diff --git a/include/mbedcrypto/cipher.h b/include/mbedcrypto/cipher.h
new file mode 100644
index 0000000..43f8f68
--- /dev/null
+++ b/include/mbedcrypto/cipher.h
@@ -0,0 +1,773 @@
+/**
+ * \file cipher.h
+ *
+ * \brief This file contains an abstraction interface for use with the cipher
+ * primitives provided by the library. It provides a common interface to all of
+ * the available cipher operations.
+ *
+ * \author Adriaan de Jong <dejong@fox-it.com>
+ */
+/*
+ *  Copyright (C) 2006-2018, Arm Limited (or its affiliates), All Rights Reserved
+ *  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 Crypto (https://tls.mbed.org)
+ */
+
+#ifndef MBEDCRYPTO_CIPHER_H
+#define MBEDCRYPTO_CIPHER_H
+
+#if !defined(MBEDCRYPTO_CONFIG_FILE)
+#include "config.h"
+#else
+#include MBEDCRYPTO_CONFIG_FILE
+#endif
+
+#include <stddef.h>
+
+#if defined(MBEDCRYPTO_GCM_C) || defined(MBEDCRYPTO_CCM_C)
+#define MBEDCRYPTO_CIPHER_MODE_AEAD
+#endif
+
+#if defined(MBEDCRYPTO_CIPHER_MODE_CBC)
+#define MBEDCRYPTO_CIPHER_MODE_WITH_PADDING
+#endif
+
+#if defined(MBEDCRYPTO_ARC4_C)
+#define MBEDCRYPTO_CIPHER_MODE_STREAM
+#endif
+
+#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
+    !defined(inline) && !defined(__cplusplus)
+#define inline __inline
+#endif
+
+#define MBEDCRYPTO_ERR_CIPHER_FEATURE_UNAVAILABLE  -0x6080  /**< The selected feature is not available. */
+#define MBEDCRYPTO_ERR_CIPHER_BAD_INPUT_DATA       -0x6100  /**< Bad input parameters. */
+#define MBEDCRYPTO_ERR_CIPHER_ALLOC_FAILED         -0x6180  /**< Failed to allocate memory. */
+#define MBEDCRYPTO_ERR_CIPHER_INVALID_PADDING      -0x6200  /**< Input data contains invalid padding and is rejected. */
+#define MBEDCRYPTO_ERR_CIPHER_FULL_BLOCK_EXPECTED  -0x6280  /**< Decryption of block requires a full block. */
+#define MBEDCRYPTO_ERR_CIPHER_AUTH_FAILED          -0x6300  /**< Authentication failed (for AEAD modes). */
+#define MBEDCRYPTO_ERR_CIPHER_INVALID_CONTEXT      -0x6380  /**< The context is invalid. For example, because it was freed. */
+#define MBEDCRYPTO_ERR_CIPHER_HW_ACCEL_FAILED      -0x6400  /**< Cipher hardware accelerator failed. */
+
+#define MBEDCRYPTO_CIPHER_VARIABLE_IV_LEN     0x01    /**< Cipher accepts IVs of variable length. */
+#define MBEDCRYPTO_CIPHER_VARIABLE_KEY_LEN    0x02    /**< Cipher accepts keys of variable length. */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \brief     Supported cipher types.
+ *
+ * \warning   RC4 and DES are considered weak ciphers and their use
+ *            constitutes a security risk. Arm recommends considering stronger
+ *            ciphers instead.
+ */
+typedef enum {
+    MBEDCRYPTO_CIPHER_ID_NONE = 0,  /**< Placeholder to mark the end of cipher ID lists. */
+    MBEDCRYPTO_CIPHER_ID_NULL,      /**< The identity cipher, treated as a stream cipher. */
+    MBEDCRYPTO_CIPHER_ID_AES,       /**< The AES cipher. */
+    MBEDCRYPTO_CIPHER_ID_DES,       /**< The DES cipher. */
+    MBEDCRYPTO_CIPHER_ID_3DES,      /**< The Triple DES cipher. */
+    MBEDCRYPTO_CIPHER_ID_CAMELLIA,  /**< The Camellia cipher. */
+    MBEDCRYPTO_CIPHER_ID_BLOWFISH,  /**< The Blowfish cipher. */
+    MBEDCRYPTO_CIPHER_ID_ARC4,      /**< The RC4 cipher. */
+} mbedcrypto_cipher_id_t;
+
+/**
+ * \brief     Supported {cipher type, cipher mode} pairs.
