diff --git a/src/js_stream.cc b/src/js_stream.cc
index aa8de3a9ad9b8f..16fabc9df3449f 100644
--- a/src/js_stream.cc
+++ b/src/js_stream.cc
@@ -90,7 +90,7 @@ int JSStream::DoWrite(WriteWrap* w,
   Local<Array> bufs_arr = Array::New(env()->isolate(), count);
   Local<Object> buf;
   for (size_t i = 0; i < count; i++) {
-    buf = Buffer::New(env(), bufs[i].base, bufs[i].len).ToLocalChecked();
+    buf = Buffer::Copy(env(), bufs[i].base, bufs[i].len).ToLocalChecked();
     bufs_arr->Set(i, buf);
   }
 
diff --git a/src/node_buffer.cc b/src/node_buffer.cc
index 5ab599ebab93ec..76a733311b0eb0 100644
--- a/src/node_buffer.cc
+++ b/src/node_buffer.cc
@@ -281,13 +281,13 @@ MaybeLocal<Object> Copy(Isolate* isolate, const char* data, size_t length) {
   Environment* env = Environment::GetCurrent(isolate);
   EscapableHandleScope handle_scope(env->isolate());
   Local<Object> obj;
-  if (Buffer::New(env, data, length).ToLocal(&obj))
+  if (Buffer::Copy(env, data, length).ToLocal(&obj))
     return handle_scope.Escape(obj);
   return Local<Object>();
 }
 
 
-MaybeLocal<Object> New(Environment* env, const char* data, size_t length) {
+MaybeLocal<Object> Copy(Environment* env, const char* data, size_t length) {
   EscapableHandleScope scope(env->isolate());
 
   // V8 currently only allows a maximum Typed Array index of max Smi.
@@ -371,7 +371,7 @@ MaybeLocal<Object> New(Isolate* isolate, char* data, size_t length) {
 }
 
 
-MaybeLocal<Object> Use(Environment* env, char* data, size_t length) {
+MaybeLocal<Object> New(Environment* env, char* data, size_t length) {
   EscapableHandleScope scope(env->isolate());
 
   if (length > 0) {
diff --git a/src/node_buffer.h b/src/node_buffer.h
index 5b935b8c063abc..49fb5741640060 100644
--- a/src/node_buffer.h
+++ b/src/node_buffer.h
@@ -4,10 +4,6 @@
 #include "node.h"
 #include "v8.h"
 
-#if defined(NODE_WANT_INTERNALS)
-#include "env.h"
-#endif  // defined(NODE_WANT_INTERNALS)
-
 namespace node {
 namespace Buffer {
 
@@ -63,19 +59,6 @@ static inline bool IsWithinBounds(size_t off, size_t len, size_t max) {
   return true;
 }
 
-// Internal. Not for public consumption. We can't define these
-// in src/node_internals.h because of a circular dependency.
-#if defined(NODE_WANT_INTERNALS)
-v8::MaybeLocal<v8::Object> New(Environment* env, size_t size);
-v8::MaybeLocal<v8::Object> New(Environment* env, const char* data, size_t len);
-v8::MaybeLocal<v8::Object> New(Environment* env,
-                               char* data,
-                               size_t length,
-                               FreeCallback callback,
-                               void* hint);
-v8::MaybeLocal<v8::Object> Use(Environment* env, char* data, size_t length);
-#endif  // defined(NODE_WANT_INTERNALS)
-
 }  // namespace Buffer
 }  // namespace node
 
diff --git a/src/node_crypto.cc b/src/node_crypto.cc
index b5e83f9fa16496..aa0b60ea898a52 100644
--- a/src/node_crypto.cc
+++ b/src/node_crypto.cc
@@ -1021,12 +1021,12 @@ int SecureContext::TicketKeyCallback(SSL* ssl,
   Context::Scope context_scope(env->context());
 
   Local<Value> argv[] = {
-    Buffer::New(env,
-                reinterpret_cast<char*>(name),
-                kTicketPartSize).ToLocalChecked(),
-    Buffer::New(env,
-                reinterpret_cast<char*>(iv),
-                kTicketPartSize).ToLocalChecked(),
+    Buffer::Copy(env,
+                 reinterpret_cast<char*>(name),
+                 kTicketPartSize).ToLocalChecked(),
+    Buffer::Copy(env,
+                 reinterpret_cast<char*>(iv),
+                 kTicketPartSize).ToLocalChecked(),
     Boolean::New(env->isolate(), enc != 0)
   };
   Local<Value> ret = node::MakeCallback(env,
@@ -1219,7 +1219,7 @@ int SSLWrap<Base>::NewSessionCallback(SSL* s, SSL_SESSION* sess) {
   memset(serialized, 0, size);
   i2d_SSL_SESSION(sess, &serialized);
 
