diff --git a/tests/data_files/ec_256_long_prv.pem.der b/tests/data_files/ec_256_long_prv.pem.der
new file mode 100644
index 0000000..96e329e
--- /dev/null
+++ b/tests/data_files/ec_256_long_prv.pem.der
Binary files differ
diff --git a/tests/data_files/ec_521_prv.pem.der b/tests/data_files/ec_521_prv.pem.der
new file mode 100644
index 0000000..734714a
--- /dev/null
+++ b/tests/data_files/ec_521_prv.pem.der
Binary files differ
diff --git a/tests/data_files/ec_521_pub.pem.der b/tests/data_files/ec_521_pub.pem.der
new file mode 100644
index 0000000..5b685de
--- /dev/null
+++ b/tests/data_files/ec_521_pub.pem.der
Binary files differ
diff --git a/tests/data_files/ec_521_short_prv.pem.der b/tests/data_files/ec_521_short_prv.pem.der
new file mode 100644
index 0000000..0a1f18c
--- /dev/null
+++ b/tests/data_files/ec_521_short_prv.pem.der
Binary files differ
diff --git a/tests/data_files/ec_bp512_prv.pem.der b/tests/data_files/ec_bp512_prv.pem.der
new file mode 100644
index 0000000..2d9a3de
--- /dev/null
+++ b/tests/data_files/ec_bp512_prv.pem.der
Binary files differ
diff --git a/tests/data_files/ec_bp512_pub.pem.der b/tests/data_files/ec_bp512_pub.pem.der
new file mode 100644
index 0000000..6a8c4c7
--- /dev/null
+++ b/tests/data_files/ec_bp512_pub.pem.der
Binary files differ
diff --git a/tests/data_files/ec_prv.sec1.pem.der b/tests/data_files/ec_prv.sec1.pem.der
new file mode 100644
index 0000000..fe336b7
--- /dev/null
+++ b/tests/data_files/ec_prv.sec1.pem.der
Binary files differ
diff --git a/tests/data_files/ec_pub.pem.der b/tests/data_files/ec_pub.pem.der
new file mode 100644
index 0000000..74c5951
--- /dev/null
+++ b/tests/data_files/ec_pub.pem.der
Binary files differ
diff --git a/tests/data_files/rsa4096_prv.pem.der b/tests/data_files/rsa4096_prv.pem.der
new file mode 100644
index 0000000..86ea818
--- /dev/null
+++ b/tests/data_files/rsa4096_prv.pem.der
Binary files differ
diff --git a/tests/data_files/rsa4096_pub.pem.der b/tests/data_files/rsa4096_pub.pem.der
new file mode 100644
index 0000000..270bf3a
--- /dev/null
+++ b/tests/data_files/rsa4096_pub.pem.der
Binary files differ
diff --git a/tests/data_files/server1.key.der b/tests/data_files/server1.key.der
new file mode 100644
index 0000000..88288d1
--- /dev/null
+++ b/tests/data_files/server1.key.der
Binary files differ
diff --git a/tests/data_files/server1.pubkey.der b/tests/data_files/server1.pubkey.der
new file mode 100644
index 0000000..1a432a4
--- /dev/null
+++ b/tests/data_files/server1.pubkey.der
Binary files differ
diff --git a/tests/suites/test_suite_pkwrite.data b/tests/suites/test_suite_pkwrite.data
index cf70684..f0a8d7f 100644
--- a/tests/suites/test_suite_pkwrite.data
+++ b/tests/suites/test_suite_pkwrite.data
@@ -1,47 +1,95 @@
 Public key write check RSA
 depends_on:MBEDTLS_RSA_C:MBEDTLS_BASE64_C
-pk_write_pubkey_check:"data_files/server1.pubkey"
+pk_write_pubkey_check:"data_files/server1.pubkey":0
+
+Public key write check RSA (DER)
+depends_on:MBEDTLS_RSA_C:MBEDTLS_BASE64_C
+pk_write_pubkey_check:"data_files/server1.pubkey.der":1
 
 Public key write check RSA 4096
 depends_on:MBEDTLS_RSA_C:MBEDTLS_BASE64_C
-pk_write_pubkey_check:"data_files/rsa4096_pub.pem"
+pk_write_pubkey_check:"data_files/rsa4096_pub.pem":0
+
+Public key write check RSA 4096 (DER)
+depends_on:MBEDTLS_RSA_C:MBEDTLS_BASE64_C
+pk_write_pubkey_check:"data_files/rsa4096_pub.pem.der":1
 
