diff --git a/library/lms.c b/library/lms.c
index 4b4f151..b58aeea 100644
--- a/library/lms.c
+++ b/library/lms.c
@@ -54,45 +54,33 @@
 #define mbedtls_free   free
 #endif
 
-#define MERKLE_TREE_NODE_AM (1 << (MBEDTLS_LMS_H_TREE_HEIGHT + 1))
-#define MERKLE_TREE_LEAF_AM (1 << MBEDTLS_LMS_H_TREE_HEIGHT)
-#define MERKLE_TREE_INTR_AM (1 << MBEDTLS_LMS_H_TREE_HEIGHT)
+#define MBEDTLS_LMS_SIG_Q_LEAF_ID_OFFSET    (0)
+#define MBEDTLS_LMS_SIG_OTS_SIG_OFFSET      (MBEDTLS_LMS_SIG_Q_LEAF_ID_OFFSET + MBEDTLS_LMOTS_Q_LEAF_ID_LEN)
+#define MBEDTLS_LMS_SIG_TYPE_OFFSET         (MBEDTLS_LMS_SIG_OTS_SIG_OFFSET   + MBEDTLS_LMOTS_SIG_LEN)
+#define MBEDTLS_LMS_SIG_PATH_OFFSET         (MBEDTLS_LMS_SIG_TYPE_OFFSET      + MBEDTLS_LMS_TYPE_LEN)
+
+#define MBEDTLS_LMS_PUBLIC_KEY_TYPE_OFFSET      (0)
+#define MBEDTLS_LMS_PUBLIC_KEY_OTSTYPE_OFFSET   (MBEDTLS_LMS_PUBLIC_KEY_TYPE_OFFSET     + MBEDTLS_LMS_TYPE_LEN)
+#define MBEDTLS_LMS_PUBLIC_KEY_I_KEY_ID_OFFSET  (MBEDTLS_LMS_PUBLIC_KEY_OTSTYPE_OFFSET  + MBEDTLS_LMOTS_TYPE_LEN)
+#define MBEDTLS_LMS_PUBLIC_KEY_ROOT_NODE_OFFSET (MBEDTLS_LMS_PUBLIC_KEY_I_KEY_ID_OFFSET + MBEDTLS_LMOTS_I_KEY_ID_LEN)
+
+
+#define MERKLE_TREE_NODE_AM (1u << (MBEDTLS_LMS_H_TREE_HEIGHT + 1u))
+#define MERKLE_TREE_LEAF_NODE_AM (1u << MBEDTLS_LMS_H_TREE_HEIGHT)
+#define MERKLE_TREE_INTERNAL_NODE_AM (1u << MBEDTLS_LMS_H_TREE_HEIGHT)
 
 #define D_CONST_LEN           (2)
+static const unsigned char D_LEAF_CONSTANT_BYTES[D_CONST_LEN] = {0x82, 0x82};
+static const unsigned char D_INTERNAL_CONSTANT_BYTES[D_CONST_LEN] = {0x83, 0x83};
 
-#define D_LEAF_CONSTANT     (0x8282)
-#define D_INTR_CONSTANT     (0x8383)
-
-static void val_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;
-    }
-}
-
-static unsigned int network_bytes_to_val(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;
-}
-
-static int create_merkle_leaf_node( const mbedtls_lms_context *ctx,
+static int create_merkle_leaf_node( const unsigned char I_key_identifier[MBEDTLS_LMOTS_I_KEY_ID_LEN],
                                     unsigned char pub_key[MBEDTLS_LMOTS_N_HASH_LEN],
                                     unsigned int r_node_idx,
-                                    unsigned char out[32] )
+                                    unsigned char out[MBEDTLS_LMS_M_NODE_BYTES] )
 {
     psa_hash_operation_t op;
     psa_status_t status;
     size_t output_hash_len;
-    unsigned char D_LEAF_bytes[D_CONST_LEN];
     unsigned char r_node_idx_bytes[4];
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
@@ -100,64 +88,49 @@
     status = psa_hash_setup( &op, PSA_ALG_SHA_256 );
     ret = mbedtls_lms_error_from_psa( status );
     if ( ret != 0 )
-    {
-        goto out;
-    }
+        goto exit;
 
-    status = psa_hash_update( &op, ctx->MBEDTLS_PRIVATE(I_key_identifier),
-                              MBEDTLS_LMOTS_I_KEY_ID_LEN );
+    status = psa_hash_update( &op, I_key_identifier, MBEDTLS_LMOTS_I_KEY_ID_LEN );
     ret = mbedtls_lms_error_from_psa( status );
     if( ret )
-    {
-        goto out;
-    }
+        goto exit;
 
-    val_to_network_bytes( r_node_idx, 4, r_node_idx_bytes );
+    unsigned_int_to_network_bytes( r_node_idx, 4, r_node_idx_bytes );
     status = psa_hash_update( &op, r_node_idx_bytes, 4 );
     ret = mbedtls_lms_error_from_psa( status );
     if( ret )
-    {
-        goto out;
-    }
+        goto exit;
 
-    val_to_network_bytes( D_LEAF_CONSTANT, D_CONST_LEN, D_LEAF_bytes );
-    status = psa_hash_update( &op, D_LEAF_bytes, D_CONST_LEN );
+    status = psa_hash_update( &op, D_LEAF_CONSTANT_BYTES, D_CONST_LEN );
     ret = mbedtls_lms_error_from_psa( status );
     if( ret )
-    {
-        goto out;
-    }
+        goto exit;
 
     status = psa_hash_update( &op, pub_key, MBEDTLS_LMOTS_N_HASH_LEN );
     ret = mbedtls_lms_error_from_psa( status );
     if( ret )
-    {
-        goto out;
-    }
+        goto exit;
 
