diff --git a/aiosmtpd/tests/certs/__init__.py b/aiosmtpd/tests/certs/__init__.py
deleted file mode 100644
index e69de29bb..000000000
diff --git a/aiosmtpd/tests/certs/server.crt b/aiosmtpd/tests/certs/server.crt
deleted file mode 100644
index 04f19cf4c..000000000
--- a/aiosmtpd/tests/certs/server.crt
+++ /dev/null
@@ -1,23 +0,0 @@
------BEGIN CERTIFICATE-----
-MIID6DCCAtCgAwIBAgIJAOT/DNOqIMqmMA0GCSqGSIb3DQEBCwUAMIGHMQswCQYD
-VQQGEwJVUzELMAkGA1UECAwCQVIxEjAQBgNVBAcMCUdyZWVud29vZDERMA8GA1UE
-CgwIQWlvc210cGQxEDAOBgNVBAsMB0RldlRlYW0xDDAKBgNVBAMMA2FlczEkMCIG
-CSqGSIb3DQEJARYVd2F5bmVAd2F5bmV3ZXJuZXIuY29tMCAXDTE5MDYwMTEzNTUy
-NloYDzIxMTkwNTA4MTM1NTI2WjCBhzELMAkGA1UEBhMCVVMxCzAJBgNVBAgMAkFS
-MRIwEAYDVQQHDAlHcmVlbndvb2QxETAPBgNVBAoMCEFpb3NtdHBkMRAwDgYDVQQL
-DAdEZXZUZWFtMQwwCgYDVQQDDANhZXMxJDAiBgkqhkiG9w0BCQEWFXdheW5lQHdh
-eW5ld2VybmVyLmNvbTCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMXp
-glx/G19+jt/m/AQAy4+85ng3L1/PsXri91SpvPz1YD7Z3/0Yz3SFyuP1mkRCTplO
-H3Ok1BVbnycHxBDLBkbEjoJOfzMWxsV1Xp1vE4XEVQaq111pjgxQoFD1qU9vOs4c
-0g54PSTtGio0WCOcJq1fWXz9T1QqM5n4MAL2KzFNkqfyyhCesoja4qnPn9n8MCjk
-TFslwX/2xJVXrsZyGH0IwiGmJDzkW3/FgXj0brcRZe4BYx/BM7ka1LDNnrdUQ7Wj
-GuYbC7mQLWzOUJBF+UQUWHbPadCEPYpAgd4J4seME2XUW/ygi95oY6mJcZGOyz0c
-c8D/Dja8Elt5DeTYypsCAwEAAaNTMFEwHQYDVR0OBBYEFDofuwFE+DEx8uQisFlQ
-Dfn4LIqdMB8GA1UdIwQYMBaAFDofuwFE+DEx8uQisFlQDfn4LIqdMA8GA1UdEwEB
-/wQFMAMBAf8wDQYJKoZIhvcNAQELBQADggEBAKdtV5GiiE66bZyqh7aKAOJb6dAe
-qAD8LH9u2hqili7fHNzRQLppSiNGGxy/yZoqh7+I3Z64km5jEiSiw2bY7vqbhReC
-qU57Dlf5Q4PQVSe36d+2T/g0oGq1pzJkfY27Pse+e9c/m4FkKeEltdqS8Tl2WJFI
-Qfux88wBnfrZWCgCvZFQGD6RaqEx9Z2//cUOmU+FcM+JHfbfnQy2QEY13CKQfniP
-YBprCg866+ecVC+J+Aeu9ubZgv557SJwJ/0b4rsQ/ETUw95g6AxqdHntDTrWamxQ
-iKiGHt3N9iEdnnjXsKYNMsOFXSHHG10PtBQUpNOSUrp5HMb1Kd0oTdNz/kU=
------END CERTIFICATE-----
diff --git a/aiosmtpd/tests/certs/server.key b/aiosmtpd/tests/certs/server.key
deleted file mode 100644
index f22e0f59e..000000000
--- a/aiosmtpd/tests/certs/server.key