 Public key write check EC 192 bits
 depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP192R1_ENABLED
-pk_write_pubkey_check:"data_files/ec_pub.pem"
+pk_write_pubkey_check:"data_files/ec_pub.pem":0
+
+Public key write check EC 192 bits (DER)
+depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP192R1_ENABLED
+pk_write_pubkey_check:"data_files/ec_pub.pem.der":1
 
 Public key write check EC 521 bits
 depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP521R1_ENABLED
-pk_write_pubkey_check:"data_files/ec_521_pub.pem"
+pk_write_pubkey_check:"data_files/ec_521_pub.pem":0
+
+Public key write check EC 521 bits (DER)
+depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP521R1_ENABLED
+pk_write_pubkey_check:"data_files/ec_521_pub.pem.der":1
 
 Public key write check EC Brainpool 512 bits
 depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_BP512R1_ENABLED
-pk_write_pubkey_check:"data_files/ec_bp512_pub.pem"
+pk_write_pubkey_check:"data_files/ec_bp512_pub.pem":0
+
+Public key write check EC Brainpool 512 bits (DER)
+depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_BP512R1_ENABLED
+pk_write_pubkey_check:"data_files/ec_bp512_pub.pem.der":1
 
 Private key write check RSA
 depends_on:MBEDTLS_RSA_C:MBEDTLS_BASE64_C
-pk_write_key_check:"data_files/server1.key"
+pk_write_key_check:"data_files/server1.key":0
+
+Private key write check RSA (DER)
+depends_on:MBEDTLS_RSA_C:MBEDTLS_BASE64_C
+pk_write_key_check:"data_files/server1.key.der":1
 
 Private key write check RSA 4096
 depends_on:MBEDTLS_RSA_C:MBEDTLS_BASE64_C
-pk_write_key_check:"data_files/rsa4096_prv.pem"
+pk_write_key_check:"data_files/rsa4096_prv.pem":0
+
+Private key write check RSA 4096 (DER)
+depends_on:MBEDTLS_RSA_C:MBEDTLS_BASE64_C
+pk_write_key_check:"data_files/rsa4096_prv.pem.der":1
 
 Private key write check EC 192 bits
 depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP192R1_ENABLED
-pk_write_key_check:"data_files/ec_prv.sec1.pem"
+pk_write_key_check:"data_files/ec_prv.sec1.pem":0
+
+Private key write check EC 192 bits (DER)
+depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP192R1_ENABLED
+pk_write_key_check:"data_files/ec_prv.sec1.pem.der":1
 
 Private key write check EC 256 bits (top bit set)
 depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED
-pk_write_key_check:"data_files/ec_256_long_prv.pem"
+pk_write_key_check:"data_files/ec_256_long_prv.pem":0
+
+Private key write check EC 256 bits (top bit set) (DER)
+depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+pk_write_key_check:"data_files/ec_256_long_prv.pem.der":1
 
 Private key write check EC 521 bits
 depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP521R1_ENABLED
-pk_write_key_check:"data_files/ec_521_prv.pem"
+pk_write_key_check:"data_files/ec_521_prv.pem":0
+
+Private key write check EC 521 bits (DER)
+depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP521R1_ENABLED
+pk_write_key_check:"data_files/ec_521_prv.pem.der":1
 
 Private key write check EC 521 bits (top byte is 0)
 depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP521R1_ENABLED
-pk_write_key_check:"data_files/ec_521_short_prv.pem"
+pk_write_key_check:"data_files/ec_521_short_prv.pem":0
+
+Private key write check EC 521 bits (top byte is 0) (DER)
+depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_SECP521R1_ENABLED
+pk_write_key_check:"data_files/ec_521_short_prv.pem.der":1
 
 Private key write check EC Brainpool 512 bits
 depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_BP512R1_ENABLED
-pk_write_key_check:"data_files/ec_bp512_prv.pem"
+pk_write_key_check:"data_files/ec_bp512_prv.pem":0
+
+Private key write check EC Brainpool 512 bits (DER)
+depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_BP512R1_ENABLED
+pk_write_key_check:"data_files/ec_bp512_prv.pem.der":1