-    status = psa_hash_finish( &op, out, 32, &output_hash_len);
+    status = psa_hash_finish( &op, out, MBEDTLS_LMS_M_NODE_BYTES, &output_hash_len);
     ret = mbedtls_lms_error_from_psa( status );
     if( ret )
-    {
-        goto out;
-    }
+        goto exit;
 
-out:
+exit:
     psa_hash_abort( &op );
 
     return( ret );
 }
 
-static int create_merkle_intr_node( const mbedtls_lms_context *ctx,
-                                    const unsigned char left_node[32],
-                                    const unsigned char rght_node[32],
-                                    unsigned int r_node_idx,
-                                    unsigned char out[32] )
+static int create_merkle_internal_node( const unsigned char I_key_identifier[MBEDTLS_LMOTS_I_KEY_ID_LEN],
+                                        const unsigned char left_node[MBEDTLS_LMS_M_NODE_BYTES],
+                                        const unsigned char right_node[MBEDTLS_LMS_M_NODE_BYTES],
+                                        unsigned int r_node_idx,
+                                        unsigned char out[MBEDTLS_LMS_M_NODE_BYTES] )
 {
     psa_hash_operation_t op;
     psa_status_t status;
     size_t output_hash_len;
-    unsigned char D_INTR_bytes[D_CONST_LEN];
     unsigned char r_node_idx_bytes[4];
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
@@ -165,75 +138,62 @@
     status = psa_hash_setup( &op, PSA_ALG_SHA_256 );
     ret = mbedtls_lms_error_from_psa( status );
     if ( ret != 0 )
-    {
-        goto out;
-    }
+        goto exit;
 
-    status = psa_hash_update( &op, ctx->MBEDTLS_PRIVATE(I_key_identifier),
-                              MBEDTLS_LMOTS_I_KEY_ID_LEN );
+    status = psa_hash_update( &op, I_key_identifier, MBEDTLS_LMOTS_I_KEY_ID_LEN );
     ret = mbedtls_lms_error_from_psa( status );
     if( ret )
-    {
-        goto out;
-    }
+        goto exit;
 
-    val_to_network_bytes( r_node_idx, 4, r_node_idx_bytes );
+    unsigned_int_to_network_bytes( r_node_idx, 4, r_node_idx_bytes );
     status = psa_hash_update( &op, r_node_idx_bytes, 4 );
     ret = mbedtls_lms_error_from_psa( status );
     if( ret )
-    {
-        goto out;
-    }
+        goto exit;
 
-    val_to_network_bytes( D_INTR_CONSTANT, D_CONST_LEN, D_INTR_bytes );
-    status = psa_hash_update( &op, D_INTR_bytes, D_CONST_LEN );
+    status = psa_hash_update( &op, D_INTERNAL_CONSTANT_BYTES, D_CONST_LEN );
     ret = mbedtls_lms_error_from_psa( status );
     if( ret )
-    {
-        goto out;
-    }
+        goto exit;
 
     status = psa_hash_update( &op, left_node, MBEDTLS_LMOTS_N_HASH_LEN );
     ret = mbedtls_lms_error_from_psa( status );
     if( ret )
-    {
-        goto out;
-    }
+        goto exit;
 
-    status = psa_hash_update( &op, rght_node, MBEDTLS_LMOTS_N_HASH_LEN );
+    status = psa_hash_update( &op, right_node, MBEDTLS_LMOTS_N_HASH_LEN );
     ret = mbedtls_lms_error_from_psa( status );
     if( ret )
-    {
-        goto out;
-    }
+        goto exit;
 
-    ret = psa_hash_finish( &op, out, 32, &output_hash_len);
+    ret = psa_hash_finish( &op, out, MBEDTLS_LMS_M_NODE_BYTES, &output_hash_len);
     ret = mbedtls_lms_error_from_psa( status );
     if( ret )
-    {
-        goto out;
-    }
+        goto exit;
 
-out:
+exit:
     psa_hash_abort( &op );
 
     return ret;
 }
 
-static int generate_merkle_tree( mbedtls_lms_context *ctx,
-                                 unsigned char tree[MERKLE_TREE_NODE_AM][32] )
+static int calculate_merkle_tree( mbedtls_lms_private_t *ctx,
+                                 unsigned char tree[MERKLE_TREE_NODE_AM][MBEDTLS_LMS_M_NODE_BYTES] )
 {
     unsigned int priv_key_idx;
     unsigned int r_node_idx;
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
     /* First create the leaf nodes, in ascending order */
-    for( priv_key_idx = 0; priv_key_idx < MERKLE_TREE_INTR_AM; priv_key_idx++ )
+    for( priv_key_idx = 0; priv_key_idx < MERKLE_TREE_INTERNAL_NODE_AM;
+         priv_key_idx++ )
     {
-        r_node_idx = MERKLE_TREE_INTR_AM + priv_key_idx;
+        r_node_idx = MERKLE_TREE_INTERNAL_NODE_AM + priv_key_idx;
 
