diff --git a/core/openssl/build b/core/openssl/build
index a696f653..92eaddf4 100755
--- a/core/openssl/build
+++ b/core/openssl/build
@@ -4,10 +4,24 @@
     --prefix=/usr \
     --openssldir=/etc/ssl \
     --libdir=lib \
-    shared linux-x86_64
+    no-unit-test \
+    shared \
+    linux-x86_64
 
 make depend
 make
 make DESTDIR="$1" install_sw install_ssldirs
 
 cp -f update-certdata.sh "$1/etc/ssl"
+
+# Libretls is LibreSSL's libtls library for OpenSSL.
+(
+    cd libretls
+
+    ./configure \
+        --prefix=/usr \
+        --with-openssl="$1/usr"
+
+    make
+    make DESTDIR="$1" install
+)
diff --git a/core/openssl/checksums b/core/openssl/checksums
index a3f6dfcd..195f3029 100644
--- a/core/openssl/checksums
+++ b/core/openssl/checksums
@@ -1,2 +1,3 @@
 892a0875b9872acd04a9fde79b1f943075d5ea162415de3047c327df33fbaee5
+8a5b38a76b778da8d6f4236f1ea89e680daea971be6ee3a57e4e7ae99a883aa2
 d4bfcd9ee16eff65bdf6de1e0a3ccac667fdf52d98d0eda5c3e3f638aad13b89
diff --git a/core/openssl/sources b/core/openssl/sources
index c265c391..ecfe35e6 100644
--- a/core/openssl/sources
+++ b/core/openssl/sources
@@ -1,2 +1,3 @@
 https://www.openssl.org/source/openssl-1.1.1k.tar.gz
+https://causal.agency/libretls/libretls-3.3.3p1.tar.gz libretls
 files/update-certdata.sh