+++ /dev/null
@@ -1,28 +0,0 @@
------BEGIN PRIVATE KEY-----
-MIIEvgIBADANBgkqhkiG9w0BAQEFAASCBKgwggSkAgEAAoIBAQDF6YJcfxtffo7f
-5vwEAMuPvOZ4Ny9fz7F64vdUqbz89WA+2d/9GM90hcrj9ZpEQk6ZTh9zpNQVW58n
-B8QQywZGxI6CTn8zFsbFdV6dbxOFxFUGqtddaY4MUKBQ9alPbzrOHNIOeD0k7Roq
-NFgjnCatX1l8/U9UKjOZ+DAC9isxTZKn8soQnrKI2uKpz5/Z/DAo5ExbJcF/9sSV
-V67Gchh9CMIhpiQ85Ft/xYF49G63EWXuAWMfwTO5GtSwzZ63VEO1oxrmGwu5kC1s
-zlCQRflEFFh2z2nQhD2KQIHeCeLHjBNl1Fv8oIveaGOpiXGRjss9HHPA/w42vBJb
-eQ3k2MqbAgMBAAECggEBAMLwy8giJys7tK2Ujn2+7sMpNPYKnW5JXK8HasmI269q
-Xp/p6XgafRVwR7WckJRVn6ffzJkTLRfQhIZkXtqPsCH6r8hoW2BOOgH7JvP5mggz
-p/CGTNYlB5bXv+Ge6GNm00x8FOfNxaReq1wQ7RQ+VdaFydaUiBQF8YficCAqq8bF
-v2q/5XBydcJ4N2fyI4Mm3g03NIiXjeCNbxU5MBTwx2W6xN+PitN/KPGrC/KQoQEt
-PibnBkojBFfty8FTjISX/7ZKaQBp3UEktccru0k1V2LpOJ+aQMfPLGSgMdyx8hei
-oQbwv97dQfTjMaC3z53ae2sbfOyFmurWcV8Yhlo1uQECgYEA528s2Gsybcg1NQYo
-63Z7UYNd4PWOIHVuaf6XX06e0zUncaY0yf5sb0W1VTrXJ6VdgRT1Et9kkgYKZ2I7
-zsLnJQQiB0Xk7K+kha9WRgmtsxqsks9E61S/K+Ao0hNBeegwn8G6tu8KQlFDKVF0
-LN/SU/Q9J2/CVeaMDK8fugs3yoECgYEA2utto2CJ3TALc451yhqYiVHMq2WLW3M0
-+ctrRqTQJ/vgTgCXNDNZPPY+xY83Hbcaw4XxBUI9idNyorqUP3Z05kKEyZUSe4YK
-SnRi5+m/YLghNCX/MDAQasmCvV8I3ZXvzqP0TuAQW3XETqs3Cwy5wJfGXYxkVf41
-4fe0ypvo7xsCgYA+C744HzUb3Yr2NjqONeuFxPRMNUjvRsxdOlYWxRsrgJqci3Sn
-msAzbLraqLW5+UmCK74wWxe5Vkk/wkRKgFI7yEnfLUvccJJpDMLScBHTbJlLmqnd
-dZDzEFuhRmxNZIR0sBmApcFYWjTpRN8ikLbwrxAeHIY7RV3SoLiexhclAQKBgAD4
-2KTIEfSkePiLYmSCV7kMXu9H5SWDznFpgNFwe+ghiy5tfD5kF/pYUZEJAMKmBH1n
-w9k1IRbSlIi6cVwSx5QaKYLHoaxgvPz1pVbIR+xDBQq5PHfXTstal7UFjgGF3+m3
-+qa7AfeV/0gmJHltFgoP4naZ3/wtw8l8ExZvOMqPAoGBAMG9pMCCY653KfRQ237I
-m/ds9b3VmaLZ5wAwoAEeU/kfwVa27GlP6uDwz6xJmn3XLQ29YwWx8hgqIBm5TfBU
-EYQE2RNEcTOY5fnT7QK+xrKyvr3o8fTxCV15EzX/Nwc723QCO8mXN/8ekAhBRHQ7
-6QRoqSt0NeWpSSVRTNwYwFrL
------END PRIVATE KEY-----
diff --git a/aiosmtpd/tests/certs/server_alt.crt b/aiosmtpd/tests/certs/server_alt.crt
deleted file mode 100644
index ded67db07..000000000
--- a/aiosmtpd/tests/certs/server_alt.crt