+ *
+ * \warning   RC4 and DES are considered weak ciphers and their use
+ *            constitutes a security risk. Arm recommends considering stronger
+ *            ciphers instead.
+ */
+typedef enum {
+    MBEDCRYPTO_CIPHER_NONE = 0,             /**< Placeholder to mark the end of cipher-pair lists. */
+    MBEDCRYPTO_CIPHER_NULL,                 /**< The identity stream cipher. */
+    MBEDCRYPTO_CIPHER_AES_128_ECB,          /**< AES cipher with 128-bit ECB mode. */
+    MBEDCRYPTO_CIPHER_AES_192_ECB,          /**< AES cipher with 192-bit ECB mode. */
+    MBEDCRYPTO_CIPHER_AES_256_ECB,          /**< AES cipher with 256-bit ECB mode. */
+    MBEDCRYPTO_CIPHER_AES_128_CBC,          /**< AES cipher with 128-bit CBC mode. */
+    MBEDCRYPTO_CIPHER_AES_192_CBC,          /**< AES cipher with 192-bit CBC mode. */
+    MBEDCRYPTO_CIPHER_AES_256_CBC,          /**< AES cipher with 256-bit CBC mode. */
+    MBEDCRYPTO_CIPHER_AES_128_CFB128,       /**< AES cipher with 128-bit CFB128 mode. */
+    MBEDCRYPTO_CIPHER_AES_192_CFB128,       /**< AES cipher with 192-bit CFB128 mode. */
+    MBEDCRYPTO_CIPHER_AES_256_CFB128,       /**< AES cipher with 256-bit CFB128 mode. */
+    MBEDCRYPTO_CIPHER_AES_128_CTR,          /**< AES cipher with 128-bit CTR mode. */
+    MBEDCRYPTO_CIPHER_AES_192_CTR,          /**< AES cipher with 192-bit CTR mode. */
+    MBEDCRYPTO_CIPHER_AES_256_CTR,          /**< AES cipher with 256-bit CTR mode. */
+    MBEDCRYPTO_CIPHER_AES_128_GCM,          /**< AES cipher with 128-bit GCM mode. */
+    MBEDCRYPTO_CIPHER_AES_192_GCM,          /**< AES cipher with 192-bit GCM mode. */
+    MBEDCRYPTO_CIPHER_AES_256_GCM,          /**< AES cipher with 256-bit GCM mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_128_ECB,     /**< Camellia cipher with 128-bit ECB mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_192_ECB,     /**< Camellia cipher with 192-bit ECB mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_256_ECB,     /**< Camellia cipher with 256-bit ECB mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_128_CBC,     /**< Camellia cipher with 128-bit CBC mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_192_CBC,     /**< Camellia cipher with 192-bit CBC mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_256_CBC,     /**< Camellia cipher with 256-bit CBC mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_128_CFB128,  /**< Camellia cipher with 128-bit CFB128 mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_192_CFB128,  /**< Camellia cipher with 192-bit CFB128 mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_256_CFB128,  /**< Camellia cipher with 256-bit CFB128 mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_128_CTR,     /**< Camellia cipher with 128-bit CTR mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_192_CTR,     /**< Camellia cipher with 192-bit CTR mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_256_CTR,     /**< Camellia cipher with 256-bit CTR mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_128_GCM,     /**< Camellia cipher with 128-bit GCM mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_192_GCM,     /**< Camellia cipher with 192-bit GCM mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_256_GCM,     /**< Camellia cipher with 256-bit GCM mode. */
+    MBEDCRYPTO_CIPHER_DES_ECB,              /**< DES cipher with ECB mode. */
+    MBEDCRYPTO_CIPHER_DES_CBC,              /**< DES cipher with CBC mode. */
+    MBEDCRYPTO_CIPHER_DES_EDE_ECB,          /**< DES cipher with EDE ECB mode. */
+    MBEDCRYPTO_CIPHER_DES_EDE_CBC,          /**< DES cipher with EDE CBC mode. */
