diff --git a/library/aesce.c b/library/aesce.c
index 93c8f28..2835398 100644
--- a/library/aesce.c
+++ b/library/aesce.c
@@ -309,7 +309,7 @@
          rki + key_len_in_words < rko_end;
          rki += key_len_in_words) {
 
-        size_t iteration = (rki - (uint32_t *) rk) / key_len_in_words;
+        size_t iteration = (size_t) (rki - (uint32_t *) rk) / key_len_in_words;
         uint32_t *rko;
         rko = rki + key_len_in_words;
         rko[0] = aes_rot_word(aes_sub_word(rki[key_len_in_words - 1]));
@@ -394,8 +394,8 @@
 
     return vreinterpretq_u8_p128(
         MBEDTLS_VMULL_P64(
-            vget_low_p64(vreinterpretq_p64_u8(a)),
-            vget_low_p64(vreinterpretq_p64_u8(b))
+            (poly64_t) vget_low_p64(vreinterpretq_p64_u8(a)),
+            (poly64_t) vget_low_p64(vreinterpretq_p64_u8(b))
             ));
 }
 
diff --git a/library/base64.c b/library/base64.c
index a58717d..9677dee 100644
--- a/library/base64.c
+++ b/library/base64.c
@@ -116,7 +116,7 @@
         *p++ = '=';
     }
 
-    *olen = p - dst;
+    *olen = (size_t) (p - dst);
     *p = 0;
 
     return 0;
@@ -225,7 +225,7 @@
         }
     }
 
-    *olen = p - dst;
+    *olen = (size_t) (p - dst);
 
     return 0;
 }
diff --git a/library/bignum.c b/library/bignum.c
index 09ce030..1b7ff58 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -701,7 +701,7 @@
     }
 
     *p++ = '\0';
-    *olen = p - buf;
+    *olen = (size_t) (p - buf);
 
 cleanup:
 
diff --git a/library/debug.c b/library/debug.c
index c7bbd41..a9d58e5 100644
--- a/library/debug.c
+++ b/library/debug.c
@@ -366,7 +366,7 @@
     start = text;
     for (cur = text; *cur != '\0'; cur++) {
         if (*cur == '\n') {
-            size_t len = cur - start + 1;
+            size_t len = (size_t) (cur - start) + 1;
             if (len > DEBUG_BUF_SIZE - 1) {
                 len = DEBUG_BUF_SIZE - 1;
             }
diff --git a/library/dhm.c b/library/dhm.c
index 3daf0c2..bcc07f5 100644
--- a/library/dhm.c
+++ b/library/dhm.c
@@ -48,10 +48,10 @@
         return MBEDTLS_ERR_DHM_BAD_INPUT_DATA;
     }
 
-    n = ((*p)[0] << 8) | (*p)[1];
+    n = MBEDTLS_GET_UINT16_BE(*p, 0);
     (*p) += 2;
 
-    if ((int) (end - *p) < n) {
+    if ((size_t) (end - *p) < (size_t) n) {
         return MBEDTLS_ERR_DHM_BAD_INPUT_DATA;
     }
 
@@ -257,7 +257,7 @@
     DHM_MPI_EXPORT(&ctx->G, n2);
     DHM_MPI_EXPORT(&ctx->GX, n3);
 
-    *olen = p - output;
+    *olen = (size_t) (p - output);
 
 cleanup:
     if (ret != 0 && ret > -128) {
diff --git a/library/ecdh.c b/library/ecdh.c
index e060b18..52b1617 100644
--- a/library/ecdh.c
+++ b/library/ecdh.c
@@ -363,7 +363,7 @@
                                      const unsigned char *end)
 {
     return mbedtls_ecp_tls_read_point(&ctx->grp, &ctx->Qp, buf,
-                                      end - *buf);
+                                      (size_t) (end - *buf));
 }
 
 /*
@@ -379,7 +379,7 @@
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_ecp_group_id grp_id;
-    if ((ret = mbedtls_ecp_tls_read_group_id(&grp_id, buf, end - *buf))
+    if ((ret = mbedtls_ecp_tls_read_group_id(&grp_id, buf, (size_t) (end - *buf)))
         != 0) {
         return ret;
     }
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);
diff --git a/library/entropy_poll.c b/library/entropy_poll.c
index e8c669f..de2e038 100644
--- a/library/entropy_poll.c
+++ b/library/entropy_poll.c
@@ -88,7 +88,7 @@
     memset(buf, 0, buflen);
 #endif
 #endif
-    return syscall(SYS_getrandom, buf, buflen, flags);
+    return (int) syscall(SYS_getrandom, buf, buflen, flags);
 }
 #endif /* SYS_getrandom */
 #endif /* __linux__ || __midipix__ */
@@ -102,7 +102,7 @@
 #define HAVE_GETRANDOM
 static int getrandom_wrapper(void *buf, size_t buflen, unsigned int flags)
 {
-    return getrandom(buf, buflen, flags);
+    return (int) getrandom(buf, buflen, flags);
 }
 #endif /* (__FreeBSD__ && __FreeBSD_version >= 1200000) ||
           (__DragonFly__ && __DragonFly_version >= 500700) */
@@ -156,7 +156,7 @@
 #if defined(HAVE_GETRANDOM)
     ret = getrandom_wrapper(output, len, 0);
     if (ret >= 0) {
-        *olen = ret;
+        *olen = (size_t) ret;
         return 0;
     } else if (errno != ENOSYS) {
         return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
diff --git a/library/lmots.c b/library/lmots.c
index e09e3e5..c7091b4 100644
--- a/library/lmots.c
+++ b/library/lmots.c
@@ -69,29 +69,6 @@
 int (*mbedtls_lmots_sign_private_key_invalidated_hook)(unsigned char *) = NULL;
 #endif /* defined(MBEDTLS_TEST_HOOKS) */
 
-void mbedtls_lms_unsigned_int_to_network_bytes(unsigned int val, size_t len,
-                                               unsigned char *bytes)
-{
-    size_t idx;
-
-    for (idx = 0; idx < len; idx++) {
-        bytes[idx] = (val >> ((len - 1 - idx) * 8)) & 0xFF;
-    }
-}
-
-unsigned int mbedtls_lms_network_bytes_to_unsigned_int(size_t len,
-                                                       const unsigned char *bytes)
-{
-    size_t idx;
-    unsigned int val = 0;
-
-    for (idx = 0; idx < len; idx++) {
-        val |= ((unsigned int) bytes[idx]) << (8 * (len - 1 - idx));
-    }
-
-    return val;
-}
-
 /* Calculate the checksum digits that are appended to the end of the LMOTS digit
  * string. See NIST SP800-208 section 3.1 or RFC8554 Algorithm 2 for details of
  * the checksum algorithm.
@@ -191,8 +168,7 @@
     }
 
     checksum = lmots_checksum_calculate(params, out);
-    mbedtls_lms_unsigned_int_to_network_bytes(checksum, CHECKSUM_LEN,
-                                              out + MBEDTLS_LMOTS_N_HASH_LEN(params->type));
+    MBEDTLS_PUT_UINT16_BE(checksum, out, MBEDTLS_LMOTS_N_HASH_LEN(params->type));
 
 exit:
     psa_hash_abort(&op);
@@ -281,17 +257,13 @@
                 goto exit;
             }
 
-            mbedtls_lms_unsigned_int_to_network_bytes(i_digit_idx,
-                                                      I_DIGIT_IDX_LEN,
-                                                      i_digit_idx_bytes);
+            MBEDTLS_PUT_UINT16_BE(i_digit_idx, i_digit_idx_bytes, 0);
             status = psa_hash_update(&op, i_digit_idx_bytes, I_DIGIT_IDX_LEN);
             if (status != PSA_SUCCESS) {
                 goto exit;
             }
 
-            mbedtls_lms_unsigned_int_to_network_bytes(j_hash_idx,
-                                                      J_HASH_IDX_LEN,
-                                                      j_hash_idx_bytes);
+            j_hash_idx_bytes[0] = (uint8_t) j_hash_idx;
             status = psa_hash_update(&op, j_hash_idx_bytes, J_HASH_IDX_LEN);
             if (status != PSA_SUCCESS) {
                 goto exit;
@@ -425,11 +397,8 @@
         return MBEDTLS_ERR_LMS_BAD_INPUT_DATA;
     }
 