-        ret = create_merkle_leaf_node( ctx, ctx->MBEDTLS_PRIVATE(priv_keys)[priv_key_idx].pub_key,
-                                       r_node_idx, tree[r_node_idx] );
+        ret = create_merkle_leaf_node(
+            ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(I_key_identifier),
+            ctx->MBEDTLS_PRIVATE(ots_public_keys)[priv_key_idx].MBEDTLS_PRIVATE(public_key),
+            r_node_idx, tree[r_node_idx] );
         if( ret )
         {
             return( ret );
@@ -242,11 +202,12 @@
 
     /* Then the internal nodes, in reverse order so that we can guarantee the
      * parent has been created */
-    for( r_node_idx = MERKLE_TREE_INTR_AM - 1; r_node_idx > 0; r_node_idx-- )
+    for( r_node_idx = MERKLE_TREE_INTERNAL_NODE_AM - 1; r_node_idx > 0;
+         r_node_idx-- )
     {
-        ret = create_merkle_intr_node( ctx, tree[(r_node_idx * 2)],
-                                       tree[(r_node_idx * 2 + 1)],
-                                       r_node_idx, tree[r_node_idx] );
+        ret = create_merkle_internal_node(
+            ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(I_key_identifier),
+            tree[(r_node_idx * 2)], tree[(r_node_idx * 2 + 1)], r_node_idx, tree[r_node_idx] );
         if( ret )
         {
             return( ret );
@@ -256,18 +217,17 @@
     return( 0 );
 }
 
-static int get_merkle_path( mbedtls_lms_context *ctx,
-                            unsigned int leaf_node_id, unsigned char path[MBEDTLS_LMS_H_TREE_HEIGHT][32] )
+static int get_merkle_path( mbedtls_lms_private_t *ctx,
+                            unsigned int leaf_node_id,
+                            unsigned char path[MBEDTLS_LMS_H_TREE_HEIGHT][MBEDTLS_LMS_M_NODE_BYTES] )
 {
-    unsigned char tree[MERKLE_TREE_NODE_AM][32];
+    unsigned char tree[MERKLE_TREE_NODE_AM][MBEDTLS_LMS_M_NODE_BYTES];
     unsigned int curr_node_id = leaf_node_id;
-    unsigned int parent_node_id;
-    unsigned char sibling_relative_id;
     unsigned int adjacent_node_id;
     unsigned int height;
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
-    ret = generate_merkle_tree( ctx, tree);
+    ret = calculate_merkle_tree( ctx, tree);
     if( ret )
     {
         return( ret );
@@ -275,195 +235,107 @@
 
     for( height = 0; height < MBEDTLS_LMS_H_TREE_HEIGHT; height++ )
     {
-        parent_node_id = ( curr_node_id / 2 );
-
-        /* 0 if the node is a left child, 1 if the node is a right child */
-        sibling_relative_id = curr_node_id & 1;
-
-        adjacent_node_id = ( parent_node_id * 2 ) + ( 1 - sibling_relative_id );
+        adjacent_node_id = curr_node_id ^ 1;
 
         memcpy( &path[height], &tree[adjacent_node_id], MBEDTLS_LMOTS_N_HASH_LEN );
 
-        curr_node_id = parent_node_id;
+        curr_node_id >>=1;
     }
 
     return( 0 );
 }
 
-void mbedtls_lms_init( mbedtls_lms_context *ctx )
+void mbedtls_lms_init_public( mbedtls_lms_public_t *ctx )
 {
-    if( ctx == NULL )
-    {
-        return;
-    }
-
-    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_lms_context ) ) ;
+    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_lms_public_t ) ) ;
 }
 
-void mbedtls_lms_free( mbedtls_lms_context *ctx )
+void mbedtls_lms_free_public( mbedtls_lms_public_t *ctx )
 {
-    unsigned int idx;
-
-    if( ctx == NULL )
-    {
-        return;
-    }
-
-    if( ctx->MBEDTLS_PRIVATE(have_privkey) )
-    {
-        for( idx = 0; idx < MERKLE_TREE_LEAF_AM; idx++ )
-        {
-            mbedtls_lmots_free( &ctx->MBEDTLS_PRIVATE(priv_keys)[idx] );
-        }
-
-        mbedtls_free( ctx->MBEDTLS_PRIVATE(priv_keys) );
-    }
-
-    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_lms_context ) );
+    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_lms_public_t ) );
 }
 
-int mbedtls_lms_set_algorithm_type( mbedtls_lms_context *ctx,
-                                    mbedtls_lms_algorithm_type_t type,
-                                    mbedtls_lmots_algorithm_type_t otstype )
+int mbedtls_lms_import_public_key( mbedtls_lms_public_t *ctx,
+                               const unsigned char *key, size_t key_size )
 {
-    if( ctx == NULL )
+    mbedtls_lms_algorithm_type_t type;
+    mbedtls_lmots_algorithm_type_t otstype;
+
+    if( key_size < MBEDTLS_LMS_PUBLIC_KEY_LEN )
+    {
+        return( MBEDTLS_ERR_LMS_BUFFER_TOO_SMALL );
+    }
+
+    type = network_bytes_to_unsigned_int( MBEDTLS_LMS_TYPE_LEN, key + MBEDTLS_LMS_PUBLIC_KEY_TYPE_OFFSET );
+    if( type != MBEDTLS_LMS_SHA256_M32_H10 )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
+    ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(type) = type;
 
