Minor improvements to ChaCha20/Poly1305/ChaChaPoly documentation
diff --git a/include/mbedtls/chachapoly.h b/include/mbedtls/chachapoly.h
index 80d20e5..49e615d 100644
--- a/include/mbedtls/chachapoly.h
+++ b/include/mbedtls/chachapoly.h
@@ -123,7 +123,7 @@
* \brief This function releases and clears the specified
* ChaCha20-Poly1305 context.
*
- * \param ctx The ChachaPoly context to clear. May be \c NULL, in which
+ * \param ctx The ChachaPoly context to clear. This may be \c NULL, in which
* case this function is a no-op.
*/
void mbedtls_chachapoly_free( mbedtls_chachapoly_context *ctx );
@@ -133,8 +133,8 @@
* symmetric encryption key.
*
* \param ctx The ChaCha20-Poly1305 context to which the key should be
- * bound. Must be initialized.
- * \param key The 256-bit (32 bytes) key.
+ * bound. This must be initialized.
+ * \param key The \c 256 Bit (\c 32 Bytes) key.
*
* \return \c 0 on success.
* \return A negative error code on failure.
@@ -157,8 +157,10 @@
* \warning Decryption with the piecewise API is discouraged, see the
* warning on \c mbedtls_chachapoly_init().
*
- * \param ctx The ChaCha20-Poly1305 context. Must be initialized.
- * \param nonce The nonce/IV to use for the message. Must be 12 bytes.
+ * \param ctx The ChaCha20-Poly1305 context. This must be initialized
+ * and bound to a key.
+ * \param nonce The nonce/IV to use for the message.
+ * This must be a redable buffer of length \c 12 Bytes.
* \param mode The operation to perform: #MBEDTLS_CHACHAPOLY_ENCRYPT or
* #MBEDTLS_CHACHAPOLY_DECRYPT (discouraged, see warning).
*
@@ -194,11 +196,12 @@
* \warning Decryption with the piecewise API is discouraged, see the
* warning on \c mbedtls_chachapoly_init().
*
- * \param ctx The ChaCha20-Poly1305 context to use.
- * \param aad_len The length (in bytes) of the AAD. The length has no
+ * \param ctx The ChaCha20-Poly1305 context. This must be initialized
+ * and bound to a key.
+ * \param aad_len The length in Bytes of the AAD. The length has no
* restrictions.
* \param aad Buffer containing the AAD.
- * This pointer can be NULL if aad_len == 0.
+ * This pointer can be \c NULL if `aad_len == 0`.
*
* \return \c 0 on success.
* \return #MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA
@@ -228,12 +231,12 @@
* \warning Decryption with the piecewise API is discouraged, see the
* warning on \c mbedtls_chachapoly_init().
*
- * \param ctx The ChaCha20-Poly1305 context to use. Must be initialized.
+ * \param ctx The ChaCha20-Poly1305 context to use. This must be initialized.
* \param len The length (in bytes) of the data to encrypt or decrypt.
* \param input The buffer containing the data to encrypt or decrypt.
* This pointer can be \c NULL if `len == 0`.
* \param output The buffer to where the encrypted or decrypted data is
- * written. Must be able to hold \p len bytes.
+ * written. This must be able to hold \p len bytes.
* This pointer can be \c NULL if `len == 0`.
*
* \return \c 0 on success.
@@ -251,7 +254,7 @@
* \brief This function finished the ChaCha20-Poly1305 operation and
* generates the MAC (authentication tag).
*
- * \param ctx The ChaCha20-Poly1305 context to use. Must be initialized.
+ * \param ctx The ChaCha20-Poly1305 context to use. This must be initialized.
* \param mac The buffer to where the 128-bit (16 bytes) MAC is written.
*
* \warning Decryption with the piecewise API is discouraged, see the
@@ -279,17 +282,18 @@
* and key.
*
* \param ctx The ChaCha20-Poly1305 context to use (holds the key).
- * Must be initialized.
+ * This must be initialized.
* \param length The length (in bytes) of the data to encrypt or decrypt.
* \param nonce The 96-bit (12 bytes) nonce/IV to use.
- * \param aad The buffer containing the additional authenticated data (AAD).
- * This pointer can be \c NULL if `aad_len == 0`.
+ * \param aad The buffer containing the additional authenticated
+ * data (AAD). This pointer can be \c NULL if `aad_len == 0`.
* \param aad_len The length (in bytes) of the AAD data to process.
* \param input The buffer containing the data to encrypt or decrypt.
* This pointer can be \c NULL if `ilen == 0`.
- * \param output The buffer to where the encrypted or decrypted data is written.
- * This pointer can be \c NULL if `ilen == 0`.
- * \param tag The buffer to where the computed 128-bit (16 bytes) MAC is written.
+ * \param output The buffer to where the encrypted or decrypted data
+ * is written. This pointer can be \c NULL if `ilen == 0`.
+ * \param tag The buffer to where the computed 128-bit (16 bytes) MAC
+ * is written. This must not be \c NULL.
*
* \return \c 0 on success.
* \return A negative error code on failure.
@@ -311,16 +315,17 @@
* \c mbedtls_chachapoly_setkey().
*
* \param ctx The ChaCha20-Poly1305 context to use (holds the key).
- * \param length The length (in bytes) of the data to decrypt.
- * \param nonce The 96-bit (12 bytes) nonce/IV to use.
+ * \param length The length (in Bytes) of the data to decrypt.
+ * \param nonce The \c 96 Bit (\c 12 bytes) nonce/IV to use.
* \param aad The buffer containing the additional authenticated data (AAD).
- * This pointer can be NULL if aad_len == 0.
+ * This pointer can be \c NULL if `aad_len == 0`.
* \param aad_len The length (in bytes) of the AAD data to process.
* \param tag The buffer holding the authentication tag.
+ * This must be a readable buffer of length \c 16 Bytes.
* \param input The buffer containing the data to decrypt.
- * This pointer can be NULL if ilen == 0.
+ * This pointer can be \c NULL if `ilen == 0`.
* \param output The buffer to where the decrypted data is written.
- * This pointer can be NULL if ilen == 0.
+ * This pointer can be \c NULL if `ilen == 0`.
*
* \return \c 0 on success.
* \return #MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED