--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/include/mupdf/helpers/pkcs7-openssl.h	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,48 @@
+// Copyright (C) 2004-2021 Artifex Software, Inc.
+//
+// This file is part of MuPDF.
+//
+// MuPDF is free software: you can redistribute it and/or modify it under the
+// terms of the GNU Affero General Public License as published by the Free
+// Software Foundation, either version 3 of the License, or (at your option)
+// any later version.
+//
+// MuPDF is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+// details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with MuPDF. If not, see <https://www.gnu.org/licenses/agpl-3.0.en.html>
+//
+// Alternative licensing terms are available from the licensor.
+// For commercial licensing, see <https://www.artifex.com/> or contact
+// Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco,
+// CA 94129, USA, for further information.
+
+#ifndef MUPDF_PKCS7_OPENSSL_H
+#define MUPDF_PKCS7_OPENSSL_H
+
+#include "mupdf/pdf/document.h"
+#include "mupdf/pdf/form.h"
+
+/* This an example pkcs7 implementation using openssl. These are the types of functions that you
+ * will likely need to sign documents and check signatures within documents. In particular, to
+ * sign a document, you need a function that derives a pdf_pkcs7_signer object from a certificate
+ * stored by the operating system or within a file. */
+
+/* Check a signature's digest against ranges of bytes drawn from a stream */
+pdf_signature_error pkcs7_openssl_check_digest(fz_context *ctx, fz_stream *stm, char *sig, size_t sig_len);
+
+/* Check a signature's certificate is trusted */
+pdf_signature_error pkcs7_openssl_check_certificate(char *sig, size_t sig_len);
+
+/* Obtain the distinguished name information from signature's certificate */
+pdf_pkcs7_distinguished_name *pkcs7_openssl_distinguished_name(fz_context *ctx, char *sig, size_t sig_len);
+
+/* Read the certificate and private key from a pfx file, holding it as an opaque structure */
+pdf_pkcs7_signer *pkcs7_openssl_read_pfx(fz_context *ctx, const char *pfile, const char *pw);
+
+pdf_pkcs7_verifier *pkcs7_openssl_new_verifier(fz_context *ctx);
+
+#endif