diff --git a/hpccm/building_blocks/apt_get.py b/hpccm/building_blocks/apt_get.py
index 1e2fa0a..a1664db 100644
--- a/hpccm/building_blocks/apt_get.py
+++ b/hpccm/building_blocks/apt_get.py
@@ -83,7 +83,7 @@ def __init__(self, **kwargs):
 
         super(apt_get, self).__init__()
 
-        self.__apt_key = kwargs.get('_apt_key', True)
+        self.__apt_key = kwargs.get('_apt_key', False)
         self.__aptitude = kwargs.get('aptitude', False)
         self.__commands = []
         self.__download = kwargs.get('download', False)
diff --git a/hpccm/building_blocks/intel_mpi.py b/hpccm/building_blocks/intel_mpi.py
index d95c173..983893c 100644
--- a/hpccm/building_blocks/intel_mpi.py
+++ b/hpccm/building_blocks/intel_mpi.py
@@ -126,6 +126,7 @@ def __instructions(self):
             raise RuntimeError('Intel EULA was not accepted.  To accept, see the documentation for this building block')
 
         self += packages(
+            _apt_key=True,
             apt_keys=['https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS-{}.PUB'.format(self.__year)],
             apt_repositories=['deb https://apt.repos.intel.com/mpi all main'],
             ospackages=['intel-mpi-{}'.format(self.__version)],
diff --git a/hpccm/building_blocks/intel_psxe_runtime.py b/hpccm/building_blocks/intel_psxe_runtime.py
index 96c0091..371e7ad 100644
--- a/hpccm/building_blocks/intel_psxe_runtime.py
+++ b/hpccm/building_blocks/intel_psxe_runtime.py
@@ -176,6 +176,7 @@ def __instructions(self):
 
         self += packages(
             apt=self.__apt,
+            _apt_key=True,
             apt_keys = ['https://apt.repos.intel.com/{0}/GPG-PUB-KEY-INTEL-PSXE-RUNTIME-{0}'.format(self.__year)],
             apt_repositories=apt_repositories,
             aptitude=True,
diff --git a/hpccm/building_blocks/llvm.py b/hpccm/building_blocks/llvm.py
index d276cef..9e4d922 100644
--- a/hpccm/building_blocks/llvm.py
+++ b/hpccm/building_blocks/llvm.py
@@ -381,8 +381,8 @@ def __upstream_package_repos(self):
             raise RuntimeError('Unsupported Ubuntu version')
 
         return [
-            'deb http://apt.llvm.org/{0}/ llvm-toolchain-{1} main'.format(codename, codename_ver),
-            'deb-src http://apt.llvm.org/{0}/ llvm-toolchain-{1} main'.format(codename, codename_ver)]
+            'deb [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.gpg] http://apt.llvm.org/{0}/ llvm-toolchain-{1} main'.format(codename, codename_ver),
+            'deb-src [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.gpg] http://apt.llvm.org/{0}/ llvm-toolchain-{1} main'.format(codename, codename_ver)]
 
     def runtime(self, _from='0'):
         """Generate the set of instructions to install the runtime specific
diff --git a/hpccm/building_blocks/mkl.py b/hpccm/building_blocks/mkl.py
index 0d7893d..dfbd39c 100644
--- a/hpccm/building_blocks/mkl.py
+++ b/hpccm/building_blocks/mkl.py
@@ -118,6 +118,7 @@ def __instructions(self):
             raise RuntimeError('Intel EULA was not accepted.  To accept, see the documentation for this building block')
 
         self += packages(
+            _apt_key=True,
             apt_keys=['https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS-{}.PUB'.format(self.__year)],
             apt_repositories=['deb https://apt.repos.intel.com/mkl all main'],
             ospackages=['intel-mkl-64bit-{}'.format(self.__version)],
diff --git a/hpccm/building_blocks/mlnx_ofed.py b/hpccm/building_blocks/mlnx_ofed.py
index 8f2f170..993a43f 100644
--- a/hpccm/building_blocks/mlnx_ofed.py
+++ b/hpccm/building_blocks/mlnx_ofed.py
@@ -133,6 +133,7 @@ def __instructions(self):
             self += packages(ospackages=self.__ospackages)
 
