diff --git a/library/ecjpake.c b/library/ecjpake.c
index fb13a39..cdf5d7e 100644
--- a/library/ecjpake.c
+++ b/library/ecjpake.c
@@ -168,7 +168,7 @@
     }
 
     ret = mbedtls_ecp_point_write_binary(grp, P, pf,
-                                         &len, *p + 4, end - (*p + 4));
+                                         &len, *p + 4, (size_t) (end - (*p + 4)));
     if (ret != 0) {
         return ret;
     }
@@ -226,7 +226,7 @@
 
     /* Compute hash */
     MBEDTLS_MPI_CHK(mbedtls_ecjpake_compute_hash(md_type,
-                                                 buf, p - buf, hash));
+                                                 buf, (size_t) (p - buf), hash));
 
     /* Turn it into an integer mod n */
     MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(h, hash,
@@ -269,7 +269,7 @@
         return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
     }
 
-    MBEDTLS_MPI_CHK(mbedtls_ecp_tls_read_point(grp, &V, p, end - *p));
+    MBEDTLS_MPI_CHK(mbedtls_ecp_tls_read_point(grp, &V, p, (size_t) (end - *p)));
 
     if (end < *p || (size_t) (end - *p) < 1) {
         ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
@@ -346,7 +346,7 @@
 
     /* Write it out */
     MBEDTLS_MPI_CHK(mbedtls_ecp_tls_write_point(grp, &V,
-                                                pf, &len, *p, end - *p));
+                                                pf, &len, *p, (size_t) (end - *p)));
     *p += len;
 
     len = mbedtls_mpi_size(&h);   /* actually r */
@@ -392,7 +392,7 @@
      *     ECSchnorrZKP zkp;
      * } ECJPAKEKeyKP;
      */
-    MBEDTLS_MPI_CHK(mbedtls_ecp_tls_read_point(grp, X, p, end - *p));
+    MBEDTLS_MPI_CHK(mbedtls_ecp_tls_read_point(grp, X, p, (size_t) (end - *p)));
     if (mbedtls_ecp_is_zero(X)) {
         ret = MBEDTLS_ERR_ECP_INVALID_KEY;
         goto cleanup;
@@ -431,7 +431,7 @@
     MBEDTLS_MPI_CHK(mbedtls_ecp_gen_keypair_base((mbedtls_ecp_group *) grp, G, x, X,
                                                  f_rng, p_rng));
     MBEDTLS_MPI_CHK(mbedtls_ecp_tls_write_point(grp, X,
-                                                pf, &len, *p, end - *p));
+                                                pf, &len, *p, (size_t) (end - *p)));
     *p += len;
 
     /* Generate and write proof */
@@ -504,7 +504,7 @@
     MBEDTLS_MPI_CHK(ecjpake_kkp_write(md_type, grp, pf, G, xm2, Xb, id,
                                       &p, end, f_rng, p_rng));
 
-    *olen = p - buf;
+    *olen = (size_t) (p - buf);
 
 cleanup:
     return ret;
@@ -693,7 +693,7 @@
             goto cleanup;
         }
         MBEDTLS_MPI_CHK(mbedtls_ecp_tls_write_group(&ctx->grp, &ec_len,
-                                                    p, end - p));
+                                                    p, (size_t) (end - p)));
         p += ec_len;
     }
 
@@ -702,7 +702,7 @@
         goto cleanup;
     }
     MBEDTLS_MPI_CHK(mbedtls_ecp_tls_write_point(&ctx->grp, &Xm,
-                                                ctx->point_format, &ec_len, p, end - p));
+                                                ctx->point_format, &ec_len, p, (size_t) (end - p)));
     p += ec_len;
 
     MBEDTLS_MPI_CHK(ecjpake_zkp_write(ctx->md_type, &ctx->grp,
@@ -710,7 +710,7 @@
                                       &G, &xm, &Xm, ID_MINE,
                                       &p, end, f_rng, p_rng));
 
-    *olen = p - buf;
+    *olen = (size_t) (p - buf);
 
 cleanup:
     mbedtls_ecp_point_free(&G);