+++ /dev/null
@@ -1,23 +0,0 @@
------BEGIN CERTIFICATE-----
-MIID5jCCAs6gAwIBAgIJAMEFH58o28ymMA0GCSqGSIb3DQEBCwUAMIGGMQswCQYD
-VQQGEwJVUzELMAkGA1UECAwCQVIxETAPBgNVBAcMCE1hdW1lbGxlMREwDwYDVQQK
-DAhBaW9zbXRwZDEQMA4GA1UECwwHRGV2VGVhbTEMMAoGA1UEAwwDYWVzMSQwIgYJ
-KoZIhvcNAQkBFhV3YXluZUB3YXluZXdlcm5lci5jb20wIBcNMjEwMjIzMTczMTAx
-WhgPMjEyMTAxMzAxNzMxMDFaMIGGMQswCQYDVQQGEwJVUzELMAkGA1UECAwCQVIx
-ETAPBgNVBAcMCE1hdW1lbGxlMREwDwYDVQQKDAhBaW9zbXRwZDEQMA4GA1UECwwH
-RGV2VGVhbTEMMAoGA1UEAwwDYWVzMSQwIgYJKoZIhvcNAQkBFhV3YXluZUB3YXlu
-ZXdlcm5lci5jb20wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQDDaZsR
-N0vuvXI3nJc2faKMcCMIZ92k60yzNITrzJauuVNqZI31rxU2lEjBXWF+yd1Ag3JC
-JDzUYNlyrvSo6ij93g18+YIEfmlYcyawLvKEeV1nA3vC0/9uK4ruhcdRAPhkVi6Z
-/GGvjMj05ILFtX6cW3XPHyKJYVFj82muxmXqSjs8kncqlU/ByRb295X80LMwR3bH
-Tr5BOez2jCWPOK38OqE/mhL7kt/Xd/c8csCO+H3Ep1lGFb9gCHi0/B06I6lJ490x
-PRYfYhcObpfxgtJ6EB17ZAnKySc46pRhzgWPry2G2J/B8q0J+ySOjQ/+ciIQP1Hf
-17K5/teUZs3AuvlTAgMBAAGjUzBRMB0GA1UdDgQWBBS1ZwfD6bcyw1WMEP+2ol3R
-aiIwFDAfBgNVHSMEGDAWgBS1ZwfD6bcyw1WMEP+2ol3RaiIwFDAPBgNVHRMBAf8E
-BTADAQH/MA0GCSqGSIb3DQEBCwUAA4IBAQBXogsxOG74QJWfqEvTfJtL2Zf1+Krg
-Da0JhUcFhewjvkfjBS/pMWRQGx35IRZKztbq3PBhgIS7oCnpqlHWwXqID3Ygypee
-C3ZNoedWvgI9HAPZCL/Se2Dv+fh2WrARECMPxEgIJ53vCjmAAO/nt7gKHZHW5KgW
-DcsdcLE5nfVwUEyS+gJvMEx56hUdYldBN2plXqumMsaMXyTPYCzqaNxHTBcTJogd
-tNzUk0M0+I1PRS3/47pZOex8fbbok0nkdGoHT02URv/+7MV7dwzOmuG0qdtDP0Yo
-rZjNk76yt3/azUuaSc9LqXN+BOeHCBz69xqwZEeV/jGQ+bl2XS/OgMKw
------END CERTIFICATE-----
diff --git a/aiosmtpd/tests/certs/server_alt.key b/aiosmtpd/tests/certs/server_alt.key
deleted file mode 100644
index 1b0f762b4..000000000
--- a/aiosmtpd/tests/certs/server_alt.key
+++ /dev/null
@@ -1,28 +0,0 @@
------BEGIN PRIVATE KEY-----
-MIIEvwIBADANBgkqhkiG9w0BAQEFAASCBKkwggSlAgEAAoIBAQDDaZsRN0vuvXI3
-nJc2faKMcCMIZ92k60yzNITrzJauuVNqZI31rxU2lEjBXWF+yd1Ag3JCJDzUYNly
-rvSo6ij93g18+YIEfmlYcyawLvKEeV1nA3vC0/9uK4ruhcdRAPhkVi6Z/GGvjMj0
