Avoid explicitly initializing OpenSSL in verifySignature()

This is no longer required in recent OpenSSL versions and thus better left
out considering the related functions are deprecated and corresponding
cleanup was missing.

Author: Martchus

CMakeLists.txt

@@ -260,7 +260,14 @@ if (USE_PLATFORM_SPECIFIC_API_FOR_OPTIMIZING_COPY_HELPER)
 endif ()
 
 # configure tests for verification helpers which require OpenSSL
-use_crypto(LIBRARIES_VARIABLE "TEST_LIBRARIES" PACKAGES_VARIABLE "TEST_PACKAGES" OPTIONAL)
+use_crypto(
+    LIBRARIES_VARIABLE
+    "TEST_LIBRARIES"
+    PACKAGES_VARIABLE
+    "TEST_PACKAGES"
+    PACKAGE_ARGS
+    1.1.0
+    OPTIONAL)
 if ("OpenSSL::Crypto" IN_LIST "TEST_LIBRARIES")
     message(STATUS "Testing verification using OpenSSL crypto library")
     set_property(

misc/verification.h

@@ -17,14 +17,6 @@
 namespace CppUtilities {
 
 namespace Detail {
-/// \brief Initializes OpenSSL.
-/// \remarks This function is an implementation detail and must not be called by users this library.
-inline void initOpenSsl()
-{
-    ERR_load_crypto_strings();
-    OpenSSL_add_all_algorithms();
-}
-
 /// \brief Returns the current OpenSSL error.
 /// \remarks This function is an implementation detail and must not be called by users this library.
 inline std::string getOpenSslError()
@@ -83,7 +75,10 @@ inline std::string parsePemSignature(std::string_view pemSignature, std::pair<st
  * \remarks
  * - The digest algorithm is assumed to be SHA256.
  * - The key and signature must both be provided in PEM format.
- * - This function requires linking with the OpenSSL crypto library and will initialize OpenSSL.
+ * - This function requires linking with the OpenSSL crypto library. It will *not* initialize the OpenSSL crypto library
+ *   explicitly assuming OpenSSL version 1.1.0 or higher is used (which no longer requires explicit initialization). If
+ *   you are using an older version of OpenSSL you may need to call ERR_load_crypto_strings() and OpenSSL_add_all_algorithms()
+ *   before invoking this function.
  * - This function is experimental and might be changed in incompatible ways (API and ABI wise) or be completely removed
  *   in further minor/patch releases.
  *
@@ -109,7 +104,6 @@ inline std::string parsePemSignature(std::string_view pemSignature, std::pair<st
 inline std::string verifySignature(std::string_view publicKeyPem, std::string_view signaturePem, std::string_view data)
 {
     auto error = std::string();
-    Detail::initOpenSsl();
 
     auto derSignature = std::pair<std::unique_ptr<std::uint8_t[]>, std::uint32_t>();
     if (error = Detail::parsePemSignature(signaturePem, derSignature); !error.empty()) {