diff --git a/repos/libports/lib/mk/libcrypto.inc b/repos/libports/lib/mk/libcrypto.inc
index 843a1e7893..98f0a5b700 100644
--- a/repos/libports/lib/mk/libcrypto.inc
+++ b/repos/libports/lib/mk/libcrypto.inc
@@ -651,13 +651,23 @@ CC_OPT_ec/curve448/scalar          += $(CURVE448_INCLUDES)
 #
 $(SRC_C:.c=.o): buildinf.h
 
+# Taken from https://reproducible-builds.org/docs/source-date-epoch
+DATE_FMT = +%Y-%m-%d
+ifdef SOURCE_DATE_EPOCH
+	BUILD_DATE ?= $(shell date -u -d "@$(SOURCE_DATE_EPOCH)" "$(DATE_FMT)" 2>/dev/null || \
+	                      date -u -r "$(SOURCE_DATE_EPOCH)"  "$(DATE_FMT)" 2>/dev/null || \
+	                      date -u "$(DATE_FMT)")
+else
+	BUILD_DATE ?= $(shell date "$(DATE_FMT)")
+endif
+
 # Rules taken from FreeBSDs libcrypto/Makefile
 buildinf.h:
 	$(VERBOSE)( \
 		echo "#ifndef MK1MF_BUILD"                                          ;\
-		echo "/* auto-generated by libcrypto.mk for crypto/cversion.c */" ;\
+		echo "/* auto-generated by libcrypto.mk for crypto/cversion.c */"   ;\
 		echo "#define PLATFORM \"Genode-$(TARGET_CPUARCH)\""                ;\
-		echo "#define DATE \"built on: $(shell date --rfc-email)\""         ;\
+		echo "#define DATE \"built on: $(BUILD_DATE)\""                     ;\
 		echo "static const char compiler_flags[] = \"<undefined>\";"        ;\
 		echo "#endif"                                                       ;\
 	) > $@