-5ILFtX6cW3XPHyKJYVFj82muxmXqSjs8kncqlU/ByRb295X80LMwR3bHTr5BOez2
-jCWPOK38OqE/mhL7kt/Xd/c8csCO+H3Ep1lGFb9gCHi0/B06I6lJ490xPRYfYhcO
-bpfxgtJ6EB17ZAnKySc46pRhzgWPry2G2J/B8q0J+ySOjQ/+ciIQP1Hf17K5/teU
-Zs3AuvlTAgMBAAECggEBAKukbjWACa1pMBMS82tEjWun782pVfFPUO6zufFYoh5U
-4KU6L8tWf16SfxmBiWqRq0rIaqsYI2o0q6tla7eW/myHB/f3PTHvS18KvjfQ9OpR
-pC4gzCuEhP9jNcRvM3S+Um/nl0Vgfvlwwu8AbLF2ywBSAbftVCuxlIkjvHdtAwX3
-pmfPCn40jcFHIM8eRu2+gsUccY9Lmed2Ct/C1SdA4kzDLrYfVw4U/aGOtf4p7YEa
-k89/SRPR29AMlDwOn38qHm9o08P08E+6XO9bmrrdnKlbUtx8BhEL1FtsN5ErZk+B
-dI/kYpVec3cTEC1D/qz+vNFmeb3aBtoJmwHXC5LaxwkCgYEA7Jlf6xWMKY+8VmvH
-C2NF+EQ7YrrrMkpJY+XXdzDjGYDN6pKF6MBuyCpKt+5DWc9ftqriPKbj+mvTdsLW
-lGnqGRfJyzqy5eM7jSQFRpbWjd3g/hsShduYdNj2G1lJbKUOz+6lHg7xWo0sVHaS
-+RpI2Uou5pVwG6Ifc7ID1u0qLf8CgYEA02+nLT3A7FtOd5wCIp3Sk3Nr/KhWE1Aw
-iq0OMHFVFFf3JY4xb2+GEsOupwEpMvYVNrb+dIhXP0FdAigRo876F0aDWMDxsKuH
-4R76jWSdfycIb5TV1VSE2Ald0RybGioTLWLLr5YDmZKlPEF1ibwCtebPxlXrWgHI
-F2Qz+CXOHK0CgYEAgVOo8Yg6sDEoQpjxGRFvmrA5QdNoYnnmudtVtoobaMJWTEVB
-OyOMqo8rfnSXjgzjhabMuViEP0sXMNB5mHB4jLTLEfKI/U4DLDgnRhmHN86zgFJu
-AosxP5WkmPhqQR/MA+6vhMmoNdX7CEQ0PEOY1GVPU60VtZUd2hDRNnc22iMCgYAK
-xbaDxJCuuhwuVeF5+AaBgrDux3jTNRO0DQsbBrsp9S1fWXZFUi5HiHa+hX2e3hDI
-n9wo/cVMML1XXclASkxNoUcR34qw0Jx0qMplJ8oqb0erv66BVvQJubhw7f8s/xXJ
-Cy6LfJ4kVedbQY6GfPC6ac8OMNRz2oFiR7WqH+r3ZQKBgQDnCC7nEP/KLQqsP7E3
-EmtMtiXdpKBQvukezF2Zv8xNMeouLfMJdf1XMMTL06Qpj1OCAb76SIqFJOtp8+aR
-P3w2jZQK1A62eBvpjjlZCauaA4MZaVlvaKsExkM0XDho4Xt6Q0xkqjUme4hLcdr/
-xXvhZaWMLnl57GOQL6GBba3LXQ==
------END PRIVATE KEY-----
diff --git a/aiosmtpd/tests/conftest.py b/aiosmtpd/tests/conftest.py
index 0c6910317..49d847d21 100644
--- a/aiosmtpd/tests/conftest.py
+++ b/aiosmtpd/tests/conftest.py
@@ -9,10 +9,10 @@
 from contextlib import suppress
 from functools import wraps
 from smtplib import SMTP as SMTPClient
-from typing import Any, Callable, Generator, NamedTuple, Optional, Type, TypeVar
+from typing import Any, Callable, Generator, Iterator, NamedTuple, Optional, Type, TypeVar
 