         self += packages(
+            _apt_key=True,
             apt_keys=[self.__key],
             apt_repositories=['https://linux.mellanox.com/public/repo/mlnx_ofed/{0}/{1}/mellanox_mlnx_ofed.list'.format(self.__version, self.__oslabel)],
             download=bool(self.__prefix),
diff --git a/hpccm/building_blocks/nccl.py b/hpccm/building_blocks/nccl.py
index be86250..64bb210 100644
--- a/hpccm/building_blocks/nccl.py
+++ b/hpccm/building_blocks/nccl.py
@@ -124,7 +124,7 @@ def __init__(self, **kwargs):
                      'libnccl-dev={0}+cuda{1}'.format(self.__version,
                                                       self.__cuda)],
                 apt_keys=['https://developer.download.nvidia.com/compute/cuda/repos/{0}/{1}/3bf863cc.pub'.format(self.__distro_label, get_cpu_architecture())],
-                apt_repositories=['deb https://developer.download.nvidia.com/compute/cuda/repos/{0}/{1} /'.format(self.__distro_label, get_cpu_architecture())],
+                apt_repositories=['deb [signed-by=/usr/share/keyrings/3bf863cc.gpg] https://developer.download.nvidia.com/compute/cuda/repos/{0}/{1} /'.format(self.__distro_label, get_cpu_architecture())],
                 yum=['libnccl-{0}+cuda{1}'.format(self.__version, self.__cuda),
                      'libnccl-devel-{0}+cuda{1}'.format(self.__version,
                                                         self.__cuda)],
@@ -247,7 +247,7 @@ def runtime(self, _from='0'):
                 apt=['libnccl2={0}+cuda{1}'.format(self.__version,
                                                    self.__cuda)],
                 apt_keys=['https://developer.download.nvidia.com/compute/cuda/repos/{0}/{1}/3bf863cc.pub'.format(self.__distro_label, get_cpu_architecture())],
-                apt_repositories=['deb https://developer.download.nvidia.com/compute/cuda/repos/{0}/{1} /'.format(self.__distro_label, get_cpu_architecture())],
+                apt_repositories=['deb [signed-by=/usr/share/keyrings/3bf863cc.gpg] https://developer.download.nvidia.com/compute/cuda/repos/{0}/{1} /'.format(self.__distro_label, get_cpu_architecture())],
                 yum=['libnccl-{0}+cuda{1}'.format(self.__version, self.__cuda)],
                 yum_keys=['https://developer.download.nvidia.com/compute/cuda/repos/{0}/{1}/3bf863cc.pub'.format(self.__distro_label, get_cpu_architecture())],
                 yum_repositories=['https://developer.download.nvidia.com/compute/cuda/repos/{0}/{1}'.format(self.__distro_label, get_cpu_architecture())])
diff --git a/hpccm/building_blocks/packages.py b/hpccm/building_blocks/packages.py
index ae8b7aa..b67ef87 100644
--- a/hpccm/building_blocks/packages.py
+++ b/hpccm/building_blocks/packages.py
@@ -134,7 +134,7 @@ def __init__(self, **kwargs):
         super(packages, self).__init__()
 
         self.__apt = kwargs.get('apt', [])
-        self.__apt_key = kwargs.get('_apt_key', True)
+        self.__apt_key = kwargs.get('_apt_key', False)
         self.__apt_keys = kwargs.get('apt_keys', [])
         self.__apt_ppas = kwargs.get('apt_ppas', [])
         self.__apt_repositories = kwargs.get('apt_repositories', [])
diff --git a/test/test_apt_get.py b/test/test_apt_get.py
index 639a82c..2ec68c1 100644
--- a/test/test_apt_get.py
+++ b/test/test_apt_get.py
@@ -44,27 +44,11 @@ def test_basic(self):
         gfortran && \
     rm -rf /var/lib/apt/lists/*''')
 