-  Local<Object> session = Buffer::New(
+  Local<Object> session = Buffer::Copy(
       env,
       reinterpret_cast<char*>(sess->session_id),
       sess->session_id_length).ToLocalChecked();
@@ -1240,7 +1240,7 @@ void SSLWrap<Base>::OnClientHello(void* arg,
   Context::Scope context_scope(env->context());
 
   Local<Object> hello_obj = Object::New(env->isolate());
-  Local<Object> buff = Buffer::New(
+  Local<Object> buff = Buffer::Copy(
       env,
       reinterpret_cast<const char*>(hello.session_id()),
       hello.session_size()).ToLocalChecked();
@@ -1703,7 +1703,7 @@ void SSLWrap<Base>::GetTLSTicket(const FunctionCallbackInfo<Value>& args) {
   if (sess == nullptr || sess->tlsext_tick == nullptr)
     return;
 
-  Local<Object> buff = Buffer::New(
+  Local<Object> buff = Buffer::Copy(
       env,
       reinterpret_cast<char*>(sess->tlsext_tick),
       sess->tlsext_ticklen).ToLocalChecked();
@@ -1985,7 +1985,7 @@ int SSLWrap<Base>::TLSExtStatusCallback(SSL* s, void* arg) {
     if (resp == nullptr) {
       arg = Null(env->isolate());
     } else {
-      arg = Buffer::New(
+      arg = Buffer::Copy(
           env,
           reinterpret_cast<char*>(const_cast<unsigned char*>(resp)),
           len).ToLocalChecked();
@@ -2991,7 +2991,8 @@ bool CipherBase::GetAuthTag(char** out, unsigned int* out_len) const {
   if (initialised_ || kind_ != kCipher || !auth_tag_)
     return false;
   *out_len = auth_tag_len_;
-  *out = new char[auth_tag_len_];
+  *out = static_cast<char*>(malloc(auth_tag_len_));
+  CHECK_NE(*out, nullptr);
   memcpy(*out, auth_tag_, auth_tag_len_);
   return true;
 }
@@ -3122,8 +3123,9 @@ void CipherBase::Update(const FunctionCallbackInfo<Value>& args) {
                             "Trying to add data in unsupported state");
   }
 
+  CHECK(out != nullptr || out_len == 0);
   Local<Object> buf =
-      Buffer::New(env, reinterpret_cast<char*>(out), out_len).ToLocalChecked();
+      Buffer::Copy(env, reinterpret_cast<char*>(out), out_len).ToLocalChecked();
   if (out)
     delete[] out;
 
@@ -3198,7 +3200,7 @@ void CipherBase::Final(const FunctionCallbackInfo<Value>& args) {
     }
   }
 
-  Local<Object> buf = Buffer::New(
+  Local<Object> buf = Buffer::Copy(
       env,
       reinterpret_cast<char*>(out_value),
       out_len).ToLocalChecked();
@@ -3980,7 +3982,7 @@ void PublicKeyCipher::Cipher(const FunctionCallbackInfo<Value>& args) {
     }
   }
 
-  Local<Object> vbuf = Buffer::New(
+  Local<Object> vbuf = Buffer::Copy(
       env,
       reinterpret_cast<char*>(out_value),
       out_len).ToLocalChecked();
diff --git a/src/node_internals.h b/src/node_internals.h
index c99b2feeb0bdcd..c68b7155b0cdaf 100644
--- a/src/node_internals.h
+++ b/src/node_internals.h
@@ -272,6 +272,21 @@ class NodeInstanceData {
     DISALLOW_COPY_AND_ASSIGN(NodeInstanceData);
 };
 
+namespace Buffer {
+v8::MaybeLocal<v8::Object> Copy(Environment* env, const char* data, size_t len);
+v8::MaybeLocal<v8::Object> New(Environment* env, size_t size);
+// Takes ownership of |data|.
+v8::MaybeLocal<v8::Object> New(Environment* env,
+                               char* data,
+                               size_t length,
+                               void (*callback)(char* data, void* hint),
+                               void* hint);
+// Takes ownership of |data|.  Must allocate |data| with malloc() or realloc()
+// because ArrayBufferAllocator::Free() deallocates it again with free().
+// Mixing operator new and free() is undefined behavior so don't do that.
+v8::MaybeLocal<v8::Object> New(Environment* env, char* data, size_t length);
+}  // namespace Buffer
+
 }  // namespace node
 
 #endif  // SRC_NODE_INTERNALS_H_