diff --git a/library/pk_wrap.c b/library/pk_wrap.c
index fa296e8..0f0ae5b 100644
--- a/library/pk_wrap.c
+++ b/library/pk_wrap.c
@@ -691,11 +691,13 @@
     psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
     mbedtls_svc_key_id_t key_id = MBEDTLS_SVC_KEY_ID_INIT;
     psa_status_t status;
-    mbedtls_pk_context key;
-    int key_len;
-    unsigned char buf[MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES];
+    size_t key_len;
+    /* This buffer contains first the public key (consisting of two public
+     * points plus a header byte), then the signature (consisting of two
+     * public points). Size it for the public key which is one byte larger. */
+    unsigned char buf[PSA_KEY_EXPORT_ECC_PUBLIC_KEY_MAX_SIZE(
+            PSA_VENDOR_ECC_MAX_CURVE_BITS )];
     unsigned char *p;
-    mbedtls_pk_info_t pk_info = mbedtls_eckey_info;
     psa_algorithm_t psa_sig_md = PSA_ALG_ECDSA_ANY;
     size_t curve_bits;
     psa_ecc_family_t curve =
@@ -707,25 +709,22 @@
         return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
     }
 
-    /* mbedtls_pk_write_pubkey() expects a full PK context;
-     * re-construct one to make it happy */
-    key.pk_info = &pk_info;
-    key.pk_ctx = ctx;
-    p = buf + sizeof(buf);
-    key_len = mbedtls_pk_write_pubkey(&p, buf, &key);
-    if (key_len <= 0) {
-        return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
+    psa_set_key_type( &attributes, PSA_KEY_TYPE_ECC_PUBLIC_KEY( curve ) );
+    psa_set_key_usage_flags( &attributes, PSA_KEY_USAGE_VERIFY_HASH );
+    psa_set_key_algorithm( &attributes, psa_sig_md );
+
+    ret = mbedtls_ecp_point_write_binary(&ctx->grp, &ctx->Q,
+                                         MBEDTLS_ECP_PF_UNCOMPRESSED,
+                                         &key_len, buf, sizeof(buf));
+    if (ret != 0) {
+        goto cleanup;
     }
 
-    psa_set_key_type(&attributes, PSA_KEY_TYPE_ECC_PUBLIC_KEY(curve));
-    psa_set_key_usage_flags(&attributes, PSA_KEY_USAGE_VERIFY_HASH);
-    psa_set_key_algorithm(&attributes, psa_sig_md);
-
     status = psa_import_key(&attributes,
-                            buf + sizeof(buf) - key_len, key_len,
+                            buf, key_len,
                             &key_id);
     if (status != PSA_SUCCESS) {
-        ret = mbedtls_pk_error_from_psa(status);
+        ret = mbedtls_pk_error_from_psa( status );
         goto cleanup;
     }