-    @ubuntu
-    @docker
-    def test_add_repo(self):
-        """Add repo and key"""
-        a = apt_get(keys=['https://www.example.com/key.pub'],
-                    ospackages=['example'],
-                    repositories=['deb http://www.example.com all main'])
-        self.assertEqual(str(a),
-r'''RUN wget -qO - https://www.example.com/key.pub | apt-key add - && \
-    echo "deb http://www.example.com all main" >> /etc/apt/sources.list.d/hpccm.list && \
-    apt-get update -y && \
-    DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
-        example && \
-    rm -rf /var/lib/apt/lists/*''')
-
     @ubuntu
     @docker
     def test_add_repo_signed_by(self):
         """Add repo and key, using the signed-by method rather than apt-key"""
-        a = apt_get(_apt_key=False,
-                    keys=['https://www.example.com/key.pub'],
+        a = apt_get(keys=['https://www.example.com/key.pub'],
                     ospackages=['example'],
                     repositories=['deb [signed-by=/usr/share/keyrings/key.gpg] http://www.example.com all main'])
         self.assertEqual(str(a),
diff --git a/test/test_llvm.py b/test/test_llvm.py
index 0cccd65..3e35935 100644
--- a/test/test_llvm.py
+++ b/test/test_llvm.py
@@ -330,9 +330,11 @@ def test_upstream_ubuntu16(self):
         gnupg \
         wget && \
     rm -rf /var/lib/apt/lists/*
-RUN wget -qO - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add - && \
-    echo "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-10 main" >> /etc/apt/sources.list.d/hpccm.list && \
-    echo "deb-src http://apt.llvm.org/xenial/ llvm-toolchain-xenial-10 main" >> /etc/apt/sources.list.d/hpccm.list && \
+RUN mkdir -p /usr/share/keyrings && \
+    rm -f /usr/share/keyrings/llvm-snapshot.gpg.gpg && \
+    wget -qO - https://apt.llvm.org/llvm-snapshot.gpg.key | gpg --dearmor -o /usr/share/keyrings/llvm-snapshot.gpg.gpg && \
+    echo "deb [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.gpg] http://apt.llvm.org/xenial/ llvm-toolchain-xenial-10 main" >> /etc/apt/sources.list.d/hpccm.list && \
+    echo "deb-src [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.gpg] http://apt.llvm.org/xenial/ llvm-toolchain-xenial-10 main" >> /etc/apt/sources.list.d/hpccm.list && \
     apt-get update -y && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
         clang-10 \
@@ -356,9 +358,11 @@ def test_upstream_ubuntu18(self):
         gnupg \
         wget && \
     rm -rf /var/lib/apt/lists/*
-RUN wget -qO - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add - && \
-    echo "deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic main" >> /etc/apt/sources.list.d/hpccm.list && \
-    echo "deb-src http://apt.llvm.org/bionic/ llvm-toolchain-bionic main" >> /etc/apt/sources.list.d/hpccm.list && \
+RUN mkdir -p /usr/share/keyrings && \
+    rm -f /usr/share/keyrings/llvm-snapshot.gpg.gpg && \
+    wget -qO - https://apt.llvm.org/llvm-snapshot.gpg.key | gpg --dearmor -o /usr/share/keyrings/llvm-snapshot.gpg.gpg && \
+    echo "deb [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.gpg] http://apt.llvm.org/bionic/ llvm-toolchain-bionic main" >> /etc/apt/sources.list.d/hpccm.list && \
+    echo "deb-src [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.gpg] http://apt.llvm.org/bionic/ llvm-toolchain-bionic main" >> /etc/apt/sources.list.d/hpccm.list && \
     apt-get update -y && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
         clang-18 \
@@ -386,9 +390,11 @@ def test_upstream_ubuntu24(self):
         gnupg \
         wget && \
     rm -rf /var/lib/apt/lists/*
-RUN wget -qO - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add - && \
-    echo "deb http://apt.llvm.org/noble/ llvm-toolchain-noble main" >> /etc/apt/sources.list.d/hpccm.list && \
-    echo "deb-src http://apt.llvm.org/noble/ llvm-toolchain-noble main" >> /etc/apt/sources.list.d/hpccm.list && \
+RUN mkdir -p /usr/share/keyrings && \
+    rm -f /usr/share/keyrings/llvm-snapshot.gpg.gpg && \
+    wget -qO - https://apt.llvm.org/llvm-snapshot.gpg.key | gpg --dearmor -o /usr/share/keyrings/llvm-snapshot.gpg.gpg && \
+    echo "deb [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.gpg] http://apt.llvm.org/noble/ llvm-toolchain-noble main" >> /etc/apt/sources.list.d/hpccm.list && \
+    echo "deb-src [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.gpg] http://apt.llvm.org/noble/ llvm-toolchain-noble main" >> /etc/apt/sources.list.d/hpccm.list && \
     apt-get update -y && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
         clang-18 \
@@ -415,9 +421,11 @@ def test_upstream_ubuntu20(self):
         gnupg \
         wget && \
     rm -rf /var/lib/apt/lists/*
-RUN wget -qO - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add - && \
-    echo "deb http://apt.llvm.org/focal/ llvm-toolchain-focal main" >> /etc/apt/sources.list.d/hpccm.list && \
-    echo "deb-src http://apt.llvm.org/focal/ llvm-toolchain-focal main" >> /etc/apt/sources.list.d/hpccm.list && \
+RUN mkdir -p /usr/share/keyrings && \
+    rm -f /usr/share/keyrings/llvm-snapshot.gpg.gpg && \
+    wget -qO - https://apt.llvm.org/llvm-snapshot.gpg.key | gpg --dearmor -o /usr/share/keyrings/llvm-snapshot.gpg.gpg && \
