diff --git a/library/mps/error.h b/library/mps/error.h
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+++ b/library/mps/error.h
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+/*
+ *  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.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ */
+
+/**
+ * \file error.h
+ *
+ * \brief Error codes used by MPS
+ */
+
+#ifndef MBEDTLS_MPS_ERROR_H
+#define MBEDTLS_MPS_ERROR_H
+
+
+/* TODO: The error code allocation needs to be revisited:
+ *
+ * - Should we make (some of) the MPS Reader error codes public?
+ *   If so, we need to adjust MBEDTLS_READER_MAKE_ERROR() to hit
+ *   a gap in the Mbed TLS public error space.
+ *   If not, we have to make sure we don't forward those errors
+ *   at the level of the public API -- no risk at the moment as
+ *   long as MPS is an experimental component not accessible from
+ *   public API.
+ */
+
+#ifndef MBEDTLS_MPS_ERR_BASE
+#define MBEDTLS_MPS_ERR_BASE    ( 1 << 0 )
+#endif
+
+/**
+ * \name SECTION:       MPS Reader error codes
+ *
+ * \{
+ */
+
+#ifndef MBEDTLS_MPS_READER_ERR_BASE
+#define MBEDTLS_MPS_READER_ERR_BASE ( 1 << 7 )
+#endif
+
+#define MBEDTLS_MPS_READER_MAKE_ERROR(code) \
+    ( -( MBEDTLS_MPS_READER_ERR_BASE | (code) ) )
+
+/*! An attempt to reclaim the data buffer from a reader failed because
+ *  the user hasn't yet read and committed all of it. */
+#define MBEDTLS_ERR_MPS_READER_DATA_LEFT             MBEDTLS_MPS_READER_MAKE_ERROR( 0x1 )
+
+/*! An invalid argument was passed to the reader. */
+#define MBEDTLS_ERR_MPS_READER_INVALID_ARG           MBEDTLS_MPS_READER_MAKE_ERROR( 0x2 )
+
+/*! An attempt to move a reader to consuming mode through mbedtls_reader_feed()
+ *  after pausing failed because the provided data is not sufficient to serve the
+ *  the read requests that lead to the pausing. */
+#define MBEDTLS_ERR_MPS_READER_NEED_MORE             MBEDTLS_MPS_READER_MAKE_ERROR( 0x3 )
+
+/*! A read request failed because not enough data is available in the reader. */
+#define MBEDTLS_ERR_MPS_READER_OUT_OF_DATA           MBEDTLS_MPS_READER_MAKE_ERROR( 0x4 )
+
+/*!< A read request after pausing and reactivating the reader failed because
+ *   the request is not in line with the request made prior to pausing. The user
+ *   must not change it's 'strategy' after pausing and reactivating a reader. */
+#define MBEDTLS_ERR_MPS_READER_INCONSISTENT_REQUESTS MBEDTLS_MPS_READER_MAKE_ERROR( 0x5 )
+
+/*! An attempt to reclaim the data buffer from a reader fails because the reader
+ *  has no accumulator it can use to backup the data that hasn't been processed. */
+#define MBEDTLS_ERR_MPS_READER_NEED_ACCUMULATOR      MBEDTLS_MPS_READER_MAKE_ERROR( 0x6 )
+
+/*! An attempt to reclaim the data buffer from a reader fails beacuse the
+ *  accumulator passed to the reader is not large enough to hold both the
+ *  data that hasn't been processed and the excess of the last read-request. */
+#define MBEDTLS_ERR_MPS_READER_ACCUMULATOR_TOO_SMALL MBEDTLS_MPS_READER_MAKE_ERROR( 0x7 )
+
+/* \} name SECTION: MPS Reader error codes */
+
+#endif /* MBEDTLS_MPS_ERROR_H */