-    ctx->params.type =
-        (mbedtls_lmots_algorithm_type_t) mbedtls_lms_network_bytes_to_unsigned_int(
-            MBEDTLS_LMOTS_TYPE_LEN,
-            key +
-            MBEDTLS_LMOTS_SIG_TYPE_OFFSET);
+    ctx->params.type = (mbedtls_lmots_algorithm_type_t)
+                       MBEDTLS_GET_UINT32_BE(key, MBEDTLS_LMOTS_SIG_TYPE_OFFSET);
 
     if (key_len != MBEDTLS_LMOTS_PUBLIC_KEY_LEN(ctx->params.type)) {
         return MBEDTLS_ERR_LMS_BAD_INPUT_DATA;
@@ -464,9 +433,7 @@
         return MBEDTLS_ERR_LMS_BAD_INPUT_DATA;
     }
 
-    mbedtls_lms_unsigned_int_to_network_bytes(ctx->params.type,
-                                              MBEDTLS_LMOTS_TYPE_LEN,
-                                              key + MBEDTLS_LMOTS_SIG_TYPE_OFFSET);
+    MBEDTLS_PUT_UINT32_BE(ctx->params.type, key, MBEDTLS_LMOTS_SIG_TYPE_OFFSET);
 
     memcpy(key + PUBLIC_KEY_I_KEY_ID_OFFSET,
            ctx->params.I_key_identifier,
@@ -559,9 +526,7 @@
         return MBEDTLS_ERR_LMS_VERIFY_FAILED;
     }
 
-    if (mbedtls_lms_network_bytes_to_unsigned_int(MBEDTLS_LMOTS_TYPE_LEN,
-                                                  sig + MBEDTLS_LMOTS_SIG_TYPE_OFFSET) !=
-        MBEDTLS_LMOTS_SHA256_N32_W8) {
+    if (MBEDTLS_GET_UINT32_BE(sig, MBEDTLS_LMOTS_SIG_TYPE_OFFSET) != MBEDTLS_LMOTS_SHA256_N32_W8) {
         return MBEDTLS_ERR_LMS_VERIFY_FAILED;
     }
 
@@ -607,7 +572,7 @@
     size_t output_hash_len;
     unsigned int i_digit_idx;
     unsigned char i_digit_idx_bytes[2];
-    unsigned char const_bytes[1];
+    unsigned char const_bytes[1] = { 0xFF };
 
     if (ctx->have_private_key) {
         return MBEDTLS_ERR_LMS_BAD_INPUT_DATA;
@@ -623,12 +588,7 @@
            I_key_identifier,
            sizeof(ctx->params.I_key_identifier));
 
-    mbedtls_lms_unsigned_int_to_network_bytes(q_leaf_identifier,
-                                              MBEDTLS_LMOTS_Q_LEAF_ID_LEN,
-                                              ctx->params.q_leaf_identifier);
-
-    mbedtls_lms_unsigned_int_to_network_bytes(0xFF, sizeof(const_bytes),
-                                              const_bytes);
+    MBEDTLS_PUT_UINT32_BE(q_leaf_identifier, ctx->params.q_leaf_identifier, 0);
 
     for (i_digit_idx = 0;
          i_digit_idx < MBEDTLS_LMOTS_P_SIG_DIGIT_COUNT(ctx->params.type);
@@ -652,8 +612,7 @@
             goto exit;
         }
 
-        mbedtls_lms_unsigned_int_to_network_bytes(i_digit_idx, I_DIGIT_IDX_LEN,
-                                                  i_digit_idx_bytes);
+        MBEDTLS_PUT_UINT16_BE(i_digit_idx, i_digit_idx_bytes, 0);
         status = psa_hash_update(&op, i_digit_idx_bytes, I_DIGIT_IDX_LEN);
         if (status != PSA_SUCCESS) {
             goto exit;
@@ -774,9 +733,7 @@
         goto exit;
     }
 
-    mbedtls_lms_unsigned_int_to_network_bytes(ctx->params.type,
-                                              MBEDTLS_LMOTS_TYPE_LEN,
-                                              sig + MBEDTLS_LMOTS_SIG_TYPE_OFFSET);
+    MBEDTLS_PUT_UINT32_BE(ctx->params.type, sig, MBEDTLS_LMOTS_SIG_TYPE_OFFSET);
 
     /* Test hook to check if sig is being written to before we invalidate the
      * private key.
diff --git a/library/lmots.h b/library/lmots.h
index 8e495c9..cf92d32 100644
--- a/library/lmots.h
+++ b/library/lmots.h
@@ -44,29 +44,6 @@
 extern int (*mbedtls_lmots_sign_private_key_invalidated_hook)(unsigned char *);
 #endif /* defined(MBEDTLS_TEST_HOOKS) */
 
-/**
- * \brief                    This function converts an unsigned int into a
- *                           network-byte-order (big endian) string.
- *
- * \param val                The unsigned integer value
- * \param len                The length of the string.
- * \param bytes              The string to output into.
- */
-void mbedtls_lms_unsigned_int_to_network_bytes(unsigned int val, size_t len,
-                                               unsigned char *bytes);
-
-/**
- * \brief                    This function converts a network-byte-order
- *                           (big endian) string into an unsigned integer.
- *
- * \param len                The length of the string.
- * \param bytes              The string.
- *
- * \return                   The corresponding LMS error code.
- */
-unsigned int mbedtls_lms_network_bytes_to_unsigned_int(size_t len,
-                                                       const unsigned char *bytes);
-
 #if !defined(MBEDTLS_DEPRECATED_REMOVED)
 /**
  * \brief                    This function converts a \ref psa_status_t to a
diff --git a/library/lms.c b/library/lms.c
index 0c470a0..08fe753 100644
--- a/library/lms.c
+++ b/library/lms.c
@@ -112,7 +112,7 @@
         goto exit;
     }
 
-    mbedtls_lms_unsigned_int_to_network_bytes(r_node_idx, 4, r_node_idx_bytes);
+    MBEDTLS_PUT_UINT32_BE(r_node_idx, r_node_idx_bytes, 0);
     status = psa_hash_update(&op, r_node_idx_bytes, 4);
     if (status != PSA_SUCCESS) {
         goto exit;
@@ -186,7 +186,7 @@
         goto exit;
     }
 
-    mbedtls_lms_unsigned_int_to_network_bytes(r_node_idx, 4, r_node_idx_bytes);
+    MBEDTLS_PUT_UINT32_BE(r_node_idx, r_node_idx_bytes, 0);
     status = psa_hash_update(&op, r_node_idx_bytes, 4);
     if (status != PSA_SUCCESS) {
         goto exit;
@@ -237,10 +237,7 @@
     mbedtls_lms_algorithm_type_t type;
     mbedtls_lmots_algorithm_type_t otstype;
 
-    type = (mbedtls_lms_algorithm_type_t) mbedtls_lms_network_bytes_to_unsigned_int(
-        MBEDTLS_LMS_TYPE_LEN,
-        key +
-        PUBLIC_KEY_TYPE_OFFSET);
+    type = (mbedtls_lms_algorithm_type_t) MBEDTLS_GET_UINT32_BE(key, PUBLIC_KEY_TYPE_OFFSET);
     if (type != MBEDTLS_LMS_SHA256_M32_H10) {
         return MBEDTLS_ERR_LMS_BAD_INPUT_DATA;
     }
@@ -250,10 +247,8 @@
         return MBEDTLS_ERR_LMS_BAD_INPUT_DATA;
     }
 
-    otstype = (mbedtls_lmots_algorithm_type_t) mbedtls_lms_network_bytes_to_unsigned_int(
-        MBEDTLS_LMOTS_TYPE_LEN,
-        key +
-        PUBLIC_KEY_OTSTYPE_OFFSET);
+    otstype = (mbedtls_lmots_algorithm_type_t)
+              MBEDTLS_GET_UINT32_BE(key, PUBLIC_KEY_OTSTYPE_OFFSET);
     if (otstype != MBEDTLS_LMOTS_SHA256_N32_W8) {
         return MBEDTLS_ERR_LMS_BAD_INPUT_DATA;
     }
@@ -282,12 +277,8 @@
         return MBEDTLS_ERR_LMS_BAD_INPUT_DATA;
     }
 