+    echo "deb [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.gpg] http://apt.llvm.org/focal/ llvm-toolchain-focal main" >> /etc/apt/sources.list.d/hpccm.list && \
+    echo "deb-src [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.gpg] http://apt.llvm.org/focal/ llvm-toolchain-focal main" >> /etc/apt/sources.list.d/hpccm.list && \
     apt-get update -y && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
         clang-18 \
@@ -445,9 +453,11 @@ def test_upstream_aarch64(self):
         gnupg \
         wget && \
     rm -rf /var/lib/apt/lists/*
-RUN wget -qO - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add - && \
-    echo "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-11 main" >> /etc/apt/sources.list.d/hpccm.list && \
-    echo "deb-src http://apt.llvm.org/xenial/ llvm-toolchain-xenial-11 main" >> /etc/apt/sources.list.d/hpccm.list && \
+RUN mkdir -p /usr/share/keyrings && \
+    rm -f /usr/share/keyrings/llvm-snapshot.gpg.gpg && \
+    wget -qO - https://apt.llvm.org/llvm-snapshot.gpg.key | gpg --dearmor -o /usr/share/keyrings/llvm-snapshot.gpg.gpg && \
+    echo "deb [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.gpg] http://apt.llvm.org/xenial/ llvm-toolchain-xenial-11 main" >> /etc/apt/sources.list.d/hpccm.list && \
+    echo "deb-src [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.gpg] http://apt.llvm.org/xenial/ llvm-toolchain-xenial-11 main" >> /etc/apt/sources.list.d/hpccm.list && \
     apt-get update -y && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
         clang-11 \
diff --git a/test/test_nccl.py b/test/test_nccl.py
index df23c72..da2ee91 100644
--- a/test/test_nccl.py
+++ b/test/test_nccl.py
@@ -46,8 +46,10 @@ def test_defaults_ubuntu(self):
         gnupg \
         wget && \
     rm -rf /var/lib/apt/lists/*
-RUN wget -qO - https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64/3bf863cc.pub | apt-key add - && \
-    echo "deb https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64 /" >> /etc/apt/sources.list.d/hpccm.list && \
+RUN mkdir -p /usr/share/keyrings && \
+    rm -f /usr/share/keyrings/3bf863cc.gpg && \
+    wget -qO - https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64/3bf863cc.pub | gpg --dearmor -o /usr/share/keyrings/3bf863cc.gpg && \
+    echo "deb [signed-by=/usr/share/keyrings/3bf863cc.gpg] https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64 /" >> /etc/apt/sources.list.d/hpccm.list && \
     apt-get update -y && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
         libnccl-dev=2.12.10-1+cuda11.6 \
@@ -69,8 +71,10 @@ def test_defaults_ubuntu18(self):
         gnupg \
         wget && \
     rm -rf /var/lib/apt/lists/*
-RUN wget -qO - https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64/3bf863cc.pub | apt-key add - && \
-    echo "deb https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64 /" >> /etc/apt/sources.list.d/hpccm.list && \
+RUN mkdir -p /usr/share/keyrings && \
+    rm -f /usr/share/keyrings/3bf863cc.gpg && \
+    wget -qO - https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64/3bf863cc.pub | gpg --dearmor -o /usr/share/keyrings/3bf863cc.gpg && \
+    echo "deb [signed-by=/usr/share/keyrings/3bf863cc.gpg] https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64 /" >> /etc/apt/sources.list.d/hpccm.list && \
     apt-get update -y && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
         libnccl-dev=2.12.10-1+cuda11.6 \
@@ -92,8 +96,10 @@ def test_ubuntu_ppc64le(self):
         gnupg \
         wget && \
     rm -rf /var/lib/apt/lists/*
-RUN wget -qO - https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/ppc64el/3bf863cc.pub | apt-key add - && \
-    echo "deb https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/ppc64el /" >> /etc/apt/sources.list.d/hpccm.list && \
+RUN mkdir -p /usr/share/keyrings && \
+    rm -f /usr/share/keyrings/3bf863cc.gpg && \
+    wget -qO - https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/ppc64el/3bf863cc.pub | gpg --dearmor -o /usr/share/keyrings/3bf863cc.gpg && \
+    echo "deb [signed-by=/usr/share/keyrings/3bf863cc.gpg] https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/ppc64el /" >> /etc/apt/sources.list.d/hpccm.list && \
     apt-get update -y && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
         libnccl-dev=2.4.8-1+cuda9.2 \
@@ -217,8 +223,10 @@ def test_runtime(self):
         gnupg \
         wget && \
     rm -rf /var/lib/apt/lists/*
-RUN wget -qO - https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64/3bf863cc.pub | apt-key add - && \
-    echo "deb https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64 /" >> /etc/apt/sources.list.d/hpccm.list && \
+RUN mkdir -p /usr/share/keyrings && \
+    rm -f /usr/share/keyrings/3bf863cc.gpg && \
+    wget -qO - https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64/3bf863cc.pub | gpg --dearmor -o /usr/share/keyrings/3bf863cc.gpg && \
+    echo "deb [signed-by=/usr/share/keyrings/3bf863cc.gpg] https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64 /" >> /etc/apt/sources.list.d/hpccm.list && \
     apt-get update -y && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
         libnccl2=2.12.10-1+cuda11.6 && \