 import pytest
-from pkg_resources import resource_filename
+import trustme
 from pytest_mock import MockFixture
 
 from aiosmtpd.controller import Controller
@@ -32,8 +32,6 @@
     "handler_data",
     "Global",
     "AUTOSTOP_DELAY",
-    "SERVER_CRT",
-    "SERVER_KEY",
 ]
 
 
@@ -73,8 +71,6 @@ def set_addr_from(cls, contr: Controller):
 # If less than 1.0, might cause intermittent error if test system
 # is too busy/overloaded.
 AUTOSTOP_DELAY = 1.5
-SERVER_CRT = resource_filename("aiosmtpd.tests.certs", "server.crt")
-SERVER_KEY = resource_filename("aiosmtpd.tests.certs", "server.key")
 
 # endregion
 
@@ -315,27 +311,50 @@ def client(request: pytest.FixtureRequest) -> Generator[SMTPClient, None, None]:
 
 
 @pytest.fixture
-def ssl_context_server() -> ssl.SSLContext:
+def tls_certificate_authority() -> trustme.CA:
+    return trustme.CA()
+
+
+@pytest.fixture
+def tls_certificate(tls_certificate_authority: trustme.CA) -> trustme.LeafCert:
+    return tls_certificate_authority.issue_cert(
+        "localhost",
+        "xn--prklad-4va.localhost",  # príklad.localhost
+        "127.0.0.1",
+        "::1",
+    )
+
+
+@pytest.fixture
+def ssl_context_server(tls_certificate: trustme.LeafCert) -> ssl.SSLContext:
     """
     Provides a server-side SSL Context
     """
-    context = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
-    context.check_hostname = False
-    context.load_cert_chain(SERVER_CRT, SERVER_KEY)
-    #
-    return context
+    ssl_ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
+    tls_certificate.configure_cert(ssl_ctx)
+    return ssl_ctx
 
 
 @pytest.fixture
-def ssl_context_client() -> ssl.SSLContext:
+def ssl_context_client(tls_certificate_authority: trustme.CA) -> ssl.SSLContext:
     """
     Provides a client-side SSL Context
     """
-    context = ssl.create_default_context(ssl.Purpose.SERVER_AUTH)
-    context.check_hostname = False
-    context.load_verify_locations(SERVER_CRT)
-    #
-    return context
+    ssl_ctx = ssl.create_default_context(purpose=ssl.Purpose.SERVER_AUTH)
+    tls_certificate_authority.configure_trust(ssl_ctx)
+    return ssl_ctx
+
+
+@pytest.fixture
+def tls_cert_pem_path(tls_certificate: trustme.LeafCert) -> Iterator[str]:
+    with tls_certificate.cert_chain_pems[0].tempfile() as cert_pem:
+        yield cert_pem
+
+
+@pytest.fixture
+def tls_key_pem_path(tls_certificate: trustme.LeafCert) -> Iterator[str]:
+    with tls_certificate.private_key_pem.tempfile() as key_pem:
+        yield key_pem
 
 
 # Please keep the scope as "module"; setting it as "function" (the default) somehow
diff --git a/aiosmtpd/tests/test_main.py b/aiosmtpd/tests/test_main.py
index b53cd8566..b64031f2f 100644
--- a/aiosmtpd/tests/test_main.py
+++ b/aiosmtpd/tests/test_main.py
@@ -21,7 +21,7 @@
 from aiosmtpd.main import main, parseargs
 from aiosmtpd.testing.helpers import catchup_delay
 from aiosmtpd.testing.statuscodes import SMTP_STATUS_CODES as S
-from aiosmtpd.tests.conftest import AUTOSTOP_DELAY, SERVER_CRT, SERVER_KEY
+from aiosmtpd.tests.conftest import AUTOSTOP_DELAY
 
 try:
     import pwd
@@ -199,24 +199,24 @@ def test_debug_3(self):
 