-    mbedtls_lms_unsigned_int_to_network_bytes(
-        ctx->params.type,
-        MBEDTLS_LMS_TYPE_LEN, key + PUBLIC_KEY_TYPE_OFFSET);
-    mbedtls_lms_unsigned_int_to_network_bytes(ctx->params.otstype,
-                                              MBEDTLS_LMOTS_TYPE_LEN,
-                                              key + PUBLIC_KEY_OTSTYPE_OFFSET);
+    MBEDTLS_PUT_UINT32_BE(ctx->params.type, key, PUBLIC_KEY_TYPE_OFFSET);
+    MBEDTLS_PUT_UINT32_BE(ctx->params.otstype, key, PUBLIC_KEY_OTSTYPE_OFFSET);
     memcpy(key + PUBLIC_KEY_I_KEY_ID_OFFSET,
            ctx->params.I_key_identifier,
            MBEDTLS_LMOTS_I_KEY_ID_LEN);
@@ -339,9 +330,7 @@
         return MBEDTLS_ERR_LMS_VERIFY_FAILED;
     }
 
-    if (mbedtls_lms_network_bytes_to_unsigned_int(MBEDTLS_LMOTS_TYPE_LEN,
-                                                  sig + SIG_OTS_SIG_OFFSET +
-                                                  MBEDTLS_LMOTS_SIG_TYPE_OFFSET)
+    if (MBEDTLS_GET_UINT32_BE(sig, SIG_OTS_SIG_OFFSET + MBEDTLS_LMOTS_SIG_TYPE_OFFSET)
         != MBEDTLS_LMOTS_SHA256_N32_W8) {
         return MBEDTLS_ERR_LMS_VERIFY_FAILED;
     }
@@ -350,15 +339,13 @@
         return MBEDTLS_ERR_LMS_VERIFY_FAILED;
     }
 
-    if (mbedtls_lms_network_bytes_to_unsigned_int(MBEDTLS_LMS_TYPE_LEN,
-                                                  sig + SIG_TYPE_OFFSET(ctx->params.otstype))
+    if (MBEDTLS_GET_UINT32_BE(sig, SIG_TYPE_OFFSET(ctx->params.otstype))
         != MBEDTLS_LMS_SHA256_M32_H10) {
         return MBEDTLS_ERR_LMS_VERIFY_FAILED;
     }
 
 
-    q_leaf_identifier = mbedtls_lms_network_bytes_to_unsigned_int(
-        MBEDTLS_LMOTS_Q_LEAF_ID_LEN, sig + SIG_Q_LEAF_ID_OFFSET);
+    q_leaf_identifier = MBEDTLS_GET_UINT32_BE(sig, SIG_Q_LEAF_ID_OFFSET);
 
     if (q_leaf_identifier >= MERKLE_TREE_LEAF_NODE_AM(ctx->params.type)) {
         return MBEDTLS_ERR_LMS_VERIFY_FAILED;
@@ -367,9 +354,7 @@
     memcpy(ots_params.I_key_identifier,
            ctx->params.I_key_identifier,
            MBEDTLS_LMOTS_I_KEY_ID_LEN);
-    mbedtls_lms_unsigned_int_to_network_bytes(q_leaf_identifier,
-                                              MBEDTLS_LMOTS_Q_LEAF_ID_LEN,
-                                              ots_params.q_leaf_identifier);
+    MBEDTLS_PUT_UINT32_BE(q_leaf_identifier, ots_params.q_leaf_identifier, 0);
     ots_params.type = ctx->params.otstype;
 
     ret = mbedtls_lmots_calculate_public_key_candidate(&ots_params,
@@ -505,7 +490,7 @@
     unsigned int height;
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
-    tree = mbedtls_calloc(MERKLE_TREE_NODE_AM(ctx->params.type),
+    tree = mbedtls_calloc((size_t) MERKLE_TREE_NODE_AM(ctx->params.type),
                           node_bytes);
     if (tree == NULL) {
         return MBEDTLS_ERR_LMS_ALLOC_FAILED;
@@ -530,7 +515,7 @@
 
 exit:
     mbedtls_zeroize_and_free(tree, node_bytes *
-                             MERKLE_TREE_NODE_AM(ctx->params.type));
+                             (size_t) MERKLE_TREE_NODE_AM(ctx->params.type));
 
     return ret;
 }
@@ -669,7 +654,7 @@
         return MBEDTLS_ERR_LMS_BAD_INPUT_DATA;
     }
 
-    tree = mbedtls_calloc(MERKLE_TREE_NODE_AM(priv_ctx->params.type),
+    tree = mbedtls_calloc((size_t) MERKLE_TREE_NODE_AM(priv_ctx->params.type),
                           node_bytes);
     if (tree == NULL) {
         return MBEDTLS_ERR_LMS_ALLOC_FAILED;
@@ -692,7 +677,7 @@
 
 exit:
     mbedtls_zeroize_and_free(tree, node_bytes *
-                             MERKLE_TREE_NODE_AM(priv_ctx->params.type));
+                             (size_t) MERKLE_TREE_NODE_AM(priv_ctx->params.type));
 
     return ret;
 }
@@ -753,12 +738,8 @@
         return ret;
     }
 
-    mbedtls_lms_unsigned_int_to_network_bytes(ctx->params.type,
-                                              MBEDTLS_LMS_TYPE_LEN,
-                                              sig + SIG_TYPE_OFFSET(ctx->params.otstype));
-    mbedtls_lms_unsigned_int_to_network_bytes(q_leaf_identifier,
-                                              MBEDTLS_LMOTS_Q_LEAF_ID_LEN,
-                                              sig + SIG_Q_LEAF_ID_OFFSET);
+    MBEDTLS_PUT_UINT32_BE(ctx->params.type, sig, SIG_TYPE_OFFSET(ctx->params.otstype));
+    MBEDTLS_PUT_UINT32_BE(q_leaf_identifier, sig, SIG_Q_LEAF_ID_OFFSET);
 
     ret = get_merkle_path(ctx,
                           MERKLE_TREE_INTERNAL_NODE_AM(ctx->params.type) + q_leaf_identifier,
diff --git a/library/oid.c b/library/oid.c
index 6184abe..d8339c1 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -1129,7 +1129,7 @@
         }
     }
 
-    encoded_len = out_ptr - oid->p;
+    encoded_len = (size_t) (out_ptr - oid->p);
     resized_mem = mbedtls_calloc(encoded_len, 1);
     if (resized_mem == NULL) {
         ret = MBEDTLS_ERR_ASN1_ALLOC_FAILED;
diff --git a/library/pem.c b/library/pem.c
index 9500ffc..539134c 100644
--- a/library/pem.c
+++ b/library/pem.c
@@ -298,7 +298,7 @@
     if (*end == '\n') {
         end++;
     }
-    *use_len = end - data;
+    *use_len = (size_t) (end - data);
 
     enc = 0;
 
@@ -383,7 +383,7 @@
         return MBEDTLS_ERR_PEM_INVALID_DATA;
     }
 
-    ret = mbedtls_base64_decode(NULL, 0, &len, s1, s2 - s1);
+    ret = mbedtls_base64_decode(NULL, 0, &len, s1, (size_t) (s2 - s1));
 
     if (ret == MBEDTLS_ERR_BASE64_INVALID_CHARACTER) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PEM_INVALID_DATA, ret);
@@ -393,7 +393,7 @@
         return MBEDTLS_ERR_PEM_ALLOC_FAILED;
     }
 
-    if ((ret = mbedtls_base64_decode(buf, len, &len, s1, s2 - s1)) != 0) {
+    if ((ret = mbedtls_base64_decode(buf, len, &len, s1, (size_t) (s2 - s1))) != 0) {
         mbedtls_zeroize_and_free(buf, len);
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PEM_INVALID_DATA, ret);
     }
@@ -508,7 +508,7 @@
     p += strlen(footer);
 
     *p++ = '\0';
-    *olen = p - buf;
+    *olen = (size_t) (p - buf);
 
     /* Clean any remaining data previously written to the buffer */
     memset(buf + *olen, 0, buf_len - *olen);
diff --git a/library/pkcs7.c b/library/pkcs7.c
index 36b49f5..0869c2e 100644
--- a/library/pkcs7.c
+++ b/library/pkcs7.c
@@ -316,7 +316,7 @@
         goto out;
     }
 
-    signer->issuer_raw.len =  *p - signer->issuer_raw.p;
+    signer->issuer_raw.len =  (size_t) (*p - signer->issuer_raw.p);
 
     ret = mbedtls_x509_get_serial(p, end_issuer_and_sn, &signer->serial);
     if (ret != 0) {
diff --git a/library/pkparse.c b/library/pkparse.c
index 3bb5f7b..edebf92 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -928,7 +928,7 @@
             ret = pk_use_ecparams(&alg_params, pk);
         }
         if (ret == 0) {
-            ret = pk_ecc_set_pubkey(pk, *p, end - *p);
+            ret = pk_ecc_set_pubkey(pk, *p, (size_t) (end - *p));
             *p += end - *p;
         }
     } else
@@ -1233,7 +1233,7 @@
                                          MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
             }
 