+    MBEDCRYPTO_CIPHER_DES_EDE3_ECB,         /**< DES cipher with EDE3 ECB mode. */
+    MBEDCRYPTO_CIPHER_DES_EDE3_CBC,         /**< DES cipher with EDE3 CBC mode. */
+    MBEDCRYPTO_CIPHER_BLOWFISH_ECB,         /**< Blowfish cipher with ECB mode. */
+    MBEDCRYPTO_CIPHER_BLOWFISH_CBC,         /**< Blowfish cipher with CBC mode. */
+    MBEDCRYPTO_CIPHER_BLOWFISH_CFB64,       /**< Blowfish cipher with CFB64 mode. */
+    MBEDCRYPTO_CIPHER_BLOWFISH_CTR,         /**< Blowfish cipher with CTR mode. */
+    MBEDCRYPTO_CIPHER_ARC4_128,             /**< RC4 cipher with 128-bit mode. */
+    MBEDCRYPTO_CIPHER_AES_128_CCM,          /**< AES cipher with 128-bit CCM mode. */
+    MBEDCRYPTO_CIPHER_AES_192_CCM,          /**< AES cipher with 192-bit CCM mode. */
+    MBEDCRYPTO_CIPHER_AES_256_CCM,          /**< AES cipher with 256-bit CCM mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_128_CCM,     /**< Camellia cipher with 128-bit CCM mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_192_CCM,     /**< Camellia cipher with 192-bit CCM mode. */
+    MBEDCRYPTO_CIPHER_CAMELLIA_256_CCM,     /**< Camellia cipher with 256-bit CCM mode. */
+} mbedcrypto_cipher_type_t;
+
+/** Supported cipher modes. */
+typedef enum {
+    MBEDCRYPTO_MODE_NONE = 0,               /**< None. */
+    MBEDCRYPTO_MODE_ECB,                    /**< The ECB cipher mode. */
+    MBEDCRYPTO_MODE_CBC,                    /**< The CBC cipher mode. */
+    MBEDCRYPTO_MODE_CFB,                    /**< The CFB cipher mode. */
+    MBEDCRYPTO_MODE_OFB,                    /**< The OFB cipher mode - unsupported. */
+    MBEDCRYPTO_MODE_CTR,                    /**< The CTR cipher mode. */
+    MBEDCRYPTO_MODE_GCM,                    /**< The GCM cipher mode. */
+    MBEDCRYPTO_MODE_STREAM,                 /**< The stream cipher mode. */
+    MBEDCRYPTO_MODE_CCM,                    /**< The CCM cipher mode. */
+} mbedcrypto_cipher_mode_t;
+
+/** Supported cipher padding types. */
+typedef enum {
+    MBEDCRYPTO_PADDING_PKCS7 = 0,     /**< PKCS7 padding (default).        */
+    MBEDCRYPTO_PADDING_ONE_AND_ZEROS, /**< ISO/IEC 7816-4 padding.         */
+    MBEDCRYPTO_PADDING_ZEROS_AND_LEN, /**< ANSI X.923 padding.             */
+    MBEDCRYPTO_PADDING_ZEROS,         /**< Zero padding (not reversible). */
+    MBEDCRYPTO_PADDING_NONE,          /**< Never pad (full blocks only).   */
+} mbedcrypto_cipher_padding_t;
+
+/** Type of operation. */
+typedef enum {
+    MBEDCRYPTO_OPERATION_NONE = -1,
+    MBEDCRYPTO_DECRYPT = 0,
+    MBEDCRYPTO_ENCRYPT,
+} mbedcrypto_operation_t;
+
+enum {
+    /** Undefined key length. */
+    MBEDCRYPTO_KEY_LENGTH_NONE = 0,
+    /** Key length, in bits (including parity), for DES keys. */
+    MBEDCRYPTO_KEY_LENGTH_DES  = 64,
+    /** Key length in bits, including parity, for DES in two-key EDE. */
+    MBEDCRYPTO_KEY_LENGTH_DES_EDE = 128,
+    /** Key length in bits, including parity, for DES in three-key EDE. */
+    MBEDCRYPTO_KEY_LENGTH_DES_EDE3 = 192,
+};
+
+/** Maximum length of any IV, in Bytes. */
+#define MBEDCRYPTO_MAX_IV_LENGTH      16
+/** Maximum block size of any cipher, in Bytes. */
+#define MBEDCRYPTO_MAX_BLOCK_LENGTH   16
+
+/**
+ * Base cipher information (opaque struct).
+ */
+typedef struct mbedcrypto_cipher_base_t mbedcrypto_cipher_base_t;
+
+/**
+ * CMAC context (opaque struct).
+ */
+typedef struct mbedcrypto_cmac_context_t mbedcrypto_cmac_context_t;
+
+/**
+ * Cipher information. Allows calling cipher functions
+ * in a generic way.
+ */
+typedef struct {
+    /** Full cipher identifier. For example,
+     * MBEDCRYPTO_CIPHER_AES_256_CBC.
