diff --git a/include/mbedtls/lmots.h b/include/mbedtls/lmots.h
new file mode 100644
index 0000000..a177ad4
--- /dev/null
+++ b/include/mbedtls/lmots.h
@@ -0,0 +1,292 @@
+/**
+ * \file lmots.h
+ *
+ * \brief This file provides an API for the LM-OTS post-quantum-safe one-time
+ *        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_LMOTS_H
+#define MBEDTLS_LMOTS_H
+
+#include "mbedtls/private_access.h"
+
+#include <stdint.h>
+#include <stddef.h>
+
+#define MBEDTLS_ERR_LMOTS_BAD_INPUT_DATA -0x0076 /**< Bad data has been input to an LMOTS function */
+#define MBEDTLS_ERR_LMOTS_VERIFY_FAILED  -0x0078 /**< LMOTS signature verification failed */
+
+#define MBEDTLS_LMOTS_N_HASH_LEN            (32)
+#define MBEDTLS_LMOTS_P_SIG_SYMBOL_LEN      (34)
+#define MBEDTLS_LMOTS_TYPE_LEN              (4)
+#define MBEDTLS_LMOTS_C_RANDOM_VALUE_LEN    (MBEDTLS_LMOTS_N_HASH_LEN)
+#define MBEDTLS_LMOTS_I_KEY_ID_LEN          (16)
+#define MBEDTLS_LMOTS_Q_LEAF_ID_LEN         (4)
+
+#define MBEDTLS_LMOTS_SIG_LEN (MBEDTLS_LMOTS_TYPE_LEN + MBEDTLS_LMOTS_C_RANDOM_VALUE_LEN + \
+                               (MBEDTLS_LMOTS_P_SIG_SYMBOL_LEN * MBEDTLS_LMOTS_N_HASH_LEN))
+
+#define MBEDTLS_LMOTS_PUBKEY_LEN (MBEDTLS_LMOTS_TYPE_LEN + MBEDTLS_LMOTS_I_KEY_ID_LEN + \
+                                  MBEDTLS_LMOTS_Q_LEAF_ID_LEN + MBEDTLS_LMOTS_N_HASH_LEN)
+
+#define MBEDTLS_LMOTS_SIG_TYPE_OFFSET      (0)
+#define MBEDTLS_LMOTS_SIG_C_RANDOM_OFFSET  (MBEDTLS_LMOTS_SIG_TYPE_OFFSET     + MBEDTLS_LMOTS_TYPE_LEN)
+#define MBEDTLS_LMOTS_SIG_SIGNATURE_OFFSET (MBEDTLS_LMOTS_SIG_C_RANDOM_OFFSET + MBEDTLS_LMOTS_C_RANDOM_VALUE_LEN)
+
+#define MBEDTLS_LMOTS_PUBKEY_TYPE_OFFSET      (0)
+#define MBEDTLS_LMOTS_PUBKEY_I_KEY_ID_OFFSET  (MBEDTLS_LMOTS_PUBKEY_TYPE_OFFSET      + MBEDTLS_LMOTS_TYPE_LEN)
+#define MBEDTLS_LMOTS_PUBKEY_Q_LEAF_ID_OFFSET (MBEDTLS_LMOTS_PUBKEY_I_KEY_ID_OFFSET  + MBEDTLS_LMOTS_I_KEY_ID_LEN)
+#define MBEDTLS_LMOTS_PUBKEY_KEY_HASH_OFFSET  (MBEDTLS_LMOTS_PUBKEY_Q_LEAF_ID_OFFSET + MBEDTLS_LMOTS_Q_LEAF_ID_LEN)
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* We are only implementing a subset of the types, particularly n32_w8, for the
+ * sake of simplicty
+ */
+typedef enum {
+    MBEDTLS_LMOTS_SHA256_N32_W8 = 4
+} mbedtls_lmots_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]);
+    unsigned int MBEDTLS_PRIVATE(q_leaf_identifier);
+    unsigned char MBEDTLS_PRIVATE(q_leaf_identifier_bytes)[MBEDTLS_LMOTS_Q_LEAF_ID_LEN];
+    mbedtls_lmots_algorithm_type_t MBEDTLS_PRIVATE(type);
+    unsigned char MBEDTLS_PRIVATE(priv_key[MBEDTLS_LMOTS_P_SIG_SYMBOL_LEN][32]);
+    unsigned char MBEDTLS_PRIVATE(pub_key[32]);
+} mbedtls_lmots_context;
+
+
+/**
+ * \brief                    This function initializes an LMOTS context
+ *
+ * \param ctx                The uninitialized LMOTS context that will then be
+ *                           initialized.
+ */
+void mbedtls_lmots_init( mbedtls_lmots_context *ctx );
+
+/**
+ * \brief                    This function uninitializes an LMOTS context
+ *
+ * \param ctx                The initialized LMOTS context that will then be
+ *                           uninitialized.
+ */
+void mbedtls_lmots_free( mbedtls_lmots_context *ctx );
+
+/**
+ * \brief                    This function sets the type of an LMOTS context
+ *
+ * \note                     The parameter set in the context will then be used
+ *                           for keygen operations etc.
