diff --git a/src/hsm/cmd_decrypt_asym.c b/src/hsm/cmd_decrypt_asym.c
index 893dcc3..bee94dd 100644
--- a/src/hsm/cmd_decrypt_asym.c
+++ b/src/hsm/cmd_decrypt_asym.c
@@ -129,15 +129,18 @@ int cmd_decrypt_asym() {
             return SW_DATA_INVALID();
         }
         size_t olen = 0;
+        // The SmartCard-HSM returns the point result of the DH operation
+		// with a leading '04'
+        res_APDU[0] = 0x04;
         r =
-            mbedtls_ecdh_calc_secret(&ctx, &olen, res_APDU, MBEDTLS_ECP_MAX_BYTES, random_gen,
+            mbedtls_ecdh_calc_secret(&ctx, &olen, res_APDU + 1, MBEDTLS_ECP_MAX_BYTES, random_gen,
                                      NULL);
         mbedtls_ecdh_free(&ctx);
         if (r != 0) {
             return SW_EXEC_ERROR();
         }
         if (p2 == ALGO_EC_DH) {
-            res_APDU_size = olen;
+            res_APDU_size = olen + 1;
         }
         else {
             res_APDU_size = 0;
@@ -175,7 +178,7 @@ int cmd_decrypt_asym() {
                     if (file_get_size(tf) == kdom_uid_len &&
                         memcmp(file_get_data(tf), kdom_uid, kdom_uid_len) == 0) {
                         file_new(EF_DKEK + n);
-                        if (store_dkek_key(n, res_APDU) != CCID_OK) {
+                        if (store_dkek_key(n, res_APDU + 1) != CCID_OK) {
                             return SW_EXEC_ERROR();
                         }
                         mbedtls_platform_zeroize(res_APDU, 32);
diff --git a/tests/conftest.py b/tests/conftest.py
index 4564729..5c9b718 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -411,7 +411,7 @@ class Device:
 
     def exchange(self, keyid, pubkey):
         resp = self.send(cla=0x80, command=0x62, p1=keyid, p2=Algorithm.ALGO_EC_ECDH.value, data=pubkey.public_bytes(Encoding.X962, PublicFormat.UncompressedPoint))
-        return resp
+        return resp[1:]
 
     def parse_cvc(self, data):
         car = CVC().decode(data).car()