diff --git a/library/pkwrite.c b/library/pkwrite.c
index c75b48df7..87285f05d 100644
--- a/library/pkwrite.c
+++ b/library/pkwrite.c
@@ -473,10 +473,12 @@ int mbedtls_pk_write_key_der( const mbedtls_pk_context *key, unsigned char *buf,
 #define PEM_BEGIN_PRIVATE_KEY_EC    "-----BEGIN EC PRIVATE KEY-----\n"
 #define PEM_END_PRIVATE_KEY_EC      "-----END EC PRIVATE KEY-----\n"
 
-#define PUB_DER_MAX_BYTES   ( RSA_PUB_DER_MAX_BYTES > ECP_PUB_DER_MAX_BYTES ? \
-                              RSA_PUB_DER_MAX_BYTES : ECP_PUB_DER_MAX_BYTES )
-#define PRV_DER_MAX_BYTES   ( RSA_PRV_DER_MAX_BYTES > ECP_PRV_DER_MAX_BYTES ? \
-                              RSA_PRV_DER_MAX_BYTES : ECP_PRV_DER_MAX_BYTES )
+#define PUB_DER_MAX_BYTES                                                   \
+    ( MBEDTLS_PK_RSA_PUB_DER_MAX_BYTES > MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES ? \
+      MBEDTLS_PK_RSA_PUB_DER_MAX_BYTES : MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES )
+#define PRV_DER_MAX_BYTES                                                   \
+    ( MBEDTLS_PK_RSA_PRV_DER_MAX_BYTES > MBEDTLS_PK_ECP_PRV_DER_MAX_BYTES ? \
+      MBEDTLS_PK_RSA_PRV_DER_MAX_BYTES : MBEDTLS_PK_ECP_PRV_DER_MAX_BYTES )
 
 int mbedtls_pk_write_pubkey_pem( const mbedtls_pk_context *key, unsigned char *buf, size_t size )
 {
diff --git a/library/pkwrite.h b/library/pkwrite.h
index a3fd6ad7e..77d3b9183 100644
--- a/library/pkwrite.h
+++ b/library/pkwrite.h
@@ -44,7 +44,7 @@
  *      publicExponent    INTEGER   -- e            1 + 3 + MPI_MAX + 1
  *  }
  */
-#define RSA_PUB_DER_MAX_BYTES   ( 38 + 2 * MBEDTLS_MPI_MAX_SIZE )
+#define MBEDTLS_PK_RSA_PUB_DER_MAX_BYTES    ( 38 + 2 * MBEDTLS_MPI_MAX_SIZE )
 
 /*
  * RSA private keys:
@@ -61,15 +61,15 @@
  *      otherPrimeInfos   OtherPrimeInfos OPTIONAL  0 (not supported)
  *  }
  */
-#define MPI_MAX_SIZE_2          ( MBEDTLS_MPI_MAX_SIZE / 2 + \
+#define MBEDTLS_MPI_MAX_SIZE_2  ( MBEDTLS_MPI_MAX_SIZE / 2 + \
                                   MBEDTLS_MPI_MAX_SIZE % 2 )
-#define RSA_PRV_DER_MAX_BYTES   ( 47 + 3 * MBEDTLS_MPI_MAX_SIZE \
-                                   + 5 * MPI_MAX_SIZE_2 )
+#define MBEDTLS_PK_RSA_PRV_DER_MAX_BYTES    ( 47 + 3 * MBEDTLS_MPI_MAX_SIZE \
+                                              + 5 * MBEDTLS_MPI_MAX_SIZE_2 )
 
 #else /* MBEDTLS_RSA_C */
 
-#define RSA_PUB_DER_MAX_BYTES   0
-#define RSA_PRV_DER_MAX_BYTES   0
+#define MBEDTLS_PK_RSA_PUB_DER_MAX_BYTES   0
+#define MBEDTLS_PK_RSA_PRV_DER_MAX_BYTES   0
 
 #endif /* MBEDTLS_RSA_C */
 
@@ -85,7 +85,7 @@
  *                                            + 2 * ECP_MAX (coords)    [1]
  *  }
  */
-#define ECP_PUB_DER_MAX_BYTES   ( 30 + 2 * MBEDTLS_ECP_MAX_BYTES )
+#define MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES    ( 30 + 2 * MBEDTLS_ECP_MAX_BYTES )
 
 /*
  * EC private keys:
@@ -96,12 +96,12 @@
  *      publicKey  [1] BIT STRING OPTIONAL      1 + 2 + [1] above
  *    }
  */
-#define ECP_PRV_DER_MAX_BYTES   ( 29 + 3 * MBEDTLS_ECP_MAX_BYTES )
+#define MBEDTLS_PK_ECP_PRV_DER_MAX_BYTES    ( 29 + 3 * MBEDTLS_ECP_MAX_BYTES )
 
 #else /* MBEDTLS_ECP_C */
 
-#define ECP_PUB_DER_MAX_BYTES   0
-#define ECP_PRV_DER_MAX_BYTES   0
+#define MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES   0
+#define MBEDTLS_PK_ECP_PRV_DER_MAX_BYTES   0
 
 #endif /* MBEDTLS_ECP_C */