-            if ((ret = pk_ecc_set_pubkey(pk, p, end2 - p)) == 0) {
+            if ((ret = pk_ecc_set_pubkey(pk, p, (size_t) (end2 - p))) == 0) {
                 pubkey_done = 1;
             } else {
                 /*
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 49dd915..1149940 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -6627,7 +6627,7 @@
     memcpy(cur, data, data_length);
     cur += data_length;
 
-    status = psa_tls12_prf_set_key(prf, pms, cur - pms);
+    status = psa_tls12_prf_set_key(prf, pms, (size_t) (cur - pms));
 
     mbedtls_zeroize_and_free(pms, pms_len);
     return status;
diff --git a/library/psa_its_file.c b/library/psa_its_file.c
index 3f32d7d..9567137 100644
--- a/library/psa_its_file.c
+++ b/library/psa_its_file.c
@@ -98,14 +98,9 @@
         return PSA_ERROR_DATA_CORRUPT;
     }
 
-    p_info->size = (header.size[0] |
-                    header.size[1] << 8 |
-                    header.size[2] << 16 |
-                    header.size[3] << 24);
-    p_info->flags = (header.flags[0] |
-                     header.flags[1] << 8 |
-                     header.flags[2] << 16 |
-                     header.flags[3] << 24);
+    p_info->size  = MBEDTLS_GET_UINT32_LE(header.size, 0);
+    p_info->flags = MBEDTLS_GET_UINT32_LE(header.flags, 0);
+
     return PSA_SUCCESS;
 }
 
diff --git a/library/rsa.c b/library/rsa.c
index 38c3dd6..1bf5d13 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -1620,12 +1620,12 @@
         goto cleanup;
     }
 
-    if (ilen - (p - buf) > output_max_len) {
+    if (ilen - ((size_t) (p - buf)) > output_max_len) {
         ret = MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE;
         goto cleanup;
     }
 
-    *olen = ilen - (p - buf);
+    *olen = ilen - ((size_t) (p - buf));
     if (*olen != 0) {
         memcpy(output, p, *olen);
     }
@@ -2191,7 +2191,7 @@
         return MBEDTLS_ERR_RSA_INVALID_PADDING;
     }
 
-    observed_salt_len = hash_start - p;
+    observed_salt_len = (size_t) (hash_start - p);
 
     if (expected_salt_len != MBEDTLS_RSA_SALT_LEN_ANY &&
         observed_salt_len != (size_t) expected_salt_len) {
diff --git a/library/ssl_client.c b/library/ssl_client.c
index 8d25e69..55fe352 100644
--- a/library/ssl_client.c
+++ b/library/ssl_client.c
@@ -155,7 +155,7 @@
         p += protocol_name_len;
     }
 
-    *out_len = p - buf;
+    *out_len = (size_t) (p - buf);
 
     /* List length = *out_len - 2 (ext_type) - 2 (ext_len) - 2 (list_len) */
     MBEDTLS_PUT_UINT16_BE(*out_len - 6, buf, 4);
@@ -285,7 +285,7 @@
     }
 
     /* Length of named_group_list */
-    named_group_list_len = p - named_group_list;
+    named_group_list_len = (size_t) (p - named_group_list);
     if (named_group_list_len == 0) {
         MBEDTLS_SSL_DEBUG_MSG(1, ("No group available."));
         return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
@@ -301,7 +301,7 @@
     MBEDTLS_SSL_DEBUG_BUF(3, "Supported groups extension",
                           buf + 4, named_group_list_len + 2);
 
-    *out_len = p - buf;
+    *out_len = (size_t) (p - buf);
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_3)
     mbedtls_ssl_tls13_set_hs_sent_ext_mask(
@@ -391,14 +391,14 @@
     }
 
     /* Write the cipher_suites length in number of bytes */
-    cipher_suites_len = p - cipher_suites;
+    cipher_suites_len = (size_t) (p - cipher_suites);
     MBEDTLS_PUT_UINT16_BE(cipher_suites_len, buf, 0);
     MBEDTLS_SSL_DEBUG_MSG(3,
                           ("client hello, got %" MBEDTLS_PRINTF_SIZET " cipher suites",
                            cipher_suites_len/2));
 
     /* Output the total length of cipher_suites field. */
-    *out_len = p - buf;
+    *out_len = (size_t) (p - buf);
 
     return 0;
 }
@@ -679,7 +679,7 @@
 #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED */
 
     /* Write the length of the list of extensions. */
-    extensions_len = p - p_extensions_len - 2;
+    extensions_len = (size_t) (p - p_extensions_len) - 2;
 
     if (extensions_len == 0) {
         p = p_extensions_len;
@@ -691,7 +691,7 @@
                               p_extensions_len, extensions_len);
     }
 
-    *out_len = p - buf;
+    *out_len = (size_t) (p - buf);
     return 0;
 }
 
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index c636ad4..eae192b 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1409,7 +1409,7 @@
  * Write handshake message header
  */
 MBEDTLS_CHECK_RETURN_CRITICAL
-int mbedtls_ssl_start_handshake_msg(mbedtls_ssl_context *ssl, unsigned hs_type,
+int mbedtls_ssl_start_handshake_msg(mbedtls_ssl_context *ssl, unsigned char hs_type,
                                     unsigned char **buf, size_t *buf_len);
 
 MBEDTLS_CHECK_RETURN_CRITICAL
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index cffd1c9..48d0a03 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -848,7 +848,7 @@
         cur += 2;
     }
 
-    *add_data_len = cur - add_data;
+    *add_data_len = (size_t) (cur - add_data);
 }
 
 #if defined(MBEDTLS_SSL_HAVE_AEAD)
@@ -1212,7 +1212,7 @@
                                                    iv, transform->ivlen,
                                                    add_data, add_data_len,
                                                    data, rec->data_len, /* src */
-                                                   data, rec->buf_len - (data - rec->buf), /* dst */
+                                                   data, rec->buf_len - (size_t) (data - rec->buf), /* dst */
                                                    &rec->data_len,
                                                    transform->taglen)) != 0) {
             MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_cipher_auth_encrypt_ext", ret);
@@ -1635,12 +1635,13 @@
             return ret;
         }
 #else
-        if ((ret = mbedtls_cipher_auth_decrypt_ext(&transform->cipher_ctx_dec,
-                                                   iv, transform->ivlen,
-                                                   add_data, add_data_len,
-                                                   data, rec->data_len + transform->taglen, /* src */
-                                                   data, rec->buf_len - (data - rec->buf), &olen, /* dst */
-                                                   transform->taglen)) != 0) {
+        if ((ret = mbedtls_cipher_auth_decrypt_ext
+                       (&transform->cipher_ctx_dec,
+                       iv, transform->ivlen,
+                       add_data, add_data_len,
+                       data, rec->data_len + transform->taglen, /* src */
+                       data, rec->buf_len - (size_t) (data - rec->buf), &olen, /* dst */
+                       transform->taglen)) != 0) {
             MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_cipher_auth_decrypt_ext", ret);
 
             if (ret == MBEDTLS_ERR_CIPHER_AUTH_FAILED) {
@@ -2228,7 +2229,7 @@
             MBEDTLS_SSL_DEBUG_MSG(2, ("timer has expired"));
             ret = MBEDTLS_ERR_SSL_TIMEOUT;
         } else {
-            len = in_buf_len - (ssl->in_hdr - ssl->in_buf);
+            len = in_buf_len - (size_t) (ssl->in_hdr - ssl->in_buf);
 
             if (mbedtls_ssl_is_handshake_over(ssl) == 0) {
                 timeout = ssl->handshake->retransmit_timeout;
@@ -2592,7 +2593,7 @@
         } else {
             const unsigned char * const p = ssl->handshake->cur_msg_p;
             const size_t hs_len = cur->len - 12;
-            const size_t frag_off = p - (cur->p + 12);
+            const size_t frag_off = (size_t) (p - (cur->p + 12));
             const size_t rem_len = hs_len - frag_off;
             size_t cur_hs_frag_len, max_hs_frag_len;
 
@@ -2730,7 +2731,7 @@
 /*
  * Handshake layer functions
  */
-int mbedtls_ssl_start_handshake_msg(mbedtls_ssl_context *ssl, unsigned hs_type,
+int mbedtls_ssl_start_handshake_msg(mbedtls_ssl_context *ssl, unsigned char hs_type,
                                     unsigned char **buf, size_t *buf_len)
 {
     /*
@@ -2969,9 +2970,9 @@
             mbedtls_record rec;
 
             rec.buf         = ssl->out_iv;
-            rec.buf_len     = out_buf_len - (ssl->out_iv - ssl->out_buf);
+            rec.buf_len     = out_buf_len - (size_t) (ssl->out_iv - ssl->out_buf);
             rec.data_len    = ssl->out_msglen;
-            rec.data_offset = ssl->out_msg - rec.buf;
+            rec.data_offset = (size_t) (ssl->out_msg - rec.buf);
 
             memcpy(&rec.ctr[0], ssl->out_ctr, sizeof(rec.ctr));
             mbedtls_ssl_write_version(rec.ver, ssl->conf->transport, tls_ver);
@@ -3096,16 +3097,12 @@
 
 static uint32_t ssl_get_hs_frag_len(mbedtls_ssl_context const *ssl)
 {
-    return (ssl->in_msg[9] << 16) |
-           (ssl->in_msg[10] << 8) |
-           ssl->in_msg[11];
+    return MBEDTLS_GET_UINT24_BE(ssl->in_msg, 9);
 }
 
 static uint32_t ssl_get_hs_frag_off(mbedtls_ssl_context const *ssl)
 {
-    return (ssl->in_msg[6] << 16) |
-           (ssl->in_msg[7] << 8) |
-           ssl->in_msg[8];
+    return MBEDTLS_GET_UINT24_BE(ssl->in_msg, 6);
 }
 
 MBEDTLS_CHECK_RETURN_CRITICAL
@@ -3218,9 +3215,7 @@
 
 static uint32_t ssl_get_hs_total_len(mbedtls_ssl_context const *ssl)
 {
-    return (ssl->in_msg[1] << 16) |
-           (ssl->in_msg[2] << 8) |
-           ssl->in_msg[3];
+    return MBEDTLS_GET_UINT24_BE(ssl->in_msg, 1);
 }
 
 int mbedtls_ssl_prepare_handshake_record(mbedtls_ssl_context *ssl)
@@ -3241,7 +3236,7 @@
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) {
         int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-        unsigned int recv_msg_seq = (ssl->in_msg[4] << 8) | ssl->in_msg[5];
+        unsigned int recv_msg_seq = MBEDTLS_GET_UINT16_BE(ssl->in_msg, 4);
 
         if (ssl_check_hs_header(ssl) != 0) {
             MBEDTLS_SSL_DEBUG_MSG(1, ("invalid handshake header"));
@@ -3594,7 +3589,7 @@
         return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
     }
 
-    *olen = p - obuf;
+    *olen = (size_t) (p - obuf);
 
     /* Go back and fill length fields */
     obuf[27] = (unsigned char) (*olen - 28);
@@ -3856,8 +3851,7 @@
      */
 
     rec->data_offset = rec_hdr_len_offset + rec_hdr_len_len;
-    rec->data_len    = ((size_t) buf[rec_hdr_len_offset + 0] << 8) |
-                       ((size_t) buf[rec_hdr_len_offset + 1] << 0);
+    rec->data_len    = MBEDTLS_GET_UINT16_BE(buf, rec_hdr_len_offset);
     MBEDTLS_SSL_DEBUG_BUF(4, "input record header", buf, rec->data_offset);
 
     MBEDTLS_SSL_DEBUG_MSG(3, ("input record: msgtype = %u, "
@@ -3885,7 +3879,7 @@
      */
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) {
-        rec_epoch = (rec->ctr[0] << 8) | rec->ctr[1];
+        rec_epoch = MBEDTLS_GET_UINT16_BE(rec->ctr, 0);
 
         /* Check that the datagram is large enough to contain a record
          * of the advertised length. */
@@ -3935,7 +3929,7 @@
 MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_check_client_reconnect(mbedtls_ssl_context *ssl)
 {
-    unsigned int rec_epoch = (ssl->in_ctr[0] << 8) | ssl->in_ctr[1];
+    unsigned int rec_epoch = MBEDTLS_GET_UINT16_BE(ssl->in_ctr, 0);
 
     /*
      * Check for an epoch 0 ClientHello. We can't use in_msg here to
@@ -4257,9 +4251,7 @@
     hs_buf = &hs->buffering.hs[0];
     if ((hs_buf->is_valid == 1) && (hs_buf->is_complete == 1)) {
         /* Synthesize a record containing the buffered HS message. */
-        size_t msg_len = (hs_buf->data[1] << 16) |
-                         (hs_buf->data[2] << 8) |
-                         hs_buf->data[3];
+        size_t msg_len = MBEDTLS_GET_UINT24_BE(hs_buf->data, 1);
 
         /* Double-check that we haven't accidentally buffered
          * a message that doesn't fit into the input buffer. */
@@ -4356,7 +4348,7 @@
         case MBEDTLS_SSL_MSG_HANDSHAKE:
         {
             unsigned recv_msg_seq_offset;
-            unsigned recv_msg_seq = (ssl->in_msg[4] << 8) | ssl->in_msg[5];
+            unsigned recv_msg_seq = MBEDTLS_GET_UINT16_BE(ssl->in_msg, 4);
             mbedtls_ssl_hs_buffer *hs_buf;
             size_t msg_len = ssl->in_hslen - 12;
 
diff --git a/library/ssl_ticket.c b/library/ssl_ticket.c
index 61c87be..8e7c145 100644
--- a/library/ssl_ticket.c
+++ b/library/ssl_ticket.c
@@ -341,7 +341,7 @@
 
     /* Dump session state */
     if ((ret = mbedtls_ssl_session_save(session,
-                                        state, end - state,
+                                        state, (size_t) (end - state),
                                         &clear_len)) != 0 ||
         (unsigned long) clear_len > 65535) {
         goto cleanup;
@@ -364,7 +364,7 @@
                                                /* Additional data: key name, IV and length */
                                                key_name, TICKET_ADD_DATA_LEN,
                                                state, clear_len,
-                                               state, end - state, &ciph_len,
+                                               state, (size_t) (end - state), &ciph_len,
                                                TICKET_AUTH_TAG_BYTES)) != 0) {
         goto cleanup;
     }
@@ -444,7 +444,7 @@
         goto cleanup;
     }
 
-    enc_len = (enc_len_p[0] << 8) | enc_len_p[1];
+    enc_len = MBEDTLS_GET_UINT16_BE(enc_len_p, 0);
 
     if (len != TICKET_MIN_LEN + enc_len) {
         ret = MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index b163e93..6678b71 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3808,7 +3808,7 @@
     session->tls_version = (mbedtls_ssl_protocol_version) (0x0300 | *p++);
 
     /* Dispatch according to TLS version. */
-    remaining_len = (end - p);
+    remaining_len = (size_t) (end - p);
     switch (session->tls_version) {
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
         case MBEDTLS_SSL_VERSION_TLS1_2:
@@ -4519,7 +4519,7 @@
     }
 
 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
-    used += 2 + ssl->transform->in_cid_len + ssl->transform->out_cid_len;
+    used += 2U + ssl->transform->in_cid_len + ssl->transform->out_cid_len;
     if (used <= buf_len) {
         *p++ = ssl->transform->in_cid_len;
         memcpy(p, ssl->transform->in_cid, ssl->transform->in_cid_len);
@@ -4800,7 +4800,7 @@
         return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
     }
 
-    ssl->mtu = (p[0] << 8) | p[1];
+    ssl->mtu = MBEDTLS_GET_UINT16_BE(p, 0);
     p += 2;
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
@@ -5745,7 +5745,7 @@
                                  uint32_t *flags)
 {
     int ret = 0;
-    int usage = 0;
+    unsigned int usage = 0;
     const char *ext_oid;
     size_t ext_len;
 
@@ -6848,7 +6848,7 @@
 
         /* Write length only when we know the actual value */
         if ((ret = mbedtls_dhm_calc_secret(&ssl->handshake->dhm_ctx,
-                                           p + 2, end - (p + 2), &len,
+                                           p + 2, (size_t) (end - (p + 2)), &len,
                                            ssl->conf->f_rng, ssl->conf->p_rng)) != 0) {
             MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_dhm_calc_secret", ret);
             return ret;
@@ -6865,7 +6865,7 @@
         size_t zlen;
 
         if ((ret = mbedtls_ecdh_calc_secret(&ssl->handshake->ecdh_ctx, &zlen,
-                                            p + 2, end - (p + 2),
+                                            p + 2, (size_t) (end - (p + 2)),
                                             ssl->conf->f_rng, ssl->conf->p_rng)) != 0) {
             MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecdh_calc_secret", ret);
             return ret;
@@ -6898,7 +6898,7 @@
     memcpy(p, psk, psk_len);
     p += psk_len;
 
