diff --git a/include/mbedtls/aria.h b/include/mbedtls/aria.h
index 483d4c2..1e8956e 100644
--- a/include/mbedtls/aria.h
+++ b/include/mbedtls/aria.h
@@ -39,6 +39,8 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "platform_util.h"
+
 #define MBEDTLS_ARIA_ENCRYPT     1 /**< ARIA encryption. */
 #define MBEDTLS_ARIA_DECRYPT     0 /**< ARIA decryption. */
 
@@ -46,8 +48,12 @@
 #define MBEDTLS_ARIA_MAX_ROUNDS  16 /**< Maxiumum number of rounds in ARIA. */
 #define MBEDTLS_ARIA_MAX_KEYSIZE 32 /**< Maximum size of an ARIA key in bytes. */
 
-#define MBEDTLS_ERR_ARIA_INVALID_KEY_LENGTH   -0x005C  /**< Invalid key length. */
-#define MBEDTLS_ERR_ARIA_INVALID_INPUT_LENGTH -0x005E  /**< Invalid data input length. */
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+#define MBEDTLS_ERR_ARIA_INVALID_KEY_LENGTH   MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( -0x005C )
+#endif /* !MBEDTLS_DEPRECATED_REMOVED */
+#define MBEDTLS_ERR_ARIA_BAD_INPUT_DATA -0x005C /**< Bad input data. */
+
+#define MBEDTLS_ERR_ARIA_INVALID_INPUT_LENGTH -0x005E /**< Invalid data input length. */
 
 /* MBEDTLS_ERR_ARIA_FEATURE_UNAVAILABLE is deprecated and should not be used.
  */
@@ -85,14 +91,16 @@
  *                 It must be the first API called before using
  *                 the context.
  *
- * \param ctx      The ARIA context to initialize.
+ * \param ctx      The ARIA context to initialize. This must not be \c NULL.
  */
 void mbedtls_aria_init( mbedtls_aria_context *ctx );
 
 /**
  * \brief          This function releases and clears the specified ARIA context.
  *
- * \param ctx      The ARIA context to clear.
+ * \param ctx      The ARIA context to clear. This may be \c NULL, in which
+ *                 case this function returns immediately. If it is not \c NULL,
+ *                 it must point to an initialized ARIA context.
  */
 void mbedtls_aria_free( mbedtls_aria_context *ctx );
 
@@ -100,14 +108,16 @@
  * \brief          This function sets the encryption key.
  *
  * \param ctx      The ARIA context to which the key should be bound.
- * \param key      The encryption key.
- * \param keybits  The size of data passed in bits. Valid options are:
+ *                 This must be initialized.
+ * \param key      The encryption key. This must be a readable buffer
+ *                 of size \p keybits Bits.
+ * \param keybits  The size of \p key in Bits. Valid options are:
  *                 <ul><li>128 bits</li>
  *                 <li>192 bits</li>
  *                 <li>256 bits</li></ul>
  *
- * \return         \c 0 on success or #MBEDTLS_ERR_ARIA_INVALID_KEY_LENGTH
- *                 on failure.
+ * \return         \c 0 on success.
+ * \return         A negative error code on failure.
  */
 int mbedtls_aria_setkey_enc( mbedtls_aria_context *ctx,
                              const unsigned char *key,
@@ -117,13 +127,16 @@
  * \brief          This function sets the decryption key.
  *
  * \param ctx      The ARIA context to which the key should be bound.
- * \param key      The decryption key.
+ *                 This must be initialized.
+ * \param key      The decryption key. This must be a readable buffer
+ *                 of size \p keybits Bits.
  * \param keybits  The size of data passed. Valid options are:
  *                 <ul><li>128 bits</li>
  *                 <li>192 bits</li>
  *                 <li>256 bits</li></ul>
  *
- * \return         \c 0 on success, or #MBEDTLS_ERR_ARIA_INVALID_KEY_LENGTH on failure.
+ * \return         \c 0 on success.
+ * \return         A negative error code on failure.
  */
 int mbedtls_aria_setkey_dec( mbedtls_aria_context *ctx,
                              const unsigned char *key,
@@ -142,10 +155,12 @@
  *                 call to this API with the same context.
  *
  * \param ctx      The ARIA context to use for encryption or decryption.
+ *                 This must be initialized and bound to a key.
  * \param input    The 16-Byte buffer holding the input data.
  * \param output   The 16-Byte buffer holding the output data.
 
