Update documentation for internal implementation
Signed-off-by: Paul Elliott <paul.elliott@arm.com>
This commit is contained in:
Paul Elliott
parent
b06e1c0d68
commit
4148a68169
@ -155,39 +155,14 @@ psa_status_t mbedtls_psa_aead_decrypt(
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* aead_encrypt_setup entry point as defined in the PSA driver interface
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* specification for transparent drivers.
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*
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* The sequence of operations to encrypt a message with authentication
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* is as follows:
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* -# Allocate an operation object which will be passed to all the functions
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* listed here.
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* -# Initialize the operation object with one of the methods described in the
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* documentation for #mbedtls_psa_aead_operation_t, e.g.
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* #MBEDTLS_PSA_AEAD_OPERATION_INIT.
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* -# Call mbedtls_psa_aead_encrypt_setup() to specify the algorithm and key.
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* -# If needed, call mbedtls_psa_aead_set_lengths() to specify the length of
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* the inputs to the subsequent calls to mbedtls_psa_aead_update_ad() and
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* mbedtls_psa_aead_update(). See the documentation of
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* mbedtls_psa_aead_set_lengths() for details.
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* -# Call either psa_aead_generate_nonce() or
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* mbedtls_psa_aead_set_nonce() to generate or set the nonce. You should use
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* psa_aead_generate_nonce() unless the protocol you are implementing
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* requires a specific nonce value.
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* -# Call mbedtls_psa_aead_update_ad() zero, one or more times, passing
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* a fragment of the non-encrypted additional authenticated data each time.
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* -# Call mbedtls_psa_aead_update() zero, one or more times, passing a fragment
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* of the message to encrypt each time.
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* -# Call mbedtls_psa_aead_finish().
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*
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* If an error occurs at any step after a call to
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* mbedtls_psa_aead_encrypt_setup(), the operation will need to be reset by a
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* call to mbedtls_psa_aead_abort(). The application may call
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* mbedtls_psa_aead_encrypt_setup(), the operation is reset by the PSA core by a
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* call to mbedtls_psa_aead_abort(). The PSA core may call
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* mbedtls_psa_aead_abort() at any time after the operation has been
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* initialized.
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*
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* After a successful call to mbedtls_psa_aead_encrypt_setup(), the application
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* must eventually terminate the operation. The following events terminate an
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* operation:
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* - A successful call to mbedtls_psa_aead_finish().
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* - A call to mbedtls_psa_aead_abort().
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* After a successful call to mbedtls_psa_aead_encrypt_setup(), the PSA core
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* eventually terminates the operation by calling mbedtls_psa_aead_abort().
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*
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* \param[in,out] operation The operation object to set up. It must have
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* been initialized as per the documentation for
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@ -236,36 +211,14 @@ psa_status_t mbedtls_psa_aead_encrypt_setup(mbedtls_psa_aead_operation_t
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* aead_decrypt_setup entry point as defined in the PSA driver interface
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* specification for transparent drivers.
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*
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* The sequence of operations to decrypt a message with authentication
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* is as follows:
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* -# Allocate an operation object which will be passed to all the functions
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* listed here.
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* -# Initialize the operation object with one of the methods described in the
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* documentation for #mbedtls_psa_aead_operation_t, e.g.
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* #PSA_AEAD_OPERATION_INIT.
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* -# Call mbedtls_psa_aead_decrypt_setup() to specify the algorithm and key.
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* -# If needed, call mbedtls_psa_aead_set_lengths() to specify the length of
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* the inputs to the subsequent calls to mbedtls_psa_aead_update_ad() and
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* mbedtls_psa_aead_update(). See the documentation of
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* mbedtls_psa_aead_set_lengths() for details.
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* -# Call mbedtls_psa_aead_set_nonce() with the nonce for the decryption.
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* -# Call mbedtls_psa_aead_update_ad() zero, one or more times, passing a
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* fragment of the non-encrypted additional authenticated data each time.
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* -# Call mbedtls_psa_aead_update() zero, one or more times, passing a fragment
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* of the ciphertext to decrypt each time.
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* -# Call mbedtls_psa_aead_verify().
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*
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* If an error occurs at any step after a call to
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* mbedtls_psa_aead_decrypt_setup(), the operation will need to be reset by a
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* call to mbedtls_psa_aead_abort(). The application may call
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* mbedtls_psa_aead_decrypt_setup(), the PSA core resets the operation by a
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* call to mbedtls_psa_aead_abort(). The PSA core may call
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* mbedtls_psa_aead_abort() at any time after the operation has been
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* initialized.
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*
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* After a successful call to mbedtls_psa_aead_decrypt_setup(), the application
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* must eventually terminate the operation. The following events terminate an
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* operation:
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* - A successful call to mbedtls_psa_aead_verify().
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* - A call to mbedtls_psa_aead_abort().
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* After a successful call to mbedtls_psa_aead_decrypt_setup(), the PSA core
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* eventually terminates the operation by a call to mbedtls_psa_aead_abort().