-    ssl->handshake->pmslen = p - ssl->handshake->premaster;
+    ssl->handshake->pmslen = (size_t) (p - ssl->handshake->premaster);
 
     return 0;
 }
@@ -7156,7 +7156,7 @@
     /*
      * Same message structure as in mbedtls_ssl_write_certificate()
      */
-    n = (ssl->in_msg[i+1] << 8) | ssl->in_msg[i+2];
+    n = MBEDTLS_GET_UINT16_BE(ssl->in_msg, i + 1);
 
     if (ssl->in_msg[i] != 0 ||
         ssl->in_hslen != n + 3 + mbedtls_ssl_hs_hdr_len(ssl)) {
@@ -7190,8 +7190,7 @@
         }
 
         /* Read length of the next CRT in the chain. */
-        n = ((unsigned int) ssl->in_msg[i + 1] << 8)
-            | (unsigned int) ssl->in_msg[i + 2];
+        n = MBEDTLS_GET_UINT16_BE(ssl->in_msg, i + 1);
         i += 3;
 
         if (n < 128 || i + n > ssl->in_hslen) {
@@ -7719,7 +7718,7 @@
                                          unsigned char *padbuf, size_t hlen,
                                          unsigned char *buf, int from)
 {
-    int len = 12;
+    unsigned int len = 12;
     const char *sender;
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
     psa_status_t status;
@@ -7919,7 +7918,8 @@
 
 int mbedtls_ssl_write_finished(mbedtls_ssl_context *ssl)
 {
-    int ret, hash_len;
+    int ret;
+    unsigned int hash_len;
 
     MBEDTLS_SSL_DEBUG_MSG(2, ("=> write finished"));
 
@@ -9091,7 +9091,7 @@
         return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
     }
 
-    session->ciphersuite = (p[0] << 8) | p[1];
+    session->ciphersuite = MBEDTLS_GET_UINT16_BE(p, 0);
     p += 2;
 
     session->id_len = *p++;
@@ -9127,7 +9127,7 @@
         return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
     }
 
-    cert_len = (p[0] << 16) | (p[1] << 8) | p[2];
+    cert_len = MBEDTLS_GET_UINT24_BE(p, 0);
     p += 3;
 
     if (cert_len != 0) {
@@ -9199,7 +9199,7 @@
         return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
     }
 
-    session->ticket_len = (p[0] << 16) | (p[1] << 8) | p[2];
+    session->ticket_len = MBEDTLS_GET_UINT24_BE(p, 0);
     p += 3;
 
     if (session->ticket_len != 0) {
@@ -9381,7 +9381,7 @@
     }
 
     /* Length of supported_signature_algorithms */
-    supported_sig_alg_len = p - supported_sig_alg;
+    supported_sig_alg_len = (size_t) (p - supported_sig_alg);
     if (supported_sig_alg_len == 0) {
         MBEDTLS_SSL_DEBUG_MSG(1, ("No signature algorithms defined."));
         return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
@@ -9391,7 +9391,7 @@
     MBEDTLS_PUT_UINT16_BE(supported_sig_alg_len + 2, buf, 2);
     MBEDTLS_PUT_UINT16_BE(supported_sig_alg_len, buf, 4);
 
-    *out_len = p - buf;
+    *out_len = (size_t) (p - buf);
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_3)
     mbedtls_ssl_tls13_set_hs_sent_ext_mask(ssl, MBEDTLS_TLS_EXT_SIG_ALG);
diff --git a/library/ssl_tls12_client.c b/library/ssl_tls12_client.c
index 9aa46bd..08549a8 100644
--- a/library/ssl_tls12_client.c
+++ b/library/ssl_tls12_client.c
@@ -607,7 +607,7 @@
     p += ext_len;
 #endif
 
-    *out_len = p - buf;
+    *out_len = (size_t) (p - buf);
 
     return 0;
 }
@@ -941,7 +941,7 @@
         return MBEDTLS_ERR_SSL_DECODE_ERROR;
     }
 
-    list_len = (buf[0] << 8) | buf[1];
+    list_len = MBEDTLS_GET_UINT16_BE(buf, 0);
     if (list_len != len - 2) {
         mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
@@ -1304,8 +1304,7 @@
     }
 
     if (ssl->in_hslen > mbedtls_ssl_hs_hdr_len(ssl) + 39 + n) {
-        ext_len = ((buf[38 + n] <<  8)
-                   | (buf[39 + n]));
+        ext_len = MBEDTLS_GET_UINT16_BE(buf, 38 + n);
 
         if ((ext_len > 0 && ext_len < 4) ||
             ssl->in_hslen != mbedtls_ssl_hs_hdr_len(ssl) + 40 + n + ext_len) {
@@ -1326,7 +1325,7 @@
     }
 
     /* ciphersuite (used later) */
-    i = (buf[35 + n] << 8) | buf[36 + n];
+    i = (int) MBEDTLS_GET_UINT16_BE(buf, n + 35);
 
     /*
      * Read and check compression
@@ -1447,10 +1446,8 @@
                            ext_len));
 
     while (ext_len) {
-        unsigned int ext_id   = ((ext[0] <<  8)
-                                 | (ext[1]));
-        unsigned int ext_size = ((ext[2] <<  8)
-                                 | (ext[3]));
+        unsigned int ext_id   = MBEDTLS_GET_UINT16_BE(ext, 0);
+        unsigned int ext_size = MBEDTLS_GET_UINT16_BE(ext, 2);
 
         if (ext_size + 4 > ext_len) {
             MBEDTLS_SSL_DEBUG_MSG(1, ("bad server hello message"));
@@ -1741,9 +1738,8 @@
     }
 
     /* Next two bytes are the namedcurve value */
-    tls_id = *(*p)++;
-    tls_id <<= 8;
-    tls_id |= *(*p)++;
+    tls_id = MBEDTLS_GET_UINT16_BE(*p, 0);
+    *p += 2;
 
     /* Check it's a curve we offered */
     if (mbedtls_ssl_check_curve_tls_id(ssl, tls_id) != 0) {
@@ -1883,7 +1879,7 @@
                               ("bad server key exchange message (psk_identity_hint length)"));
         return MBEDTLS_ERR_SSL_DECODE_ERROR;
     }
-    len = (*p)[0] << 8 | (*p)[1];
+    len = MBEDTLS_GET_UINT16_BE(*p, 0);
     *p += 2;
 
     if (end - (*p) < len) {
@@ -2174,7 +2170,7 @@
 #endif
     p   = ssl->in_msg + mbedtls_ssl_hs_hdr_len(ssl);
     end = ssl->in_msg + ssl->in_hslen;
-    MBEDTLS_SSL_DEBUG_BUF(3,   "server key exchange", p, end - p);
+    MBEDTLS_SSL_DEBUG_BUF(3,   "server key exchange", p, (size_t) (end - p));
 
 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
     if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
@@ -2299,7 +2295,7 @@
         mbedtls_md_type_t md_alg = MBEDTLS_MD_NONE;
         mbedtls_pk_type_t pk_alg = MBEDTLS_PK_NONE;
         unsigned char *params = ssl->in_msg + mbedtls_ssl_hs_hdr_len(ssl);
-        size_t params_len = p - params;
+        size_t params_len = (size_t) (p - params);
         void *rs_ctx = NULL;
         uint16_t sig_alg;
 
@@ -2357,7 +2353,7 @@
                 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
             return MBEDTLS_ERR_SSL_DECODE_ERROR;
         }
-        sig_len = (p[0] << 8) | p[1];
+        sig_len = MBEDTLS_GET_UINT16_BE(p, 0);
         p += 2;
 
         if (p != end - sig_len) {
@@ -2585,8 +2581,7 @@
     }
 
     /* supported_signature_algorithms */
-    sig_alg_len = ((buf[mbedtls_ssl_hs_hdr_len(ssl) + 1 + n] <<  8)
-                   | (buf[mbedtls_ssl_hs_hdr_len(ssl) + 2 + n]));
+    sig_alg_len = MBEDTLS_GET_UINT16_BE(buf, mbedtls_ssl_hs_hdr_len(ssl) + 1 + n);
 