 @pytest.mark.skipif(sys.platform == "darwin", reason="No idea why these are failing")
 class TestMainByWatcher:
-    def test_tls(self, temp_event_loop):
+    def test_tls(self, temp_event_loop, tls_cert_pem_path, tls_key_pem_path):
         with watcher_process(watch_for_tls) as retq:
             temp_event_loop.call_later(AUTOSTOP_DELAY, temp_event_loop.stop)
-            main_n("--tlscert", str(SERVER_CRT), "--tlskey", str(SERVER_KEY))
+            main_n("--tlscert", tls_cert_pem_path, "--tlskey", tls_key_pem_path)
             catchup_delay()
         has_starttls = retq.get()
         assert has_starttls is True
         require_tls = retq.get()
         assert require_tls is True
 
-    def test_tls_noreq(self, temp_event_loop):
+    def test_tls_noreq(self, temp_event_loop, tls_cert_pem_path, tls_key_pem_path):
         with watcher_process(watch_for_tls) as retq:
             temp_event_loop.call_later(AUTOSTOP_DELAY, temp_event_loop.stop)
             main_n(
                 "--tlscert",
-                str(SERVER_CRT),
+                tls_cert_pem_path,
                 "--tlskey",
-                str(SERVER_KEY),
+                tls_key_pem_path,
                 "--no-requiretls",
             )
             catchup_delay()
@@ -225,10 +225,10 @@ def test_tls_noreq(self, temp_event_loop):
         require_tls = retq.get()
         assert require_tls is False
 
-    def test_smtps(self, temp_event_loop):
+    def test_smtps(self, temp_event_loop, tls_cert_pem_path, tls_key_pem_path):
         with watcher_process(watch_for_smtps) as retq:
             temp_event_loop.call_later(AUTOSTOP_DELAY, temp_event_loop.stop)
-            main_n("--smtpscert", str(SERVER_CRT), "--smtpskey", str(SERVER_KEY))
+            main_n("--smtpscert", tls_cert_pem_path, "--smtpskey", tls_key_pem_path)
             catchup_delay()
         has_smtps = retq.get()
         assert has_smtps is True
@@ -335,16 +335,18 @@ def test_norequiretls(self, capsys, mocker):
         assert args.requiretls is False
 
     @pytest.mark.parametrize(
-        ("certfile", "keyfile", "expect"),
+        ("certfile_present", "keyfile_present", "expect"),
         [
-            ("x", "x", "Cert file x not found"),
-            (SERVER_CRT, "x", "Key file x not found"),
-            ("x", SERVER_KEY, "Cert file x not found"),
+            (False, False, "Cert file x not found"),
+            (True, False, "Key file x not found"),
+            (False, True, "Cert file x not found"),
         ],
         ids=["x-x", "cert-x", "x-key"],
     )
     @pytest.mark.parametrize("meth", ["smtps", "tls"])
-    def test_ssl_files_err(self, capsys, mocker, meth, certfile, keyfile, expect):
+    def test_ssl_files_err(self, capsys, mocker, meth, certfile_present, keyfile_present, expect, request):
+        certfile = request.getfixturevalue("tls_cert_pem_path") if certfile_present else "x"
+        keyfile = request.getfixturevalue("tls_key_pem_path") if keyfile_present else "x"
         mocker.patch("aiosmtpd.main.PROGRAM", "smtpd")
         with pytest.raises(SystemExit) as exc:
             parseargs((f"--{meth}cert", certfile, f"--{meth}key", keyfile))
diff --git a/requirements.txt b/requirements.txt
index bbc5921fa..7ebd9342d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,10 @@
+# Python 3.8 is EOL, so latest versions of some packages do not support it, use newest compatible versions 
 atpublic==5.0
 attrs==24.2.0
 coverage==7.6.1
+cryptography==41.0.7; python_version == '3.8' and platform_python_implementation == "PyPy"
 pytest==8.3.4
 pytest-cov==5.0.0
 pytest-mock==3.14.0
+trustme==1.1.0; python_version == '3.8'
+trustme==1.2.1; python_version > '3.8'
diff --git a/tox.ini b/tox.ini
index 8282343de..91144d9af 100644
--- a/tox.ini
+++ b/tox.ini
@@ -28,6 +28,7 @@ deps =
     pytest-profiling
     pytest-sugar
     py # needed for pytest-sugar as it doesn't declare dependency on it.
+    trustme
     !nocov: coverage>=7.0.1
     !nocov: coverage[toml]
     !nocov: coverage-conditional-plugin