diff --git a/include/mbedtls/aria.h b/include/mbedtls/aria.h
index 54db1a637..bd99b9fb8 100644
--- a/include/mbedtls/aria.h
+++ b/include/mbedtls/aria.h
@@ -91,15 +91,16 @@ mbedtls_aria_context;
* It must be the first API called before using
* the context.
*
- * \param ctx The ARIA context to initialize. Must not be \c NULL.
+ * \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. May be \c NULL, in which
- * case this function is a no-op.
+ * \param ctx The ARIA context to clear. This may be \c NULL, in which
+ * case this function is a no-op. If it is not \c NULL,
+ * it must point to an initialized ARIA context.
*/
void mbedtls_aria_free( mbedtls_aria_context *ctx );
@@ -107,10 +108,10 @@ void mbedtls_aria_free( mbedtls_aria_context *ctx );
* \brief This function sets the encryption key.
*
* \param ctx The ARIA context to which the key should be bound.
- * Must be initialized.
- * \param key The encryption key. Must be a readable buffer
- * of size \p keybits bits.
- * \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:
* - 128 bits
* - 192 bits
* - 256 bits
@@ -126,9 +127,9 @@ int mbedtls_aria_setkey_enc( mbedtls_aria_context *ctx,
* \brief This function sets the decryption key.
*
* \param ctx The ARIA context to which the key should be bound.
- * Must be initialized.
- * \param key The decryption key. Must be a readable buffer
- * of size \p keybits bits.
+ * 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:
* - 128 bits
* - 192 bits
@@ -154,7 +155,7 @@ int mbedtls_aria_setkey_dec( mbedtls_aria_context *ctx,
* call to this API with the same context.
*
* \param ctx The ARIA context to use for encryption or decryption.
- * Must be initialized.
+ * 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.
@@ -191,17 +192,18 @@ int mbedtls_aria_crypt_ecb( mbedtls_aria_context *ctx,
*
*
* \param ctx The ARIA context to use for encryption or decryption.
- * Must be initialized.
- * \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).
- * Must be a readable buffer of size 16 Bytes.
+ * This must be a readable buffer of size 16 Bytes.
* \param input The buffer holding the input data.
- * May be \c NULL if `length == 0`.
+ * This may be \c NULL if `length == 0`.
* \param output The buffer holding the output data.
- * May be \c NULL if `length == 0`.
+ * This may be \c NULL if `length == 0`.
*
* \return \c 0 on success.
* \return A negative error code on failure.
@@ -239,18 +241,19 @@ int mbedtls_aria_crypt_cbc( mbedtls_aria_context *ctx,
*
*
* \param ctx The ARIA context to use for encryption or decryption.
- * Must be initialized.
- * \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).
- * Must not be larger than 15.
+ * This must not be larger than 15.
* \param iv The initialization vector (updated after use).
- * Must be a readable buffer of size 16 Bytes.
+ * This must be a readable buffer of size 16 Bytes.
* \param input The buffer holding the input data.
- * May be \c NULL if `length == 0`.
+ * This may be \c NULL if `length == 0`.
* \param output The buffer holding the output data.
- * May be \c NULL if `length == 0`.
+ * This may be \c NULL if `length == 0`.
*
* \return \c 0 on success.
* \return A negative error code on failure.
@@ -323,21 +326,21 @@ int mbedtls_aria_crypt_cfb128( mbedtls_aria_context *ctx,
* securely discarded as soon as it's no longer needed.
*
* \param ctx The ARIA context to use for encryption or decryption.
- * Must be initialized.
- * \param length The length of the input 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 the current \p stream_block, for
* resuming within the current cipher stream. The
* offset pointer should be 0 at the start of a stream.
- * Must not be larger than 15.
- * \param nonce_counter The 128-bit nonce and counter. Must point to
- * an RW-buffer of length 16 bytes.
- * \param stream_block The saved stream block for resuming. Must point to
+ * This must not be larger than 15.
+ * \param nonce_counter The 128-bit nonce and counter. This must point to
* an RW-buffer of length 16 bytes.
+ * \param stream_block The saved stream block for resuming. This must
+ * point to an RW-buffer of length 16 bytes.
* This is overwritten by the function.
* \param input The buffer holding the input data.
- * May be \c NULL if `length == 0`.
+ * This may be \c NULL if `length == 0`.
* \param output The buffer holding the output data.
- * May be \c NULL if `length == 0`.
+ * This may be \c NULL if `length == 0`.
*
* \return \c 0 on success.
* \return A negative error code on failure.