-    ctx->MBEDTLS_PRIVATE(type) = type;
-    ctx->MBEDTLS_PRIVATE(otstype) = otstype;
+    otstype = network_bytes_to_unsigned_int( MBEDTLS_LMOTS_TYPE_LEN,
+                                    key + MBEDTLS_LMS_PUBLIC_KEY_OTSTYPE_OFFSET );
+    if( otstype != MBEDTLS_LMOTS_SHA256_N32_W8 )
+    {
+        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
+    }
+    ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(otstype) = otstype;
+
+    memcpy( ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(I_key_identifier),
+            key + MBEDTLS_LMS_PUBLIC_KEY_I_KEY_ID_OFFSET,
+            MBEDTLS_LMOTS_I_KEY_ID_LEN );
+    memcpy( ctx->MBEDTLS_PRIVATE(T_1_pub_key), key + MBEDTLS_LMS_PUBLIC_KEY_ROOT_NODE_OFFSET,
+            MBEDTLS_LMOTS_N_HASH_LEN );
+
+    ctx->MBEDTLS_PRIVATE(have_public_key) = 1;
 
     return( 0 );
 }
 
-int mbedtls_lms_sign( mbedtls_lms_context *ctx,
-                      int ( *f_rng)(void *, unsigned char *, size_t),
-                      void* p_rng, unsigned char *msg, unsigned int msg_len,
-                      unsigned char *sig )
-{
-    unsigned int q_leaf_identifier;
-    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-
-    if( ctx == NULL )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
-
-    if( ! ctx->MBEDTLS_PRIVATE(have_privkey) )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
-
-    if( msg == NULL )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
-
-    if( sig == NULL )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
-
-
-    if( ctx->MBEDTLS_PRIVATE(type) != MBEDTLS_LMS_SHA256_M32_H10 )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
-
-    if( ctx->MBEDTLS_PRIVATE(otstype) != MBEDTLS_LMOTS_SHA256_N32_W8 )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
-
-
-    if( ctx->MBEDTLS_PRIVATE(q_next_usable_key) >= MERKLE_TREE_LEAF_AM )
-    {
-        return( MBEDTLS_ERR_LMS_OUT_OF_PRIV_KEYS );
-    }
-
-
-    q_leaf_identifier = ctx->MBEDTLS_PRIVATE(q_next_usable_key);
-    /* This new value must _always_ be written back to the disk before the
-     * signature is returned.
-     */
-    ctx->MBEDTLS_PRIVATE(q_next_usable_key) += 1;
-
-    ret = mbedtls_lmots_sign( &ctx->MBEDTLS_PRIVATE(priv_keys)[q_leaf_identifier],
-                              f_rng, p_rng, msg, msg_len,
-                              sig + MBEDTLS_LMS_SIG_OTS_SIG_OFFSET );
-    if( ret )
-    {
-        return( ret );
-    }
-
-    val_to_network_bytes( ctx->MBEDTLS_PRIVATE(type), MBEDTLS_LMS_TYPE_LEN,
-                          sig + MBEDTLS_LMS_SIG_TYPE_OFFSET );
-    val_to_network_bytes( q_leaf_identifier, MBEDTLS_LMOTS_Q_LEAF_ID_LEN,
-                          sig + MBEDTLS_LMS_SIG_Q_LEAF_ID_OFFSET);
-
-    ret = get_merkle_path( ctx, MERKLE_TREE_INTR_AM + q_leaf_identifier,
-                           ( unsigned char( * )[32] )( sig + MBEDTLS_LMS_SIG_PATH_OFFSET ) );
-    if( ret )
-    {
-        return( ret );
-    }
-
-    return( 0 );
-}
-
-int mbedtls_lms_verify( const mbedtls_lms_context *ctx,
-                        const unsigned char *msg, unsigned int msg_len,
-                        const unsigned char *sig )
+int mbedtls_lms_verify( const mbedtls_lms_public_t *ctx,
+                        const unsigned char *msg, size_t msg_size,
+                        const unsigned char *sig, size_t sig_size )
 {
     unsigned int q_leaf_identifier;
     unsigned char Kc_candidate_ots_pub_key[MBEDTLS_LMOTS_N_HASH_LEN];
-    unsigned char Tc_candidate_root_node[32];
+    unsigned char Tc_candidate_root_node[MBEDTLS_LMS_M_NODE_BYTES];
     unsigned int height;
     unsigned int curr_node_id;
     unsigned int parent_node_id;
     const unsigned char* left_node;
-    const unsigned char* rght_node;
+    const unsigned char* right_node;
+    mbedtls_lmots_parameters_t ots_params;
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
-    if( ctx == NULL )
+    if( ! ctx->MBEDTLS_PRIVATE(have_public_key) )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
 
-    if( ! ctx->MBEDTLS_PRIVATE(have_pubkey) )
+    if( sig_size != MBEDTLS_LMS_SIG_LEN )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
 
-    if( msg == NULL)
+    if( ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(type)
+        != MBEDTLS_LMS_SHA256_M32_H10 )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
 
-    if( sig == NULL)
+    if( ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(otstype)
+        != MBEDTLS_LMOTS_SHA256_N32_W8 )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
 
-    if( ctx->MBEDTLS_PRIVATE(type) != MBEDTLS_LMS_SHA256_M32_H10 )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
-
-    if( ctx->MBEDTLS_PRIVATE(otstype) != MBEDTLS_LMOTS_SHA256_N32_W8 )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
-
-
-    if( network_bytes_to_val( MBEDTLS_LMS_TYPE_LEN,
+    if( network_bytes_to_unsigned_int( MBEDTLS_LMS_TYPE_LEN,
                               sig + MBEDTLS_LMS_SIG_TYPE_OFFSET) != MBEDTLS_LMS_SHA256_M32_H10 )
     {
         return( MBEDTLS_ERR_LMS_VERIFY_FAILED );
     }
 
