diff --git a/library/ecjpake.c b/library/ecjpake.c
index 9e074c9..f56142c 100644
--- a/library/ecjpake.c
+++ b/library/ecjpake.c
@@ -185,7 +185,7 @@
                              const mbedtls_ecp_point *G,
                              const mbedtls_ecp_point *X,
                              const char *id,
-                             unsigned char **p,
+                             const unsigned char **p,
                              const unsigned char *end )
 {
     int ret;
@@ -207,8 +207,7 @@
     if( end < *p )
         return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
 
-    MBEDTLS_MPI_CHK( mbedtls_ecp_tls_read_point( grp, &V,
-                     (const unsigned char **) p, end - *p ) );
+    MBEDTLS_MPI_CHK( mbedtls_ecp_tls_read_point( grp, &V, p, end - *p ) );
 
     if( end < *p || (size_t)( end - *p ) < 1 )
     {
@@ -217,6 +216,7 @@
     }
 
     r_len = *(*p)++;
+
     if( end < *p || (size_t)( end - *p ) < r_len )
     {
         ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
@@ -257,7 +257,7 @@
                              const mbedtls_ecp_point *G,
                              mbedtls_ecp_point *X,
                              const char *id,
-                             unsigned char **p,
+                             const unsigned char **p,
                              const unsigned char *end )
 {
     int ret;
@@ -271,8 +271,7 @@
      *     ECSchnorrZKP zkp;
      * } ECJPAKEKeyKP;
      */
-    MBEDTLS_MPI_CHK( mbedtls_ecp_tls_read_point( grp, X,
-                    (const unsigned char **) p, end - *p ) );
+    MBEDTLS_MPI_CHK( mbedtls_ecp_tls_read_point( grp, X, p, end - *p ) );
     MBEDTLS_MPI_CHK( ecjpake_zkp_read( md_info, grp, G, X, id, p, end ) );
 
 cleanup:
@@ -329,7 +328,7 @@
                               size_t len )
 {
     int ret;
-    unsigned char *p = (unsigned char *) buf;
+    const unsigned char *p = buf;
     const unsigned char *end = buf + len;
 
     /*