+     */
+    mbedcrypto_cipher_type_t type;
+
+    /** The cipher mode. For example, MBEDCRYPTO_MODE_CBC. */
+    mbedcrypto_cipher_mode_t mode;
+
+    /** The cipher key length, in bits. This is the
+     * default length for variable sized ciphers.
+     * Includes parity bits for ciphers like DES.
+     */
+    unsigned int key_bitlen;
+
+    /** Name of the cipher. */
+    const char * name;
+
+    /** IV or nonce size, in Bytes.
+     * For ciphers that accept variable IV sizes,
+     * this is the recommended size.
+     */
+    unsigned int iv_size;
+
+    /** Bitflag comprised of MBEDCRYPTO_CIPHER_VARIABLE_IV_LEN and
+     *  MBEDCRYPTO_CIPHER_VARIABLE_KEY_LEN indicating whether the
+     *  cipher supports variable IV or variable key sizes, respectively.
+     */
+    int flags;
+
+    /** The block size, in Bytes. */
+    unsigned int block_size;
+
+    /** Struct for base cipher information and functions. */
+    const mbedcrypto_cipher_base_t *base;
+
+} mbedcrypto_cipher_info_t;
+
+/**
+ * Generic cipher context.
+ */
+typedef struct {
+    /** Information about the associated cipher. */
+    const mbedcrypto_cipher_info_t *cipher_info;
+
+    /** Key length to use. */
+    int key_bitlen;
+
+    /** Operation that the key of the context has been
+     * initialized for.
+     */
+    mbedcrypto_operation_t operation;
+
+#if defined(MBEDCRYPTO_CIPHER_MODE_WITH_PADDING)
+    /** Padding functions to use, if relevant for
+     * the specific cipher mode.
+     */
+    void (*add_padding)( unsigned char *output, size_t olen, size_t data_len );
+    int (*get_padding)( unsigned char *input, size_t ilen, size_t *data_len );
+#endif
+
+    /** Buffer for input that has not been processed yet. */
+    unsigned char unprocessed_data[MBEDCRYPTO_MAX_BLOCK_LENGTH];
+
+    /** Number of Bytes that have not been processed yet. */
+    size_t unprocessed_len;
+
+    /** Current IV or NONCE_COUNTER for CTR-mode. */
+    unsigned char iv[MBEDCRYPTO_MAX_IV_LENGTH];
+
+    /** IV size in Bytes, for ciphers with variable-length IVs. */
+    size_t iv_size;
+
+    /** The cipher-specific context. */
+    void *cipher_ctx;
+
+#if defined(MBEDCRYPTO_CMAC_C)
+    /** CMAC-specific context. */
+    mbedcrypto_cmac_context_t *cmac_ctx;
+#endif
+} mbedcrypto_cipher_context_t;
+
+/**
+ * \brief This function retrieves the list of ciphers supported by the generic
+ * cipher module.
+ *
+ * \return      A statically-allocated array of ciphers. The last entry
+ *              is zero.
+ */
+const int *mbedcrypto_cipher_list( void );
+
+/**
+ * \brief               This function retrieves the cipher-information
+ *                      structure associated with the given cipher name.
+ *
+ * \param cipher_name   Name of the cipher to search for.
+ *
+ * \return              The cipher information structure associated with the
+ *                      given \p cipher_name.
+ * \return              NULL if the associated cipher information is not found.
+ */
+const mbedcrypto_cipher_info_t *mbedcrypto_cipher_info_from_string( const char *cipher_name );
+
+/**
+ * \brief               This function retrieves the cipher-information
+ *                      structure associated with the given cipher type.
+ *
+ * \param cipher_type   Type of the cipher to search for.
+ *
+ * \return              The cipher information structure associated with the
+ *                      given \p cipher_type.
+ * \return              NULL if the associated cipher information is not found.
+ */
+const mbedcrypto_cipher_info_t *mbedcrypto_cipher_info_from_type( const mbedcrypto_cipher_type_t cipher_type );
+
+/**
+ * \brief               This function retrieves the cipher-information
+ *                      structure associated with the given cipher ID,
+ *                      key size and mode.
+ *
+ * \param cipher_id     The ID of the cipher to search for. For example,
+ *                      #MBEDCRYPTO_CIPHER_ID_AES.
+ * \param key_bitlen    The length of the key in bits.
+ * \param mode          The cipher mode. For example, #MBEDCRYPTO_MODE_CBC.
+ *
+ * \return              The cipher information structure associated with the
+ *                      given \p cipher_id.