-    if( network_bytes_to_val( MBEDTLS_LMOTS_TYPE_LEN,
+    if( network_bytes_to_unsigned_int( MBEDTLS_LMOTS_TYPE_LEN,
                               sig + MBEDTLS_LMS_SIG_OTS_SIG_OFFSET + MBEDTLS_LMOTS_SIG_TYPE_OFFSET)
         != MBEDTLS_LMOTS_SHA256_N32_W8 )
     {
@@ -471,29 +343,39 @@
     }
 
 
-    q_leaf_identifier = network_bytes_to_val( MBEDTLS_LMOTS_Q_LEAF_ID_LEN,
+    q_leaf_identifier = network_bytes_to_unsigned_int( MBEDTLS_LMOTS_Q_LEAF_ID_LEN,
                                               sig + MBEDTLS_LMS_SIG_Q_LEAF_ID_OFFSET );
 
-    if( q_leaf_identifier >= MERKLE_TREE_LEAF_AM )
+    if( q_leaf_identifier >= MERKLE_TREE_LEAF_NODE_AM )
     {
         return( MBEDTLS_ERR_LMS_VERIFY_FAILED );
     }
 
-    ret = mbedtls_lmots_generate_pub_key_candidate( ctx->MBEDTLS_PRIVATE(I_key_identifier),
-                                                    sig + MBEDTLS_LMS_SIG_Q_LEAF_ID_OFFSET,
-                                                    msg, msg_len,
-                                                    sig + MBEDTLS_LMS_SIG_OTS_SIG_OFFSET,
-                                                    Kc_candidate_ots_pub_key );
+    memcpy(ots_params.MBEDTLS_PRIVATE(I_key_identifier),
+           ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(I_key_identifier),
+           MBEDTLS_LMOTS_I_KEY_ID_LEN);
+    unsigned_int_to_network_bytes( q_leaf_identifier,
+                                   MBEDTLS_LMOTS_Q_LEAF_ID_LEN,
+                                   ots_params.MBEDTLS_PRIVATE(q_leaf_identifier) );
+    ots_params.type = ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(otstype);
+
+    ret = mbedtls_lmots_calculate_public_key_candidate( &ots_params, msg, msg_size,
+                                                        sig + MBEDTLS_LMS_SIG_OTS_SIG_OFFSET,
+                                                        MBEDTLS_LMOTS_SIG_LEN,
+                                                        Kc_candidate_ots_pub_key,
+                                                        sizeof(Kc_candidate_ots_pub_key),
+                                                        NULL );
     if( ret )
     {
         return( ret );
     }
 
-    create_merkle_leaf_node( ctx, Kc_candidate_ots_pub_key,
-                             MERKLE_TREE_INTR_AM + q_leaf_identifier,
-                             Tc_candidate_root_node );
+    create_merkle_leaf_node(
+            ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(I_key_identifier),
+            Kc_candidate_ots_pub_key, MERKLE_TREE_INTERNAL_NODE_AM + q_leaf_identifier,
+            Tc_candidate_root_node );
 
-    curr_node_id = MERKLE_TREE_INTR_AM + q_leaf_identifier;
+    curr_node_id = MERKLE_TREE_INTERNAL_NODE_AM + q_leaf_identifier;
 
     for( height = 0; height < MBEDTLS_LMS_H_TREE_HEIGHT; height++ )
     {
@@ -502,17 +384,18 @@
         /* Left/right node ordering matters for the hash */
         if( curr_node_id & 1 )
         {
-            left_node = ( ( const unsigned char( * )[32] )( sig + MBEDTLS_LMS_SIG_PATH_OFFSET ) )[height];
-            rght_node = Tc_candidate_root_node;
+            left_node = ( ( const unsigned char( * )[MBEDTLS_LMS_M_NODE_BYTES] )( sig + MBEDTLS_LMS_SIG_PATH_OFFSET ) )[height];
+            right_node = Tc_candidate_root_node;
         }
         else
         {
             left_node = Tc_candidate_root_node;
-            rght_node = ( ( const unsigned char( * )[32] )( sig + MBEDTLS_LMS_SIG_PATH_OFFSET ) )[height];
+            right_node = ( ( const unsigned char( * )[MBEDTLS_LMS_M_NODE_BYTES] )( sig + MBEDTLS_LMS_SIG_PATH_OFFSET ) )[height];
         }
 
-        create_merkle_intr_node( ctx, left_node, rght_node, parent_node_id,
-                                 Tc_candidate_root_node);
+        create_merkle_internal_node(
+            ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(I_key_identifier),
+            left_node, right_node, parent_node_id, Tc_candidate_root_node);
 
         curr_node_id /= 2;
     }
@@ -526,115 +409,148 @@
     return( 0 );
 }
 
-int mbedtls_lms_import_pubkey( mbedtls_lms_context *ctx,
-                               const unsigned char *key )
+void mbedtls_lms_init_private( mbedtls_lms_private_t *ctx )
 {
-    mbedtls_lms_algorithm_type_t type;
-    mbedtls_lmots_algorithm_type_t otstype;
+    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_lms_public_t ) ) ;
+}
 
