diff --git a/tests/data_files/Makefile b/tests/data_files/Makefile
index d32b43f..38ed038 100644
--- a/tests/data_files/Makefile
+++ b/tests/data_files/Makefile
@@ -1006,49 +1006,49 @@
 	$(OPENSSL) pkey -pubin -in $< -out $@ -outform DER
 all_final += server1.pubkey.der
 
-rsa4096_pub.pem.der: rsa4096_pub.pem
+rsa4096_pub.der: rsa4096_pub.pem
 	$(OPENSSL) pkey -pubin -in $< -out $@ -outform DER
-all_final += rsa4096_pub.pem.der
+all_final += rsa4096_pub.der
 
-ec_pub.pem.der: ec_pub.pem
+ec_pub.der: ec_pub.pem
 	$(OPENSSL) pkey -pubin -in $< -out $@ -outform DER
-all_final += ec_pub.pem.der
+all_final += ec_pub.der
 
-ec_521_pub.pem.der: ec_521_pub.pem
+ec_521_pub.der: ec_521_pub.pem
 	$(OPENSSL) pkey -pubin -in $< -out $@ -outform DER
-all_final += ec_521_pub.pem.der
+all_final += ec_521_pub.der
 
-ec_bp512_pub.pem.der: ec_bp512_pub.pem
+ec_bp512_pub.der: ec_bp512_pub.pem
 	$(OPENSSL) pkey -pubin -in $< -out $@ -outform DER
-all_final += ec_bp512_pub.pem.der
+all_final += ec_bp512_pub.der
 
 server1.key.der: server1.key
 	$(OPENSSL) pkey -in $< -out $@ -outform DER
 all_final += server1.key.der
 
-rsa4096_prv.pem.der: rsa4096_prv.pem
+rsa4096_prv.der: rsa4096_prv.pem
 	$(OPENSSL) pkey -in $< -out $@ -outform DER
-all_final += rsa4096_prv.pem.der
+all_final += rsa4096_prv.der
 
-ec_prv.sec1.pem.der: ec_prv.sec1.pem
+ec_prv.sec1.der: ec_prv.sec1.pem
 	$(OPENSSL) pkey -in $< -out $@ -outform DER
-all_final += ec_prv.sec1.pem.der
+all_final += ec_prv.sec1.der
 
-ec_256_long_prv.pem.der: ec_256_long_prv.pem
+ec_256_long_prv.der: ec_256_long_prv.pem
 	$(OPENSSL) pkey -in $< -out $@ -outform DER
-all_final += ec_256_long_prv.pem.der
+all_final += ec_256_long_prv.der
 
-ec_521_prv.pem.der: ec_521_prv.pem
+ec_521_prv.der: ec_521_prv.pem
 	$(OPENSSL) pkey -in $< -out $@ -outform DER
-all_final += ec_521_prv.pem.der
+all_final += ec_521_prv.der
 
-ec_521_short_prv.pem.der: ec_521_short_prv.pem
+ec_521_short_prv.der: ec_521_short_prv.pem
 	$(OPENSSL) pkey -in $< -out $@ -outform DER
-all_final += ec_521_short_prv.pem.der
+all_final += ec_521_short_prv.der
 
-ec_bp512_prv.pem.der: ec_bp512_prv.pem
+ec_bp512_prv.der: ec_bp512_prv.pem
 	$(OPENSSL) pkey -in $< -out $@ -outform DER
-all_final += ec_bp512_prv.pem.der
+all_final += ec_bp512_prv.der
 
 ################################################################
 ### Generate CSRs for X.509 write test suite