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*
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* \param[in,out] operation The operation object to set up. It must have
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* been initialized as per the documentation for
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@ -309,23 +262,19 @@ psa_status_t mbedtls_psa_aead_decrypt_setup(mbedtls_psa_aead_operation_t
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/** Set the nonce for an authenticated encryption or decryption operation.
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*
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* \note The signature of this function is that of a PSA driver
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* psa_aead_set_nonce entry point. This function behaves as an
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* psa_aead_set_nonce entry point as defined in the PSA driver interface
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* specification for transparent drivers.
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* \note The signature of this function is that of a PSA driver aead_set_nonce
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* entry point. This function behaves as an aead_set_nonce entry point as
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* defined in the PSA driver interface specification for transparent
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* drivers.
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*
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* This function sets the nonce for the authenticated
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* encryption or decryption operation.
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*
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* The application must call mbedtls_psa_aead_encrypt_setup() or
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* The PSA core calls mbedtls_psa_aead_encrypt_setup() or
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* mbedtls_psa_aead_decrypt_setup() before calling this function.
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*
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* If this function returns an error status, the operation enters an error
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* state and must be aborted by calling mbedtls_psa_aead_abort().
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*
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* \note When encrypting, applications should use
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* mbedtls_psa_aead_generate_nonce() instead of this function, unless
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* implementing a protocol that requires a non-random IV.
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* If this function returns an error status, the PSA core calls
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* mbedtls_psa_aead_abort().
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*
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* \param[in,out] operation Active AEAD operation.
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* \param[in] nonce Buffer containing the nonce to use.
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@ -354,19 +303,18 @@ psa_status_t mbedtls_psa_aead_set_nonce(mbedtls_psa_aead_operation_t *operation,
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/** Declare the lengths of the message and additional data for AEAD.
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*
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* \note The signature of this function is that of a PSA driver
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* psa_aead_set_lengths entry point. This function behaves as an
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* psa_aead_set_lengths entry point as defined in the PSA driver interface
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* specification for transparent drivers.
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* \note The signature of this function is that of a PSA driver aead_set_lengths
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* entry point. This function behaves as an aead_set_lengths entry point
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* as defined in the PSA driver interface specification for transparent
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* drivers.
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*
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* The application must call this function before calling
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* mbedtls_psa_aead_update_ad() or mbedtls_psa_aead_update() if the algorithm
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* for the operation requires it. If the algorithm does not require it, calling
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* this function is optional, but if this function is called then the
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* implementation must enforce the lengths.
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* The PSA core calls this function before calling mbedtls_psa_aead_update_ad()
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* or mbedtls_psa_aead_update() if the algorithm for the operation requires it.
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* If the algorithm does not require it, calling this function is optional, but
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* if this function is called then the implementation must enforce the lengths.
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*
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* You may call this function before or after setting the nonce with
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* mbedtls_psa_aead_set_nonce() or psa_aead_generate_nonce().
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* The PSA core may call this function before or after setting the nonce with
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* mbedtls_psa_aead_set_nonce().
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*
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* - For #PSA_ALG_CCM, calling this function is required.
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* - For the other AEAD algorithms defined in this specification, calling
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@ -413,17 +361,17 @@ psa_status_t mbedtls_psa_aead_set_lengths(mbedtls_psa_aead_operation_t
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*
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* Additional data is authenticated, but not encrypted.
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*
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* You may call this function multiple times to pass successive fragments
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* of the additional data. You may not call this function after passing
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* data to encrypt or decrypt with mbedtls_psa_aead_update().
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* The PSA core can call this function multiple times to pass successive
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* fragments of the additional data. It will not call this function after
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* passing data to encrypt or decrypt with mbedtls_psa_aead_update().
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*
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* Before calling this function, you must:
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* Before calling this function, The PSA core will:
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* 1. Call either mbedtls_psa_aead_encrypt_setup() or
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* mbedtls_psa_aead_decrypt_setup(). 2. Set the nonce with
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* psa_aead_generate_nonce() or mbedtls_psa_aead_set_nonce().
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* mbedtls_psa_aead_decrypt_setup().
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* 2. Set the nonce with mbedtls_psa_aead_set_nonce().
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*
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* If this function returns an error status, the operation enters an error
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* state and must be aborted by calling mbedtls_psa_aead_abort().
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* If this function returns an error status, the PSA core will call
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* mbedtls_psa_aead_abort().
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*
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* \warning When decrypting, until mbedtls_psa_aead_verify() has returned
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* #PSA_SUCCESS, there is no guarantee that the input is valid.
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@ -433,8 +381,8 @@ psa_status_t mbedtls_psa_aead_set_lengths(mbedtls_psa_aead_operation_t
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* mbedtls_psa_aead_verify() returns an error status.
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*
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* \note For the time being #PSA_ALG_CCM and #PSA_ALG_GCM require the entire
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* additional data to be passed in in one go, i.e. only call
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* mbedtls_mbedtls_psa_aead_update_ad() once.