-    if( ctx == NULL )
+void mbedtls_lms_free_private( mbedtls_lms_private_t *ctx )
+{
+    unsigned int idx;
+
+    if( ctx->MBEDTLS_PRIVATE(have_private_key) )
     {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
+        for( idx = 0; idx < MERKLE_TREE_LEAF_NODE_AM; idx++ )
+        {
+            mbedtls_lmots_free_private( &ctx->MBEDTLS_PRIVATE(ots_private_keys)[idx] );
+            mbedtls_lmots_free_public( &ctx->MBEDTLS_PRIVATE(ots_public_keys)[idx] );
+        }
+
+        mbedtls_free( ctx->MBEDTLS_PRIVATE(ots_private_keys) );
+        mbedtls_free( ctx->MBEDTLS_PRIVATE(ots_public_keys) );
     }
 
-    if( key == NULL )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
+    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_lms_public_t ) );
+}
 
-    type = network_bytes_to_val( MBEDTLS_LMS_TYPE_LEN, key + MBEDTLS_LMS_PUBKEY_TYPE_OFFSET );
+
+int mbedtls_lms_generate_private_key( mbedtls_lms_private_t *ctx,
+                                      mbedtls_lms_algorithm_type_t type,
+                                      mbedtls_lmots_algorithm_type_t otstype,
+                                      int (*f_rng)(void *, unsigned char *, size_t),
+                                      void* p_rng, unsigned char *seed,
+                                      size_t seed_size )
+{
+    unsigned int idx = 0;
+    unsigned int free_idx = 0;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
     if( type != MBEDTLS_LMS_SHA256_M32_H10 )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
-    ctx->MBEDTLS_PRIVATE(type) = type;
 
-    otstype = network_bytes_to_val( MBEDTLS_LMOTS_TYPE_LEN,
-                                    key + MBEDTLS_LMS_PUBKEY_OTSTYPE_OFFSET );
     if( otstype != MBEDTLS_LMOTS_SHA256_N32_W8 )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
-    ctx->MBEDTLS_PRIVATE(otstype) = otstype;
 
-    memcpy( ctx->MBEDTLS_PRIVATE(I_key_identifier), key + MBEDTLS_LMS_PUBKEY_I_KEY_ID_OFFSET,
-            MBEDTLS_LMOTS_I_KEY_ID_LEN );
-    memcpy( ctx->MBEDTLS_PRIVATE(T_1_pub_key), key + MBEDTLS_LMS_PUBKEY_ROOT_NODE_OFFSET,
-            MBEDTLS_LMOTS_N_HASH_LEN );
+    if( ctx->MBEDTLS_PRIVATE(have_private_key) )
+    {
+        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
+    }
 
-    ctx->MBEDTLS_PRIVATE(have_pubkey) = 1;
+    ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(type) = type;
+    ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(otstype) = otstype;
+
+    f_rng( p_rng,
+           ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(I_key_identifier),
+           MBEDTLS_LMOTS_I_KEY_ID_LEN );
+
+    ctx->MBEDTLS_PRIVATE(ots_private_keys) = mbedtls_calloc( MERKLE_TREE_LEAF_NODE_AM,
+                                                             sizeof( mbedtls_lmots_private_t));
+    if( ctx->MBEDTLS_PRIVATE(ots_private_keys) == NULL )
+    {
+        ret = MBEDTLS_ERR_LMS_ALLOC_FAILED;
+        goto exit;
+    }
+
+    ctx->MBEDTLS_PRIVATE(ots_public_keys) = mbedtls_calloc( MERKLE_TREE_LEAF_NODE_AM,
+                                                            sizeof( mbedtls_lmots_public_t));
+    if( ctx->MBEDTLS_PRIVATE(ots_public_keys) == NULL )
+    {
+        ret = MBEDTLS_ERR_LMS_ALLOC_FAILED;
+        goto exit;
+    }
+
+    for( idx = 0; idx < MERKLE_TREE_LEAF_NODE_AM; idx++ )
+    {
+        mbedtls_lmots_init_private( &ctx->MBEDTLS_PRIVATE(ots_private_keys)[idx] );
+        mbedtls_lmots_init_public( &ctx->MBEDTLS_PRIVATE(ots_public_keys)[idx] );
+    }
+
+
+    for( idx = 0; idx < MERKLE_TREE_LEAF_NODE_AM; idx++ )
+    {
+        ret = mbedtls_lmots_generate_private_key( &ctx->MBEDTLS_PRIVATE(ots_private_keys)[idx],
+                                                  otstype,
+                                                  ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(I_key_identifier),
+                                                  idx, seed, seed_size );
+        if( ret)
+            goto exit;
+
+        ret = mbedtls_lmots_calculate_public_key( &ctx->MBEDTLS_PRIVATE(ots_public_keys)[idx],
+                                                  &ctx->MBEDTLS_PRIVATE(ots_private_keys)[idx] );
+        if( ret)
+            goto exit;
+    }
+
+    ctx->MBEDTLS_PRIVATE(q_next_usable_key) = 0;
+    ctx->MBEDTLS_PRIVATE(have_private_key) = 1;
+
+exit:
+    if( ret )
+    {
+        for ( free_idx = 0; free_idx < idx; free_idx++ ) {
+            mbedtls_lmots_free_private( &ctx->MBEDTLS_PRIVATE(ots_private_keys)[free_idx] );
+            mbedtls_lmots_free_public( &ctx->MBEDTLS_PRIVATE(ots_public_keys)[free_idx] );
+        }
+
+        mbedtls_free( ctx->MBEDTLS_PRIVATE(ots_private_keys) );
+        mbedtls_free( ctx->MBEDTLS_PRIVATE(ots_public_keys) );
+        return( ret );
+    }
 