+ * \return              NULL if the associated cipher information is not found.
+ */
+const mbedcrypto_cipher_info_t *mbedcrypto_cipher_info_from_values( const mbedcrypto_cipher_id_t cipher_id,
+                                              int key_bitlen,
+                                              const mbedcrypto_cipher_mode_t mode );
+
+/**
+ * \brief               This function initializes a \p cipher_context as NONE.
+ */
+void mbedcrypto_cipher_init( mbedcrypto_cipher_context_t *ctx );
+
+/**
+ * \brief               This function frees and clears the cipher-specific
+ *                      context of \p ctx. Freeing \p ctx itself remains the
+ *                      responsibility of the caller.
+ */
+void mbedcrypto_cipher_free( mbedcrypto_cipher_context_t *ctx );
+
+
+/**
+ * \brief               This function initializes and fills the cipher-context
+ *                      structure with the appropriate values. It also clears
+ *                      the structure.
+ *
+ * \param ctx           The context to initialize. May not be NULL.
+ * \param cipher_info   The cipher to use.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_BAD_INPUT_DATA on
+ *                      parameter-verification failure.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_ALLOC_FAILED if allocation of the
+ *                      cipher-specific context fails.
+ *
+ * \internal Currently, the function also clears the structure.
+ * In future versions, the caller will be required to call
+ * mbedcrypto_cipher_init() on the structure first.
+ */
+int mbedcrypto_cipher_setup( mbedcrypto_cipher_context_t *ctx, const mbedcrypto_cipher_info_t *cipher_info );
+
+/**
+ * \brief        This function returns the block size of the given cipher.
+ *
+ * \param ctx    The context of the cipher. Must be initialized.
+ *
+ * \return       The size of the blocks of the cipher.
+ * \return       0 if \p ctx has not been initialized.
+ */
+static inline unsigned int mbedcrypto_cipher_get_block_size( const mbedcrypto_cipher_context_t *ctx )
+{
+    if( NULL == ctx || NULL == ctx->cipher_info )
+        return 0;
+
+    return ctx->cipher_info->block_size;
+}
+
+/**
+ * \brief        This function returns the mode of operation for
+ *               the cipher. For example, MBEDCRYPTO_MODE_CBC.
+ *
+ * \param ctx    The context of the cipher. Must be initialized.
+ *
+ * \return       The mode of operation.
+ * \return       #MBEDCRYPTO_MODE_NONE if \p ctx has not been initialized.
+ */
+static inline mbedcrypto_cipher_mode_t mbedcrypto_cipher_get_cipher_mode( const mbedcrypto_cipher_context_t *ctx )
+{
+    if( NULL == ctx || NULL == ctx->cipher_info )
+        return MBEDCRYPTO_MODE_NONE;
+
+    return ctx->cipher_info->mode;
+}
+
+/**
+ * \brief       This function returns the size of the IV or nonce
+ *              of the cipher, in Bytes.
+ *
+ * \param ctx   The context of the cipher. Must be initialized.
+ *
+ * \return      The recommended IV size if no IV has been set.
+ * \return      \c 0 for ciphers not using an IV or a nonce.
+ * \return      The actual size if an IV has been set.
+ */
+static inline int mbedcrypto_cipher_get_iv_size( const mbedcrypto_cipher_context_t *ctx )
+{
+    if( NULL == ctx || NULL == ctx->cipher_info )
+        return 0;
+
+    if( ctx->iv_size != 0 )
+        return (int) ctx->iv_size;
+
+    return (int) ctx->cipher_info->iv_size;
+}
+
+/**
+ * \brief               This function returns the type of the given cipher.
+ *
+ * \param ctx           The context of the cipher. Must be initialized.
+ *
+ * \return              The type of the cipher.
+ * \return              #MBEDCRYPTO_CIPHER_NONE if \p ctx has not been initialized.
+ */
+static inline mbedcrypto_cipher_type_t mbedcrypto_cipher_get_type( const mbedcrypto_cipher_context_t *ctx )
+{
+    if( NULL == ctx || NULL == ctx->cipher_info )
+        return MBEDCRYPTO_CIPHER_NONE;
+
+    return ctx->cipher_info->type;
+}
+
+/**
+ * \brief               This function returns the name of the given cipher
+ *                      as a string.
+ *
+ * \param ctx           The context of the cipher. Must be initialized.
+ *
+ * \return              The name of the cipher.
+ * \return              NULL if \p ctx has not been not initialized.