     /*
      * The furthest access in buf is in the loop few lines below:
@@ -2621,8 +2616,7 @@
     n += 2 + sig_alg_len;
 
     /* certificate_authorities */
-    dn_len = ((buf[mbedtls_ssl_hs_hdr_len(ssl) + 1 + n] <<  8)
-              | (buf[mbedtls_ssl_hs_hdr_len(ssl) + 2 + n]));
+    dn_len = MBEDTLS_GET_UINT16_BE(buf, mbedtls_ssl_hs_hdr_len(ssl) + 1 + n);
 
     n += dn_len;
     if (ssl->in_hslen != mbedtls_ssl_hs_hdr_len(ssl) + 3 + n) {
@@ -3252,9 +3246,9 @@
     size_t hashlen;
     void *rs_ctx = NULL;
 #if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
-    size_t out_buf_len = ssl->out_buf_len - (ssl->out_msg - ssl->out_buf);
+    size_t out_buf_len = ssl->out_buf_len - (size_t) (ssl->out_msg - ssl->out_buf);
 #else
-    size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN - (ssl->out_msg - ssl->out_buf);
+    size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN - (size_t) (ssl->out_msg - ssl->out_buf);
 #endif
 
     MBEDTLS_SSL_DEBUG_MSG(2, ("=> write certificate verify"));
@@ -3421,10 +3415,9 @@
 
     msg = ssl->in_msg + mbedtls_ssl_hs_hdr_len(ssl);
 
-    lifetime = (((uint32_t) msg[0]) << 24) | (msg[1] << 16) |
-               (msg[2] << 8) | (msg[3]);
+    lifetime = MBEDTLS_GET_UINT32_BE(msg, 0);
 
-    ticket_len = (msg[4] << 8) | (msg[5]);
+    ticket_len = MBEDTLS_GET_UINT16_BE(msg, 4);
 
     if (ticket_len + 6 + mbedtls_ssl_hs_hdr_len(ssl) != ssl->in_hslen) {
         MBEDTLS_SSL_DEBUG_MSG(1, ("bad new session ticket message"));
diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index b007e5c..a07d0fb 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -192,7 +192,7 @@
                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
         return MBEDTLS_ERR_SSL_DECODE_ERROR;
     }
-    list_size = ((buf[0] << 8) | (buf[1]));
+    list_size = MBEDTLS_GET_UINT16_BE(buf, 0);
     if (list_size + 2 != len ||
         list_size % 2 != 0) {
         MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
@@ -957,7 +957,7 @@
     }
 
     MBEDTLS_SSL_DEBUG_MSG(3, ("client hello, message len.: %d",
-                              (ssl->in_len[0] << 8) | ssl->in_len[1]));
+                              MBEDTLS_GET_UINT16_BE(ssl->in_len, 0)));
 
     MBEDTLS_SSL_DEBUG_MSG(3, ("client hello, protocol version: [%d:%d]",
                               buf[1], buf[2]));
@@ -993,7 +993,7 @@
     }
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
-    msg_len = (ssl->in_len[0] << 8) | ssl->in_len[1];
+    msg_len = MBEDTLS_GET_UINT16_BE(ssl->in_len, 0);
 
 #if defined(MBEDTLS_SSL_RENEGOTIATION)
     if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) {
@@ -1251,8 +1251,7 @@
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
     ciph_offset = 35 + sess_len;
 
-    ciph_len = (buf[ciph_offset + 0] << 8)
-               | (buf[ciph_offset + 1]);
+    ciph_len = MBEDTLS_GET_UINT16_BE(buf, ciph_offset);
 
     if (ciph_len < 2 ||
         ciph_len + 2 + ciph_offset + 1 > msg_len || /* 1 for comp. alg. len */
@@ -1300,8 +1299,7 @@
             return MBEDTLS_ERR_SSL_DECODE_ERROR;
         }
 
-        ext_len = (buf[ext_offset + 0] << 8)
-                  | (buf[ext_offset + 1]);
+        ext_len = MBEDTLS_GET_UINT16_BE(buf, ext_offset);
 
         if (msg_len != ext_offset + 2 + ext_len) {
             MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
@@ -1325,8 +1323,8 @@
                                            MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
             return MBEDTLS_ERR_SSL_DECODE_ERROR;
         }
-        ext_id   = ((ext[0] <<  8) | (ext[1]));
-        ext_size = ((ext[2] <<  8) | (ext[3]));
+        ext_id   = MBEDTLS_GET_UINT16_BE(ext, 0);
+        ext_size = MBEDTLS_GET_UINT16_BE(ext, 2);
 
         if (ext_size + 4 > ext_len) {
             MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
@@ -1858,7 +1856,7 @@
         *p++ = 0x00;
     }
 
-    *olen = p - buf;
+    *olen = (size_t) (p - buf);
 }
 
 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
@@ -1950,7 +1948,7 @@
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
     ret = mbedtls_psa_ecjpake_write_round(&ssl->handshake->psa_pake_ctx,
-                                          p + 2, end - p - 2, &kkpp_len,
+                                          p + 2, (size_t) (end - p - 2), &kkpp_len,
                                           MBEDTLS_ECJPAKE_ROUND_ONE);
     if (ret != 0) {
         psa_destroy_key(ssl->handshake->psa_pake_password);
@@ -1960,7 +1958,7 @@
     }
 #else
     ret = mbedtls_ecjpake_write_round_one(&ssl->handshake->ecjpake_ctx,
-                                          p + 2, end - p - 2, &kkpp_len,
+                                          p + 2, (size_t) (end - p - 2), &kkpp_len,
                                           ssl->conf->f_rng, ssl->conf->p_rng);
     if (ret != 0) {
         MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecjpake_write_round_one", ret);
@@ -2081,7 +2079,7 @@
 
     MBEDTLS_SSL_DEBUG_BUF(3, "cookie sent", cookie_len_byte + 1, *cookie_len_byte);
 
-    ssl->out_msglen  = p - ssl->out_msg;
+    ssl->out_msglen  = (size_t) (p - ssl->out_msg);
     ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
     ssl->out_msg[0]  = MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST;
 
@@ -2386,7 +2384,7 @@
         p += 2 + ext_len;
     }
 
-    ssl->out_msglen  = p - buf;
+    ssl->out_msglen  = (size_t) (p - buf);
     ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
     ssl->out_msg[0]  = MBEDTLS_SSL_HS_SERVER_HELLO;
 
@@ -2570,12 +2568,12 @@
 
             MBEDTLS_SSL_DEBUG_BUF(3, "requested DN", p - dn_size, dn_size);
 
-            total_dn_size += 2 + dn_size;
+            total_dn_size += (unsigned short) (2 + dn_size);
             crt = crt->next;
         }
     }
 
-    ssl->out_msglen  = p - buf;
+    ssl->out_msglen  = (size_t) (p - buf);
     ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
     ssl->out_msg[0]  = MBEDTLS_SSL_HS_CERTIFICATE_REQUEST;
     MBEDTLS_PUT_UINT16_BE(total_dn_size, ssl->out_msg, 4 + ct_len + sa_len);
@@ -2779,9 +2777,9 @@
 
 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
 #if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
-    size_t out_buf_len = ssl->out_buf_len - (ssl->out_msg - ssl->out_buf);
+    size_t out_buf_len = ssl->out_buf_len - (size_t) (ssl->out_msg - ssl->out_buf);
 #else
-    size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN - (ssl->out_msg - ssl->out_buf);
+    size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN - (size_t) (ssl->out_msg - ssl->out_buf);
 #endif
 #endif
 
@@ -3086,7 +3084,7 @@
             return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
         }
 
-        size_t dig_signed_len = ssl->out_msg + ssl->out_msglen - dig_signed;
+        size_t dig_signed_len = (size_t) (ssl->out_msg + ssl->out_msglen - dig_signed);
         size_t hashlen = 0;
         unsigned char hash[MBEDTLS_MD_MAX_SIZE];
 
@@ -3101,8 +3099,8 @@
         mbedtls_pk_type_t sig_alg =
             mbedtls_ssl_get_ciphersuite_sig_pk_alg(ciphersuite_info);
 
-        unsigned int sig_hash =
-            mbedtls_ssl_tls12_get_preferred_hash_for_sig_alg(
+        unsigned char sig_hash =
+            (unsigned char) mbedtls_ssl_tls12_get_preferred_hash_for_sig_alg(
                 ssl, mbedtls_ssl_sig_from_pk_alg(sig_alg));
 
         mbedtls_md_type_t md_alg = mbedtls_ssl_md_alg_from_hash(sig_hash);
@@ -3360,7 +3358,7 @@
         return MBEDTLS_ERR_SSL_DECODE_ERROR;
     }
 
