[Security] Use a CSPRNG for salts, tokens, and RNG seeding (#7192)

* [Security] Use a CSPRNG for salts, tokens, and RNG seeding

Password salts and activation tokens were generated with the global SFMT
RNG, which was seeded from a 32-bit timestamp, making registration
salts and activation tokens predictable. The game RNG used the same
timestamp seed across restarts.

Add CryptoUtil backed by OpenSSL RAND_bytes and use it for salt/token
generation and to seed RNG_SFMT with a 64-bit CSPRNG value in both the
client and server. Link libcockatrice_utility against OpenSSL::Crypto.

Took 30 seconds

Took 25 minutes

* Lint.

Took 4 minutes

Took 36 seconds

---------

Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

tests/password_hash_test.cpp

@@ -1,25 +1,9 @@
 #include "gtest/gtest.h"
-#include <libcockatrice/rng/rng_abstract.h>
-#include <libcockatrice/rng/rng_sfmt.h>
+#include <cstring>
 #include <libcockatrice/utility/passwordhasher.h>
 
-RNG_Abstract *rng;
-
 namespace
 {
-class PasswordHashTest : public ::testing::Test
-{
-protected:
-    void SetUp() override
-    {
-        rng = new RNG_SFMT;
-    }
-
-    void TearDown() override
-    {
-        delete rng;
-    }
-};
 
 TEST(PasswordHashTest, RegressionTest)
 {
@@ -29,6 +13,29 @@ TEST(PasswordHashTest, RegressionTest)
     QString hash = PasswordHasher::computeHash(password, salt);
     ASSERT_EQ(hash, salt + expected) << "The computed hash value remains the same";
 }
+
+TEST(PasswordHashTest, SaltUsesAlphanumericCharset)
+{
+    static const char alphanum[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+    const QString salt = PasswordHasher::generateRandomSalt();
+    ASSERT_EQ(salt.size(), 16);
+    for (const QChar &c : salt) {
+        ASSERT_NE(strchr(alphanum, c.toLatin1()), nullptr);
+    }
+}
+
+TEST(PasswordHashTest, SaltsAreUnique)
+{
+    const QString salt1 = PasswordHasher::generateRandomSalt();
+    const QString salt2 = PasswordHasher::generateRandomSalt();
+    ASSERT_NE(salt1, salt2);
+}
+
+TEST(PasswordHashTest, TokenHasExpectedLength)
+{
+    const QString token = PasswordHasher::generateActivationToken();
+    ASSERT_EQ(token.size(), 16);
+}
 } // namespace
 
 int main(int argc, char **argv)