+         bi.data()[i] = 0;
+      }
       if( ve.size() )
          memcpy( &bi, ve.data(), std::min<size_t>(ve.size(),sizeof(bi)) );
   }
diff --git a/src/crypto/sha512.cpp b/src/crypto/sha512.cpp
index d499314..2c44060 100644
--- a/src/crypto/sha512.cpp
+++ b/src/crypto/sha512.cpp
@@ -92,7 +92,9 @@ namespace fc {
    void from_variant( const variant& v, sha512& bi, uint32_t max_depth )
    {
       std::vector<char> ve = v.as< std::vector<char> >( max_depth );
-      memset( &bi, char(0), sizeof(bi) );
+      for (size_t i = 0; i < bi.data_size(); i++) {
+         bi.data()[i] = 0;
+      }
       if( ve.size() )
          memcpy( &bi, ve.data(), std::min<size_t>(ve.size(),sizeof(bi)) );
   }