+ */
+static inline const char *mbedcrypto_cipher_get_name( const mbedcrypto_cipher_context_t *ctx )
+{
+    if( NULL == ctx || NULL == ctx->cipher_info )
+        return 0;
+
+    return ctx->cipher_info->name;
+}
+
+/**
+ * \brief               This function returns the key length of the cipher.
+ *
+ * \param ctx           The context of the cipher. Must be initialized.
+ *
+ * \return              The key length of the cipher in bits.
+ * \return              #MBEDCRYPTO_KEY_LENGTH_NONE if ctx \p has not been
+ *                      initialized.
+ */
+static inline int mbedcrypto_cipher_get_key_bitlen( const mbedcrypto_cipher_context_t *ctx )
+{
+    if( NULL == ctx || NULL == ctx->cipher_info )
+        return MBEDCRYPTO_KEY_LENGTH_NONE;
+
+    return (int) ctx->cipher_info->key_bitlen;
+}
+
+/**
+ * \brief          This function returns the operation of the given cipher.
+ *
+ * \param ctx      The context of the cipher. Must be initialized.
+ *
+ * \return         The type of operation: #MBEDCRYPTO_ENCRYPT or #MBEDCRYPTO_DECRYPT.
+ * \return         #MBEDCRYPTO_OPERATION_NONE if \p ctx has not been initialized.
+ */
+static inline mbedcrypto_operation_t mbedcrypto_cipher_get_operation( const mbedcrypto_cipher_context_t *ctx )
+{
+    if( NULL == ctx || NULL == ctx->cipher_info )
+        return MBEDCRYPTO_OPERATION_NONE;
+
+    return ctx->operation;
+}
+
+/**
+ * \brief               This function sets the key to use with the given context.
+ *
+ * \param ctx           The generic cipher context. May not be NULL. Must have
+ *                      been initialized using mbedcrypto_cipher_info_from_type()
+ *                      or mbedcrypto_cipher_info_from_string().
+ * \param key           The key to use.
+ * \param key_bitlen    The key length to use, in bits.
+ * \param operation     The operation that the key will be used for:
+ *                      #MBEDCRYPTO_ENCRYPT or #MBEDCRYPTO_DECRYPT.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_BAD_INPUT_DATA on
+ *                      parameter-verification failure.
+ * \return              A cipher-specific error code on failure.
+ */
+int mbedcrypto_cipher_setkey( mbedcrypto_cipher_context_t *ctx, const unsigned char *key,
+                   int key_bitlen, const mbedcrypto_operation_t operation );
+
+#if defined(MBEDCRYPTO_CIPHER_MODE_WITH_PADDING)
+/**
+ * \brief               This function sets the padding mode, for cipher modes
+ *                      that use padding.
+ *
+ *                      The default passing mode is PKCS7 padding.
+ *
+ * \param ctx           The generic cipher context.
+ * \param mode          The padding mode.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_FEATURE_UNAVAILABLE
+ *                      if the selected padding mode is not supported.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_BAD_INPUT_DATA if the cipher mode
+ *                      does not support padding.
+ */
+int mbedcrypto_cipher_set_padding_mode( mbedcrypto_cipher_context_t *ctx, mbedcrypto_cipher_padding_t mode );
+#endif /* MBEDCRYPTO_CIPHER_MODE_WITH_PADDING */
+
+/**
+ * \brief           This function sets the initialization vector (IV)
+ *                  or nonce.
+ *
+ * \note            Some ciphers do not use IVs nor nonce. For these
+ *                  ciphers, this function has no effect.
+ *
+ * \param ctx       The generic cipher context.
+ * \param iv        The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
+ * \param iv_len    The IV length for ciphers with variable-size IV.
+ *                  This parameter is discarded by ciphers with fixed-size IV.
+ *
+ * \return          \c 0 on success.
+ * \return          #MBEDCRYPTO_ERR_CIPHER_BAD_INPUT_DATA on
+ *                  parameter-verification failure.
+ */
+int mbedcrypto_cipher_set_iv( mbedcrypto_cipher_context_t *ctx,
+                   const unsigned char *iv, size_t iv_len );
+
+/**
+ * \brief         This function resets the cipher state.
+ *
+ * \param ctx     The generic cipher context.
+ *
+ * \return        \c 0 on success.
+ * \return        #MBEDCRYPTO_ERR_CIPHER_BAD_INPUT_DATA on
+ *                parameter-verification failure.
