diff --git a/include/mbedtls/lms.h b/include/mbedtls/lms.h
new file mode 100644
index 0000000..868a667
--- /dev/null
+++ b/include/mbedtls/lms.h
@@ -0,0 +1,254 @@
+/**
+ * \file lms.h
+ *
+ * \brief This file provides an API for the LMS post-quantum-safe stateful-hash
+ *        public-key signature scheme.
+ */
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+#ifndef MBEDTLS_LMS_H
+#define MBEDTLS_LMS_H
+
+#include <stdint.h>
+#include <stddef.h>
+
+#include "mbedtls/private_access.h"
+#include "mbedtls/lmots.h"
+
+#define MBEDTLS_ERR_LMS_BAD_INPUT_DATA   -0x0011 /**< Bad data has been input to an LMS function */
+#define MBEDTLS_ERR_LMS_OUT_OF_PRIV_KEYS -0x0013 /**< Specified LMS key has utilised all of its private keys */
+#define MBEDTLS_ERR_LMS_VERIFY_FAILED    -0x0015 /**< LMS signature verification failed */
+#define MBEDTLS_ERR_LMS_ALLOC_FAILED     -0x0017 /**< LMS failed to allocate space for a private key */
+
+#define MBEDTLS_LMS_TYPE_LEN        (4)
+#define MBEDTLS_LMS_H_TREE_HEIGHT       (10)
+#define MBEDTLS_LMS_M_NODE_BYTES        (32)
+
+#define MBEDTLS_LMS_SIG_LEN (MBEDTLS_LMOTS_Q_LEAF_ID_LEN + MBEDTLS_LMOTS_SIG_LEN + \
+                             MBEDTLS_LMS_TYPE_LEN + MBEDTLS_LMS_H_TREE_HEIGHT * MBEDTLS_LMS_M_NODE_BYTES)
+
+#define MBEDTLS_LMS_PUBKEY_LEN (MBEDTLS_LMS_TYPE_LEN + MBEDTLS_LMOTS_TYPE_LEN + \
+                                MBEDTLS_LMOTS_I_KEY_ID_LEN + MBEDTLS_LMS_M_NODE_BYTES)
+
+#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_PUBKEY_TYPE_OFFSET      (0)
+#define MBEDTLS_LMS_PUBKEY_OTSTYPE_OFFSET   (MBEDTLS_LMS_PUBKEY_TYPE_OFFSET     + MBEDTLS_LMS_TYPE_LEN)
+#define MBEDTLS_LMS_PUBKEY_I_KEY_ID_OFFSET  (MBEDTLS_LMS_PUBKEY_OTSTYPE_OFFSET  + MBEDTLS_LMOTS_TYPE_LEN)
+#define MBEDTLS_LMS_PUBKEY_ROOT_NODE_OFFSET (MBEDTLS_LMS_PUBKEY_I_KEY_ID_OFFSET + MBEDTLS_LMOTS_I_KEY_ID_LEN)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+    MBEDTLS_LMS_SHA256_M32_H10 = 0x6,
+} mbedtls_lms_algorithm_type_t;
+
+
+typedef struct {
+    unsigned char MBEDTLS_PRIVATE(have_privkey);
+    unsigned char MBEDTLS_PRIVATE(have_pubkey);
+    unsigned char MBEDTLS_PRIVATE(I_key_identifier)[MBEDTLS_LMOTS_I_KEY_ID_LEN];
+    mbedtls_lms_algorithm_type_t MBEDTLS_PRIVATE(type);
+    mbedtls_lmots_algorithm_type_t MBEDTLS_PRIVATE(otstype);
+    unsigned int MBEDTLS_PRIVATE(q_next_usable_key);
+    mbedtls_lmots_context *MBEDTLS_PRIVATE(priv_keys);
+    unsigned char MBEDTLS_PRIVATE(T_1_pub_key)[MBEDTLS_LMS_M_NODE_BYTES];
+} mbedtls_lms_context;
+
+
+/**
+ * \brief                    This function initializes an LMS context
+ *
+ * \param ctx                The uninitialized LMS context that will then be
+ *                           initialized.
+ */
+void mbedtls_lms_init( mbedtls_lms_context *ctx );
+
+/**
+ * \brief                    This function uninitializes an LMS context
+ *
+ * \param ctx                The initialized LMS context that will then be
+ *                           uninitialized.
+ */
+void mbedtls_lms_free( mbedtls_lms_context *ctx );
+
+/**
+ * \brief                    This function sets the type of an LMS context
+ *
+ * \note                     The parameter set in the context will then be used
+ *                           for keygen operations etc.
+ *
+ * \param ctx                The initialized LMS context.
+ * \param type               The type that will be set in the context.
+ * \param otstype            The type of the LMOTS implementation used by this
+ *                           context.
+ */
+int mbedtls_lms_set_algorithm_type( mbedtls_lms_context *ctx,
+                                    mbedtls_lms_algorithm_type_t type,
+                                    mbedtls_lmots_algorithm_type_t otstype);
+
+/**
+ * \brief                    This function creates a LMS signature, using a
+ *                           LMOTS context that contains a private key.