     return( 0 );
 }
 
-int mbedtls_lms_export_pubkey( mbedtls_lms_context *ctx,
-                               unsigned char *key )
+int mbedtls_lms_calculate_public_key( mbedtls_lms_public_t *ctx,
+                                      mbedtls_lms_private_t *priv_ctx )
 {
-    if( ctx == NULL )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
-
-    if( key == NULL )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
-
-    if( ! ctx->MBEDTLS_PRIVATE(have_pubkey) )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
-
-    val_to_network_bytes( ctx->MBEDTLS_PRIVATE(type),
-                          MBEDTLS_LMS_TYPE_LEN, key + MBEDTLS_LMS_PUBKEY_TYPE_OFFSET );
-    val_to_network_bytes( ctx->MBEDTLS_PRIVATE(otstype),
-                          MBEDTLS_LMOTS_TYPE_LEN, key + MBEDTLS_LMS_PUBKEY_OTSTYPE_OFFSET );
-    memcpy( key + MBEDTLS_LMS_PUBKEY_I_KEY_ID_OFFSET,
-            ctx->MBEDTLS_PRIVATE(I_key_identifier),
-            MBEDTLS_LMOTS_I_KEY_ID_LEN );
-    memcpy( key + MBEDTLS_LMS_PUBKEY_ROOT_NODE_OFFSET,
-            ctx->MBEDTLS_PRIVATE(T_1_pub_key),
-            MBEDTLS_LMOTS_N_HASH_LEN );
-
-    return( 0 );
-}
-
-int mbedtls_lms_gen_pubkey( mbedtls_lms_context *ctx )
-{
-    unsigned char tree[MERKLE_TREE_NODE_AM][32];
-    unsigned int idx;
+    unsigned char tree[MERKLE_TREE_NODE_AM][MBEDTLS_LMS_M_NODE_BYTES];
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
-    if( ctx == NULL )
+    if( ! priv_ctx->MBEDTLS_PRIVATE( have_private_key ) )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
 
-    if( ! ctx->MBEDTLS_PRIVATE( have_privkey ) )
+    if( priv_ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(type)
+        != MBEDTLS_LMS_SHA256_M32_H10 )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
 
-    if( ctx->MBEDTLS_PRIVATE(type) != MBEDTLS_LMS_SHA256_M32_H10 )
+    if( priv_ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(otstype)
+        != MBEDTLS_LMOTS_SHA256_N32_W8 )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
 
-    if( ctx->MBEDTLS_PRIVATE(otstype) != MBEDTLS_LMOTS_SHA256_N32_W8 )
-    {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
+    memcpy( &ctx->MBEDTLS_PRIVATE(params), &priv_ctx->MBEDTLS_PRIVATE(params),
+            sizeof(mbedtls_lmots_parameters_t) );
 
-    for( idx = 0; idx < MERKLE_TREE_LEAF_AM; idx++ )
-    {
-        ret = mbedtls_lmots_gen_pubkey( &ctx->MBEDTLS_PRIVATE(priv_keys)[idx] );
-        if( ret )
-        {
-            return( ret );
-        }
-    }
-
-    ret = generate_merkle_tree( ctx, tree);
+    ret = calculate_merkle_tree( priv_ctx, tree);
     if( ret )
     {
         return( ret );
@@ -643,83 +559,112 @@
     /* Root node is always at position 1, due to 1-based indexing */
     memcpy( ctx->MBEDTLS_PRIVATE(T_1_pub_key), &tree[1], MBEDTLS_LMOTS_N_HASH_LEN );
 
-    ctx->MBEDTLS_PRIVATE(have_pubkey) = 1;
+    ctx->MBEDTLS_PRIVATE(have_public_key) = 1;
 
     return( 0 );
 }
 
-int mbedtls_lms_gen_privkey( mbedtls_lms_context *ctx,
-                             int ( *f_rng)(void *, unsigned char *, size_t),
-                             void* p_rng, unsigned char *seed,
-                             size_t seed_len )
+
+int mbedtls_lms_export_public_key( mbedtls_lms_public_t *ctx, unsigned char *key,
+                                   size_t key_size, size_t *key_len )
 {
-    unsigned int idx;
+    if( key_size < MBEDTLS_LMS_PUBLIC_KEY_LEN ) {
+        return( MBEDTLS_ERR_LMS_BUFFER_TOO_SMALL );
+    }
+
+    if( ! ctx->MBEDTLS_PRIVATE(have_public_key) )
+    {
+        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
+    }
+
+    unsigned_int_to_network_bytes(
+            ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(type),
+            MBEDTLS_LMS_TYPE_LEN, key + MBEDTLS_LMS_PUBLIC_KEY_TYPE_OFFSET );
+    unsigned_int_to_network_bytes(
+            ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(otstype),
+            MBEDTLS_LMOTS_TYPE_LEN, key + MBEDTLS_LMS_PUBLIC_KEY_OTSTYPE_OFFSET );
+    memcpy( key + MBEDTLS_LMS_PUBLIC_KEY_I_KEY_ID_OFFSET,
+            ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(I_key_identifier),
+            MBEDTLS_LMOTS_I_KEY_ID_LEN );
+    memcpy( key + MBEDTLS_LMS_PUBLIC_KEY_ROOT_NODE_OFFSET,
+            ctx->MBEDTLS_PRIVATE(T_1_pub_key),
+            MBEDTLS_LMOTS_N_HASH_LEN );
+
+    if( key_len != NULL ) {
+        *key_len = MBEDTLS_LMS_PUBLIC_KEY_LEN;
+    }
+
+    return( 0 );
+}
+
+
+int mbedtls_lms_sign( mbedtls_lms_private_t *ctx,
+                      int (*f_rng)(void *, unsigned char *, size_t),
+                      void* p_rng, unsigned char *msg, unsigned int msg_size,
+                      unsigned char *sig, size_t sig_size, size_t *sig_len)
+{
+    uint32_t q_leaf_identifier;
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
-    if( ctx == NULL )
+    if( ! ctx->MBEDTLS_PRIVATE(have_private_key) )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
 