+ */
+int mbedcrypto_cipher_reset( mbedcrypto_cipher_context_t *ctx );
+
+#if defined(MBEDCRYPTO_GCM_C)
+/**
+ * \brief               This function adds additional data for AEAD ciphers.
+ *                      Only supported with GCM. Must be called
+ *                      exactly once, after mbedcrypto_cipher_reset().
+ *
+ * \param ctx           The generic cipher context.
+ * \param ad            The additional data to use.
+ * \param ad_len        the Length of \p ad.
+ *
+ * \return              \c 0 on success.
+ * \return              A specific error code on failure.
+ */
+int mbedcrypto_cipher_update_ad( mbedcrypto_cipher_context_t *ctx,
+                      const unsigned char *ad, size_t ad_len );
+#endif /* MBEDCRYPTO_GCM_C */
+
+/**
+ * \brief               The generic cipher update function. It encrypts or
+ *                      decrypts using the given cipher context. Writes as
+ *                      many block-sized blocks of data as possible to output.
+ *                      Any data that cannot be written immediately is either
+ *                      added to the next block, or flushed when
+ *                      mbedcrypto_cipher_finish() is called.
+ *                      Exception: For MBEDCRYPTO_MODE_ECB, expects a single block
+ *                      in size. For example, 16 Bytes for AES.
+ *
+ * \note                If the underlying cipher is used in GCM mode, all calls
+ *                      to this function, except for the last one before
+ *                      mbedcrypto_cipher_finish(), must have \p ilen as a
+ *                      multiple of the block size of the cipher.
+ *
+ * \param ctx           The generic cipher context.
+ * \param input         The buffer holding the input data.
+ * \param ilen          The length of the input data.
+ * \param output        The buffer for the output data. Must be able to hold at
+ *                      least \p ilen + block_size. Must not be the same buffer
+ *                      as input.
+ * \param olen          The length of the output data, to be updated with the
+ *                      actual number of Bytes written.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_BAD_INPUT_DATA on
+ *                      parameter-verification failure.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_FEATURE_UNAVAILABLE on an
+ *                      unsupported mode for a cipher.
+ * \return              A cipher-specific error code on failure.
+ */
+int mbedcrypto_cipher_update( mbedcrypto_cipher_context_t *ctx, const unsigned char *input,
+                   size_t ilen, unsigned char *output, size_t *olen );
+
+/**
+ * \brief               The generic cipher finalization function. If data still
+ *                      needs to be flushed from an incomplete block, the data
+ *                      contained in it is padded to the size of
+ *                      the last block, and written to the \p output buffer.
+ *
+ * \param ctx           The generic cipher context.
+ * \param output        The buffer to write data to. Needs block_size available.
+ * \param olen          The length of the data written to the \p output buffer.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_BAD_INPUT_DATA on
+ *                      parameter-verification failure.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_FULL_BLOCK_EXPECTED on decryption
+ *                      expecting a full block but not receiving one.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_INVALID_PADDING on invalid padding
+ *                      while decrypting.
+ * \return              A cipher-specific error code on failure.
+ */
+int mbedcrypto_cipher_finish( mbedcrypto_cipher_context_t *ctx,
+                   unsigned char *output, size_t *olen );
+
+#if defined(MBEDCRYPTO_GCM_C)
+/**
+ * \brief               This function writes a tag for AEAD ciphers.
+ *                      Only supported with GCM.
+ *                      Must be called after mbedcrypto_cipher_finish().
+ *
+ * \param ctx           The generic cipher context.
+ * \param tag           The buffer to write the tag to.
+ * \param tag_len       The length of the tag to write.
+ *
+ * \return              \c 0 on success.
+ * \return              A specific error code on failure.
+ */
+int mbedcrypto_cipher_write_tag( mbedcrypto_cipher_context_t *ctx,
+                      unsigned char *tag, size_t tag_len );
+
+/**
+ * \brief               This function checks the tag for AEAD ciphers.
+ *                      Only supported with GCM.
+ *                      Must be called after mbedcrypto_cipher_finish().
+ *
+ * \param ctx           The generic cipher context.
+ * \param tag           The buffer holding the tag.
+ * \param tag_len       The length of the tag to check.
+ *
+ * \return              \c 0 on success.
+ * \return              A specific error code on failure.
+ */
+int mbedcrypto_cipher_check_tag( mbedcrypto_cipher_context_t *ctx,
+                      const unsigned char *tag, size_t tag_len );
+#endif /* MBEDCRYPTO_GCM_C */
+
+/**
+ * \brief               The generic all-in-one encryption/decryption function,
+ *                      for all ciphers except AEAD constructs.
