Fix a/an typos in doxygen and other comments

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>

include/psa/crypto.h

@@ -545,7 +545,7 @@ psa_status_t psa_copy_key(mbedtls_svc_key_id_t source_key,
  * \retval #PSA_ERROR_INVALID_HANDLE
  *         \p key is not a valid identifier nor \c 0.
  * \retval #PSA_ERROR_COMMUNICATION_FAILURE
- *         There was an failure in communication with the cryptoprocessor.
+ *         There was a failure in communication with the cryptoprocessor.
  *         The key material may still be present in the cryptoprocessor.
  * \retval #PSA_ERROR_DATA_INVALID
  *         This error is typically a result of either storage corruption on a

include/psa/crypto_compat.h

@@ -44,7 +44,7 @@ typedef mbedtls_svc_key_id_t psa_key_handle_t;
 
 #define PSA_KEY_HANDLE_INIT MBEDTLS_SVC_KEY_ID_INIT
 
-/** Check whether an handle is null.
+/** Check whether a handle is null.
  *
  * \param handle  Handle
  *

include/psa/crypto_extra.h

@@ -359,7 +359,7 @@ psa_status_t mbedtls_psa_inject_entropy(const uint8_t *seed,
  */
 #define PSA_KEY_TYPE_DSA_KEY_PAIR                    ((psa_key_type_t)0x7002)
 
-/** Whether a key type is an DSA key (pair or public-only). */
+/** Whether a key type is a DSA key (pair or public-only). */
 #define PSA_KEY_TYPE_IS_DSA(type)                                       \
     (PSA_KEY_TYPE_PUBLIC_KEY_OF_KEY_PAIR(type) == PSA_KEY_TYPE_DSA_PUBLIC_KEY)
 
@@ -1287,7 +1287,7 @@ static void psa_pake_cs_set_hash( psa_pake_cipher_suite_t *cipher_suite,
  * Implementation details can change in future versions without notice. */
 typedef struct psa_pake_operation_s psa_pake_operation_t;
 
-/** Return an initial value for an PAKE operation object.
+/** Return an initial value for a PAKE operation object.
  */
 static psa_pake_operation_t psa_pake_operation_init( void );
 

include/psa/crypto_platform.h

@@ -57,8 +57,8 @@
  *
  * The function psa_its_identifier_of_slot() in psa_crypto_storage.c that
  * translates a key identifier to a key storage file name assumes that
- * mbedtls_key_owner_id_t is an 32 bits integer. This function thus needs
- * reworking if mbedtls_key_owner_id_t is not defined as a 32 bits integer
+ * mbedtls_key_owner_id_t is a 32-bit integer. This function thus needs
+ * reworking if mbedtls_key_owner_id_t is not defined as a 32-bit integer
  * here anymore.
  */
 typedef int32_t mbedtls_key_owner_id_t;

include/psa/crypto_se_driver.h

@@ -395,7 +395,7 @@ typedef psa_status_t (*psa_drv_se_cipher_setup_t)(psa_drv_se_context_t *drv_cont
                                                   psa_encrypt_or_decrypt_t direction);
 
 /** \brief A function that sets the initialization vector (if
- * necessary) for an secure element cipher operation
+ * necessary) for a secure element cipher operation
  *
  * Rationale: The `psa_se_cipher_*` operation in the PSA Cryptographic API has
  * two IV functions: one to set the IV, and one to generate it internally. The

include/psa/crypto_types.h

@@ -105,7 +105,7 @@ typedef uint8_t psa_ecc_family_t;
  * Values of this type are generally constructed by macros called
  * `PSA_DH_FAMILY_xxx`.
  *
- * The group identifier is required to create an Diffie-Hellman key using the
+ * The group identifier is required to create a Diffie-Hellman key using the
  * PSA_KEY_TYPE_DH_KEY_PAIR() or PSA_KEY_TYPE_DH_PUBLIC_KEY()
  * macros.
  *

include/psa/crypto_values.h

@@ -1265,7 +1265,7 @@
  */
 #define PSA_ALG_CHACHA20_POLY1305               ((psa_algorithm_t)0x05100500)
 
-/* In the encoding of a AEAD algorithm, the bits corresponding to
+/* In the encoding of an AEAD algorithm, the bits corresponding to
  * PSA_ALG_AEAD_TAG_LENGTH_MASK encode the length of the AEAD tag.
  * The constants for default lengths follow this encoding.
  */