-    if( ctx->MBEDTLS_PRIVATE(type) != MBEDTLS_LMS_SHA256_M32_H10 )
+    if( sig_size < MBEDTLS_LMS_SIG_LEN )
+    {
+        return( MBEDTLS_ERR_LMS_BUFFER_TOO_SMALL );
+    }
+
+    if( ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(type) != MBEDTLS_LMS_SHA256_M32_H10 )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
 
-    if( ctx->MBEDTLS_PRIVATE(otstype) != MBEDTLS_LMOTS_SHA256_N32_W8 )
+    if( ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(otstype)
+        != MBEDTLS_LMOTS_SHA256_N32_W8 )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }
 
-    if( ctx->MBEDTLS_PRIVATE(have_privkey) )
+    if( ctx->MBEDTLS_PRIVATE(q_next_usable_key) >= MERKLE_TREE_LEAF_NODE_AM )
     {
-        return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
-    }
-
-    f_rng( p_rng, ctx->MBEDTLS_PRIVATE(I_key_identifier),
-           sizeof( ctx->MBEDTLS_PRIVATE(I_key_identifier) ) );
-
-    ctx->MBEDTLS_PRIVATE(priv_keys) = mbedtls_calloc( MERKLE_TREE_LEAF_AM,
-                                                      sizeof( mbedtls_lmots_context));
-    if( ctx->MBEDTLS_PRIVATE(priv_keys) == NULL )
-    {
-        ret = MBEDTLS_ERR_LMS_ALLOC_FAILED;
-        goto out;
-    }
-
-    for( idx = 0; idx < MERKLE_TREE_LEAF_AM; idx++ )
-    {
-        mbedtls_lmots_init( &ctx->MBEDTLS_PRIVATE(priv_keys)[idx] );
-        ret = mbedtls_lmots_set_algorithm_type( &ctx->MBEDTLS_PRIVATE(priv_keys)[idx],
-                                                ctx->MBEDTLS_PRIVATE(otstype) );
-        if( ret)
-        {
-            goto out;
-        }
+        return( MBEDTLS_ERR_LMS_OUT_OF_PRIVATE_KEYS );
     }
 
 
-    for( idx = 0; idx < MERKLE_TREE_LEAF_AM; idx++ )
-    {
-        ret = mbedtls_lmots_gen_privkey( &ctx->MBEDTLS_PRIVATE(priv_keys)[idx],
-                                         ctx->MBEDTLS_PRIVATE(I_key_identifier),
-                                         idx, seed, seed_len );
-        if( ret)
-        {
-            goto out;
-        }
-    }
+    q_leaf_identifier = ctx->MBEDTLS_PRIVATE(q_next_usable_key);
+    /* This new value must _always_ be written back to the disk before the
+     * signature is returned.
+     */
+    ctx->MBEDTLS_PRIVATE(q_next_usable_key) += 1;
 
-    ctx->MBEDTLS_PRIVATE(q_next_usable_key) = 0;
-    ctx->MBEDTLS_PRIVATE(have_privkey) = 1;
-
-out:
+    ret = mbedtls_lmots_sign( &ctx->MBEDTLS_PRIVATE(ots_private_keys)[q_leaf_identifier],
+                              f_rng, p_rng, msg, msg_size,
+                              sig + MBEDTLS_LMS_SIG_OTS_SIG_OFFSET,
+                              MBEDTLS_LMS_SIG_LEN, NULL );
     if( ret )
     {
-        mbedtls_free( ctx->MBEDTLS_PRIVATE(priv_keys) );
         return( ret );
     }
 
+    unsigned_int_to_network_bytes( ctx->MBEDTLS_PRIVATE(params).MBEDTLS_PRIVATE(type),
+                                   MBEDTLS_LMS_TYPE_LEN, sig + MBEDTLS_LMS_SIG_TYPE_OFFSET );
+    unsigned_int_to_network_bytes( q_leaf_identifier, MBEDTLS_LMOTS_Q_LEAF_ID_LEN,
+                                   sig + MBEDTLS_LMS_SIG_Q_LEAF_ID_OFFSET);
+
+    ret = get_merkle_path( ctx, MERKLE_TREE_INTERNAL_NODE_AM + q_leaf_identifier,
+                           ( unsigned char( * )[MBEDTLS_LMS_M_NODE_BYTES] )( sig + MBEDTLS_LMS_SIG_PATH_OFFSET ) );
+    if( ret )
+    {
+        return( ret );
+    }
+
+    if( sig_len != NULL ) {
+        *sig_len = MBEDTLS_LMS_SIG_LEN;
+    }
+
+
     return( 0 );
 }