+ *
+ * \param ctx           The generic cipher context.
+ * \param iv            The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
+ * \param iv_len        The IV length for ciphers with variable-size IV.
+ *                      This parameter is discarded by ciphers with fixed-size
+ *                      IV.
+ * \param input         The buffer holding the input data.
+ * \param ilen          The length of the input data.
+ * \param output        The buffer for the output data. Must be able to hold at
+ *                      least \p ilen + block_size. Must not be the same buffer
+ *                      as input.
+ * \param olen          The length of the output data, to be updated with the
+ *                      actual number of Bytes written.
+ *
+ * \note                Some ciphers do not use IVs nor nonce. For these
+ *                      ciphers, use \p iv = NULL and \p iv_len = 0.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_BAD_INPUT_DATA on
+ *                      parameter-verification failure.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_FULL_BLOCK_EXPECTED on decryption
+ *                      expecting a full block but not receiving one.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_INVALID_PADDING on invalid padding
+ *                      while decrypting.
+ * \return              A cipher-specific error code on failure.
+ */
+int mbedcrypto_cipher_crypt( mbedcrypto_cipher_context_t *ctx,
+                  const unsigned char *iv, size_t iv_len,
+                  const unsigned char *input, size_t ilen,
+                  unsigned char *output, size_t *olen );
+
+#if defined(MBEDCRYPTO_CIPHER_MODE_AEAD)
+/**
+ * \brief               The generic autenticated encryption (AEAD) function.
+ *
+ * \param ctx           The generic cipher context.
+ * \param iv            The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
+ * \param iv_len        The IV length for ciphers with variable-size IV.
+ *                      This parameter is discarded by ciphers with fixed-size IV.
+ * \param ad            The additional data to authenticate.
+ * \param ad_len        The length of \p ad.
+ * \param input         The buffer holding the input data.
+ * \param ilen          The length of the input data.
+ * \param output        The buffer for the output data.
+ *                      Must be able to hold at least \p ilen.
+ * \param olen          The length of the output data, to be updated with the
+ *                      actual number of Bytes written.
+ * \param tag           The buffer for the authentication tag.
+ * \param tag_len       The desired length of the authentication tag.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_BAD_INPUT_DATA on
+ *                      parameter-verification failure.
+ * \return              A cipher-specific error code on failure.
+ */
+int mbedcrypto_cipher_auth_encrypt( mbedcrypto_cipher_context_t *ctx,
+                         const unsigned char *iv, size_t iv_len,
+                         const unsigned char *ad, size_t ad_len,
+                         const unsigned char *input, size_t ilen,
+                         unsigned char *output, size_t *olen,
+                         unsigned char *tag, size_t tag_len );
+
+/**
+ * \brief               The generic autenticated decryption (AEAD) function.
+ *
+ * \note                If the data is not authentic, then the output buffer
+ *                      is zeroed out to prevent the unauthentic plaintext being
+ *                      used, making this interface safer.
+ *
+ * \param ctx           The generic cipher context.
+ * \param iv            The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
+ * \param iv_len        The IV length for ciphers with variable-size IV.
+ *                      This parameter is discarded by ciphers with fixed-size IV.
+ * \param ad            The additional data to be authenticated.
+ * \param ad_len        The length of \p ad.
+ * \param input         The buffer holding the input data.
+ * \param ilen          The length of the input data.
+ * \param output        The buffer for the output data.
+ *                      Must be able to hold at least \p ilen.
+ * \param olen          The length of the output data, to be updated with the
+ *                      actual number of Bytes written.
+ * \param tag           The buffer holding the authentication tag.
+ * \param tag_len       The length of the authentication tag.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_BAD_INPUT_DATA on
+ *                      parameter-verification failure.
+ * \return              #MBEDCRYPTO_ERR_CIPHER_AUTH_FAILED if data is not authentic.
+ * \return              A cipher-specific error code on failure.
+ */
+int mbedcrypto_cipher_auth_decrypt( mbedcrypto_cipher_context_t *ctx,
+                         const unsigned char *iv, size_t iv_len,
+                         const unsigned char *ad, size_t ad_len,
+                         const unsigned char *input, size_t ilen,
+                         unsigned char *output, size_t *olen,
+                         const unsigned char *tag, size_t tag_len );
+#endif /* MBEDCRYPTO_CIPHER_MODE_AEAD */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* MBEDCRYPTO_CIPHER_H */