  * \return         \c 0 on success.
+ * \return         A negative error code on failure.
  */
 int mbedtls_aria_crypt_ecb( mbedtls_aria_context *ctx,
                             const unsigned char input[MBEDTLS_ARIA_BLOCKSIZE],
@@ -177,16 +192,21 @@
  *
  *
  * \param ctx      The ARIA context to use for encryption or decryption.
- * \param mode     The ARIA operation: #MBEDTLS_ARIA_ENCRYPT or
- *                 #MBEDTLS_ARIA_DECRYPT.
+ *                 This must be initialized and bound to a key.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_ARIA_ENCRYPT for encryption, or
+ *                 #MBEDTLS_ARIA_DECRYPT for decryption.
  * \param length   The length of the input data in Bytes. This must be a
  *                 multiple of the block size (16 Bytes).
  * \param iv       Initialization vector (updated after use).
- * \param input    The buffer holding the input data.
- * \param output   The buffer holding the output data.
+ *                 This must be a readable buffer of size 16 Bytes.
+ * \param input    The buffer holding the input data. This must
+ *                 be a readable buffer of length \p length Bytes.
+ * \param output   The buffer holding the output data. This must
+ *                 be a writable buffer of length \p length Bytes.
  *
- * \return         \c 0 on success, or #MBEDTLS_ERR_ARIA_INVALID_INPUT_LENGTH
- *                 on failure.
+ * \return         \c 0 on success.
+ * \return         A negative error code on failure.
  */
 int mbedtls_aria_crypt_cbc( mbedtls_aria_context *ctx,
                             int mode,
@@ -221,15 +241,22 @@
  *
  *
  * \param ctx      The ARIA context to use for encryption or decryption.
- * \param mode     The ARIA operation: #MBEDTLS_ARIA_ENCRYPT or
- *                 #MBEDTLS_ARIA_DECRYPT.
- * \param length   The length of the input data.
+ *                 This must be initialized and bound to a key.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_ARIA_ENCRYPT for encryption, or
+ *                 #MBEDTLS_ARIA_DECRYPT for decryption.
+ * \param length   The length of the input data \p input in Bytes.
  * \param iv_off   The offset in IV (updated after use).
+ *                 This must not be larger than 15.
  * \param iv       The initialization vector (updated after use).
- * \param input    The buffer holding the input data.
- * \param output   The buffer holding the output data.
+ *                 This must be a readable buffer of size 16 Bytes.
+ * \param input    The buffer holding the input data. This must
+ *                 be a readable buffer of length \p length Bytes.
+ * \param output   The buffer holding the output data. This must
+ *                 be a writable buffer of length \p length Bytes.
  *
  * \return         \c 0 on success.
+ * \return         A negative error code on failure.
  */
 int mbedtls_aria_crypt_cfb128( mbedtls_aria_context *ctx,
                                int mode,
@@ -299,17 +326,24 @@
  *             securely discarded as soon as it's no longer needed.
  *
  * \param ctx              The ARIA context to use for encryption or decryption.
- * \param length           The length of the input data.
- * \param nc_off           The offset in the current \p stream_block, for
- *                         resuming within the current cipher stream. The
- *                         offset pointer should be 0 at the start of a stream.
- * \param nonce_counter    The 128-bit nonce and counter.
- * \param stream_block     The saved stream block for resuming. This is
- *                         overwritten by the function.
- * \param input            The buffer holding the input data.
- * \param output           The buffer holding the output data.
+ *                         This must be initialized and bound to a key.
+ * \param length           The length of the input data \p input in Bytes.
+ * \param nc_off           The offset in Bytes in the current \p stream_block,
+ *                         for resuming within the current cipher stream. The
+ *                         offset pointer should be \c 0 at the start of a
+ *                         stream. This must not be larger than \c 15 Bytes.
+ * \param nonce_counter    The 128-bit nonce and counter. This must point to
+ *                         a read/write buffer of length \c 16 bytes.
+ * \param stream_block     The saved stream block for resuming. This must
+ *                         point to a read/write buffer of length \c 16 bytes.
+ *                         This is overwritten by the function.
+ * \param input            The buffer holding the input data. This must
+ *                         be a readable buffer of length \p length Bytes.
+ * \param output           The buffer holding the output data. This must
+ *                         be a writable buffer of length \p length Bytes.
  *
- * \return     \c 0 on success.
+ * \return                 \c 0 on success.
+ * \return                 A negative error code on failure.
  */
 int mbedtls_aria_crypt_ctr( mbedtls_aria_context *ctx,
                             size_t length,