-    n = ((*p)[0] << 8) | (*p)[1];
+    n = MBEDTLS_GET_UINT16_BE(*p, 0);
     *p += 2;
 
     if (*p + n > end) {
@@ -3593,7 +3591,7 @@
         return MBEDTLS_ERR_SSL_DECODE_ERROR;
     }
 
-    n = ((*p)[0] << 8) | (*p)[1];
+    n = MBEDTLS_GET_UINT16_BE(*p, 0);
     *p += 2;
 
     if (n == 0 || n > end - *p) {
@@ -3763,7 +3761,7 @@
         handshake->xxdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
 #else
         if ((ret = mbedtls_ecdh_read_public(&ssl->handshake->ecdh_ctx,
-                                            p, end - p)) != 0) {
+                                            p, (size_t) (end - p))) != 0) {
             MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecdh_read_public", ret);
             return MBEDTLS_ERR_SSL_DECODE_ERROR;
         }
@@ -3976,7 +3974,7 @@
         }
 
         if ((ret = mbedtls_ecdh_read_public(&ssl->handshake->ecdh_ctx,
-                                            p, end - p)) != 0) {
+                                            p, (size_t) (end - p))) != 0) {
             MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecdh_read_public", ret);
             return MBEDTLS_ERR_SSL_DECODE_ERROR;
         }
@@ -4005,7 +4003,7 @@
     if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE) {
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
         if ((ret = mbedtls_psa_ecjpake_read_round(
-                 &ssl->handshake->psa_pake_ctx, p, end - p,
+                 &ssl->handshake->psa_pake_ctx, p, (size_t) (end - p),
                  MBEDTLS_ECJPAKE_ROUND_TWO)) != 0) {
             psa_destroy_key(ssl->handshake->psa_pake_password);
             psa_pake_abort(&ssl->handshake->psa_pake_ctx);
@@ -4015,7 +4013,7 @@
         }
 #else
         ret = mbedtls_ecjpake_read_round_two(&ssl->handshake->ecjpake_ctx,
-                                             p, end - p);
+                                             p, (size_t) (end - p));
         if (ret != 0) {
             MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecjpake_read_round_two", ret);
             return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
@@ -4189,7 +4187,7 @@
         return MBEDTLS_ERR_SSL_DECODE_ERROR;
     }
 
-    sig_len = (ssl->in_msg[i] << 8) | ssl->in_msg[i+1];
+    sig_len = MBEDTLS_GET_UINT16_BE(ssl->in_msg, i);
     i += 2;
 
     if (i + sig_len != ssl->in_hslen) {
diff --git a/library/x509_create.c b/library/x509_create.c
index 424cce1..8f31c3b 100644
--- a/library/x509_create.c
+++ b/library/x509_create.c
@@ -169,7 +169,7 @@
             return MBEDTLS_ERR_X509_INVALID_NAME;
         }
     }
-    *data_len = d - data;
+    *data_len = (size_t) (d - data);
     return 0;
 }
 
@@ -297,8 +297,8 @@
 
     while (c <= end) {
         if (in_attr_type && *c == '=') {
-            if ((attr_descr = x509_attr_descr_from_name(s, c - s)) == NULL) {
-                if ((mbedtls_oid_from_numeric_string(&oid, s, c - s)) != 0) {
+            if ((attr_descr = x509_attr_descr_from_name(s, (size_t) (c - s))) == NULL) {
+                if ((mbedtls_oid_from_numeric_string(&oid, s, (size_t) (c - s))) != 0) {
                     return MBEDTLS_ERR_X509_INVALID_NAME;
                 } else {
                     numericoid = 1;
@@ -322,7 +322,7 @@
                 /* We know that c >= s (loop invariant) and c != s (in this
                  * else branch), hence c - s - 1 >= 0. */
                 parse_ret = parse_attribute_value_hex_der_encoded(
-                    s + 1, c - s - 1,
+                    s + 1, (size_t) (c - s) - 1,
                     data, sizeof(data), &data_len, &tag);
                 if (parse_ret != 0) {
                     mbedtls_free(oid.p);
diff --git a/library/x509_crl.c b/library/x509_crl.c
index cad784e..fdbad23 100644
--- a/library/x509_crl.c
+++ b/library/x509_crl.c
@@ -367,7 +367,7 @@
     }
 
     end = p + len;
-    crl->tbs.len = end - crl->tbs.p;
+    crl->tbs.len = (size_t) (end - crl->tbs.p);
 
     /*
      * Version  ::=  INTEGER  OPTIONAL {  v1(0), v2(1)  }
@@ -411,7 +411,7 @@
         return ret;
     }
 
-    crl->issuer_raw.len = p - crl->issuer_raw.p;
+    crl->issuer_raw.len = (size_t) (p - crl->issuer_raw.p);
 
     /*
      * thisUpdate          Time
diff --git a/library/x509_crt.c b/library/x509_crt.c
index f41eb47..1fe4448 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -1108,7 +1108,7 @@
     }
 
     end = crt_end = p + len;
-    crt->raw.len = crt_end - buf;
+    crt->raw.len = (size_t) (crt_end - buf);
     if (make_copy != 0) {
         /* Create and populate a new buffer for the raw field. */
         crt->raw.p = p = mbedtls_calloc(1, crt->raw.len);
@@ -1138,7 +1138,7 @@
     }
 
     end = p + len;
-    crt->tbs.len = end - crt->tbs.p;
+    crt->tbs.len = (size_t) (end - crt->tbs.p);
 
     /*
      * Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
@@ -1185,7 +1185,7 @@
         return ret;
     }
 
-    crt->issuer_raw.len = p - crt->issuer_raw.p;
+    crt->issuer_raw.len = (size_t) (p - crt->issuer_raw.p);
 
     /*
      * Validity ::= SEQUENCE {
@@ -1215,7 +1215,7 @@
         return ret;
     }
 
-    crt->subject_raw.len = p - crt->subject_raw.p;
+    crt->subject_raw.len = (size_t) (p - crt->subject_raw.p);
 
     /*
      * SubjectPublicKeyInfo
@@ -1225,7 +1225,7 @@
         mbedtls_x509_crt_free(crt);
         return ret;
     }
-    crt->pk_raw.len = p - crt->pk_raw.p;
+    crt->pk_raw.len = (size_t) (p - crt->pk_raw.p);
 
     /*
      *  issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL,
diff --git a/library/x509_csr.c b/library/x509_csr.c
index a293ec0..79b1589 100644
--- a/library/x509_csr.c
+++ b/library/x509_csr.c
@@ -328,7 +328,7 @@
     }
 
     end = p + len;
-    csr->cri.len = end - csr->cri.p;
+    csr->cri.len = (size_t) (end - csr->cri.p);
 
     /*
      *  Version  ::=  INTEGER {  v1(0) }
@@ -361,7 +361,7 @@
         return ret;
     }
 
-    csr->subject_raw.len = p - csr->subject_raw.p;
+    csr->subject_raw.len = (size_t) (p - csr->subject_raw.p);
 
     /*
      *  subjectPKInfo SubjectPublicKeyInfo
diff --git a/library/x509write_crt.c b/library/x509write_crt.c
index 4c019ee..44b6b17 100644
--- a/library/x509write_crt.c
+++ b/library/x509write_crt.c
@@ -481,7 +481,7 @@
      */
     MBEDTLS_ASN1_CHK_ADD(pub_len,
                          mbedtls_pk_write_pubkey_der(ctx->subject_key,
-                                                     buf, c - buf));
+                                                     buf, (size_t) (c - buf)));
     c -= pub_len;
     len += pub_len;
 
diff --git a/library/x509write_csr.c b/library/x509write_csr.c
index 4e39755..254da69 100644
--- a/library/x509write_csr.c
+++ b/library/x509write_csr.c
@@ -185,7 +185,7 @@
                              MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC));
 
     MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_pk_write_pubkey_der(ctx->key,
-                                                              buf, c - buf));
+                                                              buf, (size_t) (c - buf)));
     c -= pub_len;
     len += pub_len;
 
@@ -276,7 +276,7 @@
                              MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));
 
     /* Zero the unused bytes at the start of buf */
-    memset(buf, 0, c2 - buf);
+    memset(buf, 0, (size_t) (c2 - buf));
 
     return (int) len;
 }