From 28edf6bafcfd8c80e2cb52c498db8930f8517fd1 Mon Sep 17 00:00:00 2001
From: Kazuki Yamaguchi <k@rhe.jp>
Date: Sat, 18 Mar 2017 22:34:19 +0900
Subject: pkey: reimplement PKey::DH#compute_key and PKey::EC#dh_compute_key

Use the new OpenSSL::PKey::PKey#derive instead of the raw
{EC,}DH_compute_key(), mainly to reduce amount of the C code.
---
 lib/openssl/pkey.rb | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

(limited to 'lib')

diff --git a/lib/openssl/pkey.rb b/lib/openssl/pkey.rb
index 9cc32763..be60ac2b 100644
--- a/lib/openssl/pkey.rb
+++ b/lib/openssl/pkey.rb
@@ -9,6 +9,24 @@ require_relative 'marshal'
 module OpenSSL::PKey
   class DH
     include OpenSSL::Marshal
+
+    # :call-seq:
+    #    dh.compute_key(pub_bn) -> string
+    #
+    # Returns a String containing a shared secret computed from the other
+    # party's public value.
+    #
+    # This method is provided for backwards compatibility, and calls #derive
+    # internally.
+    #
+    # === Parameters
+    # * _pub_bn_ is a OpenSSL::BN, *not* the DH instance returned by
+    #   DH#public_key as that contains the DH parameters only.
+    def compute_key(pub_bn)
+      peer = dup
+      peer.set_key(pub_bn, nil)
+      derive(peer)
+    end
   end
 
   class DSA
@@ -18,7 +36,22 @@ module OpenSSL::PKey
   if defined?(EC)
   class EC
     include OpenSSL::Marshal
+
+    # :call-seq:
+    #    ec.dh_compute_key(pubkey) -> string
+    #
+    # Derives a shared secret by ECDH. _pubkey_ must be an instance of
+    # OpenSSL::PKey::EC::Point and must belong to the same group.
+    #
+    # This method is provided for backwards compatibility, and calls #derive
+    # internally.
+    def dh_compute_key(pubkey)
+      peer = OpenSSL::PKey::EC.new(group)
+      peer.public_key = pubkey
+      derive(peer)
+    end
   end
+
   class EC::Point
     # :call-seq:
     #    point.to_bn([conversion_form]) -> OpenSSL::BN
-- 
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