From 51cd83f6744ca1546fe6e64187150c60d0acd717 Mon Sep 17 00:00:00 2001
From: BONNAURE Olivier <o.bonnaure@solisoft.net>
Date: Sun, 21 Jan 2024 15:58:48 +0100
Subject: [PATCH] Add Curve25519 method in help.txt + add new specs file
 (#1096)

---
 test/tool/net/curve25519_test.lua | 32 +++++++++++++++++++++++++++++++
 tool/net/help.txt                 | 16 ++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 test/tool/net/curve25519_test.lua

diff --git a/test/tool/net/curve25519_test.lua b/test/tool/net/curve25519_test.lua
new file mode 100644
index 000000000..8573bb913
--- /dev/null
+++ b/test/tool/net/curve25519_test.lua
@@ -0,0 +1,32 @@
+-- Copyright 2022 Justine Alexandra Roberts Tunney
+--
+-- Permission to use, copy, modify, and/or distribute this software for
+-- any purpose with or without fee is hereby granted, provided that the
+-- above copyright notice and this permission notice appear in all copies.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+-- WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+-- WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+-- AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+-- DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+-- PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+-- TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+-- PERFORMANCE OF THIS SOFTWARE.
+
+local secret1 = GetRandomBytes(32)
+local public1 = Curve25519(secret1, "\9")
+local secret2 = GetRandomBytes(32)
+local public2 = Curve25519(secret2, "\9")
+local secret3 = GetRandomBytes(32)
+local public3 = Curve25519(secret3, "\9")
+
+local shared_key1 = Curve25519(secret1, public2)
+local shared_key2 = Curve25519(secret2, public1)
+
+local shared_key3 = Curve25519(secret2, public3)
+local shared_key4 = Curve25519(secret3, public2)
+
+assert(shared_key1 == shared_key2)
+assert(shared_key1 ~= shared_key3)
+assert(shared_key2 ~= shared_key3)
+assert(shared_key4 == shared_key3)
diff --git a/tool/net/help.txt b/tool/net/help.txt
index 595475a53..e238634f9 100644
--- a/tool/net/help.txt
+++ b/tool/net/help.txt
@@ -1137,6 +1137,22 @@ FUNCTIONS
           The name can be one of the following strings: MD5, SHA1, SHA224,
           SHA256, SHA384, SHA512, and BLAKE2B256.
 
+  Curve25519(secret:str, public_or_basepoint:str) -> str
+          Returns the shared key for the specified secret and public values.
+          The second argument can be either a public key or a basepoint, used
+          for generating a shared or public key.
+
+          Here a small usage sample :
+
+            >: secret1 = GetRandomBytes(32)
+            >: public1 = Curve25519(secret1, "\9")
+            >: secret2 = GetRandomBytes(32)
+            >: public2 = Curve25519(secret2, "\9")
+            >: shared_key1 = Curve25519(secret1, public2)
+            >: shared_key2 = Curve25519(secret2, public1)
+            >: shared_key1 == shared_key2
+            true
+
   GetRemoteAddr() → ip:uint32,port:uint16
           Returns client ip4 address and port, e.g. 0x01020304,31337 would
           represent 1.2.3.4:31337. This is the same as GetClientAddr except