+ *
+ * \note                     Before this function is called, the context must
+ *                           have been initialized and must contain a private
+ *                           key.
+ *
+ * \note                     Each of the LMOTS private keys inside a LMS private
+ *                           key can only be used once. If they are reused, then
+ *                           attackers may be able to forge signatures with that
+ *                           key. This is all handled transparently, but it is
+ *                           important to not perform copy operations on LMS
+ *                           contexts that contain private key material.
+ *
+ * \param ctx                The initialized LMS context from which the
+ *                           private key will be read.
+ * \param f_rng              The RNG function to be used for signature
+ *                           generation.
+ * \param p_rng              The RNG context to be passed to f_rng
+ * \param msg                The buffer from which the message will be read.
+ * \param msg_len            The size of the message that will be read.
+ * \param sig                The buf into which the signature will be stored.
+ *                           Must be at least #MBEDTLS_LMOTS_SIG_LEN in size.
+ *
+ * \return         \c 0 on success.
+ * \return         A non-zero error code on failure.
+ */
+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);
+
+/**
+ * \brief                    This function verifies a LMS signature, using a
+ *                           LMS context that contains a public key.
+ *
+ * \note                     Before this function is called, the context must
+ *                           have been initialized and must contain a public key
+ *                           (either by import or generation).
+ *
+ * \param ctx                The initialized LMS context from which the public
+ *                           key will be read.
+ * \param msg                The buffer from which the message will be read.
+ * \param msg_len            The size of the message that will be read.
+ * \param sig                The buf from which the signature will be read.
+ *                           #MBEDTLS_LMS_SIG_LEN bytes will be read from
+ *                           this.
+ *
+ * \return         \c 0 on successful verification.
+ * \return         A non-zero error code on failure.
+ */
+int mbedtls_lms_verify( const mbedtls_lms_context *ctx,
+                        const unsigned char *msg, unsigned int msg_len,
+                        const unsigned char *sig );
+
+/**
+ * \brief                    This function imports an LMOTS public key into a
+ *                           LMS context.
+ *
+ * \note                     Before this function is called, the context must
+ *                           have been initialized.
+ *
+ * \note                     See IETF RFC8554 for details of the encoding of
+ *                           this public key.
+ *
+ * \param ctx                The initialized LMS context store the key in.
+ * \param key                The buffer from which the key will be read.
+ *                           #MBEDTLS_LMS_PUBKEY_LEN bytes will be read from
+ *                           this.
+ *
+ * \return         \c 0 on success.
+ * \return         A non-zero error code on failure.
+ */
+int mbedtls_lms_import_pubkey( mbedtls_lms_context *ctx,
+                               const unsigned char *key );
+
+/**
+ * \brief                    This function exports an LMOTS public key from a
+ *                           LMS context that already contains a public key.
+ *
+ * \note                     Before this function is called, the context must
+ *                           have been initialized and the context must contain
+ *                           a public key.
+ *
+ * \note                     See IETF RFC8554 for details of the encoding of
+ *                           this public key.
+ *
+ * \param ctx                The initialized LMS context that contains the
+ *                           publc key.
+ * \param key                The buffer into which the key will be output. Must
+ *                           be at least #MBEDTLS_LMS_PUBKEY_LEN in size.
+ *
+ * \return         \c 0 on success.
+ * \return         A non-zero error code on failure.
+ */
+int mbedtls_lms_export_pubkey( mbedtls_lms_context *ctx,
+                               unsigned char *key );
+
+/**
+ * \brief                    This function generates an LMS public key from a
+ *                           LMS context that already contains a private key.
+ *
+ * \note                     Before this function is called, the context must
+ *                           have been initialized and the context must contain
+ *                           a private key.
+ *
+ * \param ctx                The initialized LMS context to generate the key
+ *                           from and store it into.
+ *
+ * \return         \c 0 on success.
+ * \return         A non-zero error code on failure.
+ */
+int mbedtls_lms_gen_pubkey( mbedtls_lms_context *ctx );
+
+/**
+ * \brief                    This function generates an LMS private key, and
+ *                           stores in into an LMS context.
+ *
+ * \note                     Before this function is called, the context must
+ *                           have been initialized and the type of the LMS
+ *                           context set using mbedtls_lmots_set_algorithm_type
+ *
+ * \note                     The seed must have at least 256 bits of entropy.
+ *
+ * \param ctx                The initialized LMOTS context to generate the key
+ *                           into.
+ * \param f_rng              The RNG function to be used to generate the key ID.
+ * \param p_rng              The RNG context to be passed to f_rng
+ * \param seed               The seed used to deterministically generate the
+ *                           key.
+ * \param seed_len           The length of the seed.
+ *
+ * \return         \c 0 on success.
+ * \return         A non-zero error code on failure.
+ */
+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 );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* MBEDTLS_LMS_H */