diff --git a/src/3rdparty/monocypher/monocypher-ed25519.h b/src/3rdparty/monocypher/monocypher-ed25519.h
new file mode 100644
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+++ b/src/3rdparty/monocypher/monocypher-ed25519.h
@@ -0,0 +1,140 @@
+// Monocypher version 4.0.2
+//
+// This file is dual-licensed.  Choose whichever licence you want from
+// the two licences listed below.
+//
+// The first licence is a regular 2-clause BSD licence.  The second licence
+// is the CC-0 from Creative Commons. It is intended to release Monocypher
+// to the public domain.  The BSD licence serves as a fallback option.
+//
+// SPDX-License-Identifier: BSD-2-Clause OR CC0-1.0
+//
+// ------------------------------------------------------------------------
+//
+// Copyright (c) 2017-2019, Loup Vaillant
+// All rights reserved.
+//
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// 1. Redistributions of source code must retain the above copyright
+//    notice, this list of conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright
+//    notice, this list of conditions and the following disclaimer in the
+//    documentation and/or other materials provided with the
+//    distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// ------------------------------------------------------------------------
+//
+// Written in 2017-2019 by Loup Vaillant
+//
+// To the extent possible under law, the author(s) have dedicated all copyright
+// and related neighboring rights to this software to the public domain
+// worldwide.  This software is distributed without any warranty.
+//
+// You should have received a copy of the CC0 Public Domain Dedication along
+// with this software.  If not, see
+// <https://creativecommons.org/publicdomain/zero/1.0/>
+
+#ifndef ED25519_H
+#define ED25519_H
+
+#include "monocypher.h"
+
+#ifdef MONOCYPHER_CPP_NAMESPACE
+namespace MONOCYPHER_CPP_NAMESPACE {
+#elif defined(__cplusplus)
+extern "C" {
+#endif
+
+////////////////////////
+/// Type definitions ///
+////////////////////////
+
+// Do not rely on the size or content on any of those types,
+// they may change without notice.
+typedef struct {
+	uint64_t hash[8];
+	uint64_t input[16];
+	uint64_t input_size[2];
+	size_t   input_idx;
+} crypto_sha512_ctx;
+
+typedef struct {
+	uint8_t key[128];
+	crypto_sha512_ctx ctx;
+} crypto_sha512_hmac_ctx;
+
+
+// SHA 512
+// -------
+void crypto_sha512_init  (crypto_sha512_ctx *ctx);
+void crypto_sha512_update(crypto_sha512_ctx *ctx,
+                          const uint8_t *message, size_t  message_size);
+void crypto_sha512_final (crypto_sha512_ctx *ctx, uint8_t hash[64]);
+void crypto_sha512(uint8_t hash[64],
+                   const uint8_t *message, size_t message_size);
+
+// SHA 512 HMAC
+// ------------
+void crypto_sha512_hmac_init(crypto_sha512_hmac_ctx *ctx,
+                             const uint8_t *key, size_t key_size);
+void crypto_sha512_hmac_update(crypto_sha512_hmac_ctx *ctx,
+                               const uint8_t *message, size_t  message_size);
+void crypto_sha512_hmac_final(crypto_sha512_hmac_ctx *ctx, uint8_t hmac[64]);
+void crypto_sha512_hmac(uint8_t hmac[64],
+                        const uint8_t *key    , size_t key_size,
+                        const uint8_t *message, size_t message_size);
+
+// SHA 512 HKDF
+// ------------
+void crypto_sha512_hkdf_expand(uint8_t       *okm,  size_t okm_size,
+                               const uint8_t *prk,  size_t prk_size,
+                               const uint8_t *info, size_t info_size);
+void crypto_sha512_hkdf(uint8_t       *okm , size_t okm_size,
+                        const uint8_t *ikm , size_t ikm_size,
+                        const uint8_t *salt, size_t salt_size,
+                        const uint8_t *info, size_t info_size);
+
+// Ed25519
+// -------
+// Signatures (EdDSA with curve25519 + SHA-512)
+// --------------------------------------------
+void crypto_ed25519_key_pair(uint8_t secret_key[64],
+                             uint8_t public_key[32],
+                             uint8_t seed[32]);
+void crypto_ed25519_sign(uint8_t        signature [64],
+                         const uint8_t  secret_key[64],
+                         const uint8_t *message, size_t message_size);
+int crypto_ed25519_check(const uint8_t  signature [64],
+                         const uint8_t  public_key[32],
+                         const uint8_t *message, size_t message_size);
+
+// Pre-hash variants
+void crypto_ed25519_ph_sign(uint8_t       signature   [64],
+                            const uint8_t secret_key  [64],
+                            const uint8_t message_hash[64]);
+int crypto_ed25519_ph_check(const uint8_t signature   [64],
+                            const uint8_t public_key  [32],
+                            const uint8_t message_hash[64]);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // ED25519_H