+ *
+ * \param ctx                The initialized LMOTS context.
+ * \param type               The type that will be set in the context.
+ */
+int mbedtls_lmots_set_algorithm_type( mbedtls_lmots_context *ctx,
+                                      mbedtls_lmots_algorithm_type_t type );
+
+/**
+ * \brief                    This function creates a candidate public key from
+ *                           an LMOTS signature. This can then be compared to
+ *                           the real public key to determine the validity of
+ *                           the signature.
+ *
+ * \note                     This function is exposed publicly to be used in LMS
+ *                           signature verification, it is expected that
+ *                           mbedtls_lmots_verify will be used for LMOTS
+ *                           signature verification.
+ *
+ * \param I_key_identifier   The key identifier of the key, as a 16 byte
+ *                           bytestring.
+ * \param q_leaf_identifier  The leaf identifier of key. If this LMOTS key is
+ *                           not being used as part of an LMS key, this should
+ *                           be set to 0.
+ * \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 buff from which the signature will be read.
+ *                           MBEDTLS_LMOTS_SIG_LEN bytes will be read from this.
+ * \param out                The buffer where the candidate public key will be
+ *                           stored. Must be at least #MBEDTLS_LMOTS_N_HASH_LEN
+ *                           bytes in size.
+ *
+ * \return         \c 0 on success.
+ * \return         A non-zero error code on failure.
+ */
+int mbedtls_lmots_generate_pub_key_candidate( const unsigned char I_key_identifier[MBEDTLS_LMOTS_I_KEY_ID_LEN],
+                                              const unsigned char q_leaf_identifier[MBEDTLS_LMOTS_Q_LEAF_ID_LEN],
+                                              const unsigned char  *msg,
+                                              size_t msg_len,
+                                              const unsigned char *sig,
+                                              unsigned char *out );
+
+/**
+ * \brief                    This function creates a LMOTS 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                     LMOTS private keys can only be used once, otherwise
+ *                           attackers may be able to create forged signatures.
+ *                           If the signing operation is successful, the private
+ *                           key in the context will be erased, and no further
+ *                           signing will be possible until another private key
+ *                           is loaded
+ *
+ * \param ctx                The initialized LMOTS 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_lmots_sign( mbedtls_lmots_context *ctx,
+                        int (*f_rng)(void *, unsigned char *, size_t),
+                        void *p_rng, const unsigned char *msg, size_t msg_len,
+                        unsigned char *sig );
+
+/**
+ * \brief                    This function verifies a LMOTS signature, using a
+ *                           LMOTS 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 LMOTS 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_LMOTS_SIG_LEN bytes will be read from
+ *                           this.
+ *
+ * \return         \c 0 on successful verification.
+ * \return         A non-zero error code on failure.
+ */
+int mbedtls_lmots_verify( mbedtls_lmots_context *ctx, const unsigned char *msg,
+                          size_t msg_len, const unsigned char *sig );
+
+/**
+ * \brief                    This function imports an LMOTS public key into a
+ *                           LMOTS 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 LMOTS context store the key in.
+ * \param key                The buffer from which the key will be read.
+ *                           #MBEDTLS_LMOTS_PUBKEY_LEN bytes will be read from
+ *                           this.
+ *
+ * \return         \c 0 on success.
+ * \return         A non-zero error code on failure.
+ */
+int mbedtls_lmots_import_pubkey( mbedtls_lmots_context *ctx,
+                                 const unsigned char *key );
+
+/**
+ * \brief                    This function exports an LMOTS public key from a
+ *                           LMOTS 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 LMOTS context that contains the
+ *                           publc key.
+ * \param key                The buffer into which the key will be output. Must
+ *                           be at least #MBEDTLS_LMOTS_PUBKEY_LEN in size.
+ *
+ * \return         \c 0 on success.
+ * \return         A non-zero error code on failure.
+ */
+int mbedtls_lmots_export_pubkey( mbedtls_lmots_context *ctx,
+                                 unsigned char *key );
+
+/**
+ * \brief                    This function generates an LMOTS public key from a
+ *                           LMOTS 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 LMOTS 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_lmots_gen_pubkey( mbedtls_lmots_context *ctx );
+
+/**
+ * \brief                    This function generates an LMOTS private key, and
+ *                           stores in into an LMOTS context.
+ *
+ * \note                     Before this function is called, the context must
+ *                           have been initialized and the type of the LMOTS
+ *                           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 I_key_identifier   The key identifier of the key, as a 16 byte
+ *                           bytestring.
+ * \param q_leaf_identifier  The leaf identifier of key. If this LMOTS key is
+ *                           not being used as part of an LMS key, this should
+ *                           be set to 0.
+ * \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_lmots_gen_privkey( mbedtls_lmots_context *ctx,
+                               const unsigned char I_key_identifier[MBEDTLS_LMOTS_I_KEY_ID_LEN],
+                               unsigned int q_leaf_identifier,
+                               const unsigned char *seed,
+                               size_t seed_len );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* MBEDTLS_LMOTS_H */