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* additional data to be passed in in one go, i.e.
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* mbedtls_mbedtls_psa_aead_update_ad() can only be called once.
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*
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* \param[in,out] operation Active AEAD operation.
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* \param[in] input Buffer containing the fragment of
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@ -471,31 +419,15 @@ psa_status_t mbedtls_psa_aead_update_ad(mbedtls_psa_aead_operation_t *operation,
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* point as defined in the PSA driver interface specification for
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* transparent drivers.
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*
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* Before calling this function, you must:
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* Before calling this function, the PSA core will:
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* 1. Call either mbedtls_psa_aead_encrypt_setup() or
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* mbedtls_psa_aead_decrypt_setup(). The choice of setup function determines
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* whether this function encrypts or decrypts its input.
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* 2. Set the nonce with psa_aead_generate_nonce() or
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* mbedtls_psa_aead_set_nonce(). 3. Call mbedtls_psa_aead_update_ad() to pass
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* all the additional data.
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* mbedtls_psa_aead_decrypt_setup(). The choice of setup function
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* determines whether this function encrypts or decrypts its input.
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* 2. Set the nonce with mbedtls_psa_aead_set_nonce().
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* 3. Call mbedtls_psa_aead_update_ad() to pass all the additional data.
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*
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* If this function returns an error status, the operation enters an error
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* state and must be aborted by calling mbedtls_psa_aead_abort().
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*
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* \warning When decrypting, until mbedtls_psa_aead_verify() has returned
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* #PSA_SUCCESS, there is no guarantee that the input is valid.
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* Therefore, until you have called mbedtls_psa_aead_verify() and it
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* has returned #PSA_SUCCESS:
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* - Do not use the output in any way other than storing it in a
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* confidential location. If you take any action that depends
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* on the tentative decrypted data, this action will need to be
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* undone if the input turns out not to be valid. Furthermore,
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* if an adversary can observe that this action took place
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* (for example through timing), they may be able to use this
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* fact as an oracle to decrypt any message encrypted with the
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* same key.
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* - In particular, do not copy the output anywhere but to a
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* memory or storage space that you have exclusive access to.
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* If this function returns an error status, the PSA core will call
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* mbedtls_psa_aead_abort().
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*
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* This function does not require the input to be aligned to any
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* particular block boundary. If the implementation can only process
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@ -506,8 +438,8 @@ psa_status_t mbedtls_psa_aead_update_ad(mbedtls_psa_aead_operation_t *operation,
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* can be delayed in this way is bounded by #PSA_AEAD_UPDATE_OUTPUT_SIZE.
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*
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* \note For the time being #PSA_ALG_CCM and #PSA_ALG_GCM require the entire
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* data to be passed in in one go, i.e. only call
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* mbedtls_mbedtls_psa_aead_update() once.
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* data to be passed in in one go, i.e. mbedtls_mbedtls_psa_aead_update()
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* can only be called once.
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*
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* \param[in,out] operation Active AEAD operation.
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* \param[in] input Buffer containing the message fragment to
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@ -563,7 +495,8 @@ psa_status_t mbedtls_psa_aead_update(mbedtls_psa_aead_operation_t *operation,
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* point as defined in the PSA driver interface specification for
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* transparent drivers.
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*
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* The operation must have been set up with mbedtls_psa_aead_encrypt_setup().
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* The operation must have been set up by the PSA core with
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* mbedtls_psa_aead_encrypt_setup().
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*
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* This function finishes the authentication of the additional data
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* formed by concatenating the inputs passed to preceding calls to
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@ -572,14 +505,11 @@ psa_status_t mbedtls_psa_aead_update(mbedtls_psa_aead_operation_t *operation,
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*
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* This function has two output buffers:
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* - \p ciphertext contains trailing ciphertext that was buffered from
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* preceding calls to mbedtls_psa_aead_update().
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* - \p tag contains the authentication tag. Its length is always
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* #PSA_AEAD_TAG_LENGTH(\c alg) where \c alg is the AEAD algorithm
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* that the operation performs.
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* preceding calls to psa_aead_update().
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* - \p tag contains the authentication tag.
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*
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* When this function returns successfuly, the operation becomes inactive.
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* If this function returns an error status, the operation enters an error
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* state and must be aborted by calling mbedtls_psa_aead_abort().
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* Whether or not this function returns successfuly, the PSA core subsequently
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* calls mbedtls_psa_aead_abort() to deactivate the operation.
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*
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* \param[in,out] operation Active AEAD operation.
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* \param[out] ciphertext Buffer where the last part of the ciphertext
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@ -594,9 +524,17 @@ psa_status_t mbedtls_psa_aead_update(mbedtls_psa_aead_operation_t *operation,
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* \param[out] tag Buffer where the authentication tag is
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* to be written.
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* \param tag_size Size of the \p tag buffer in bytes.
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* This must be at least
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* #PSA_AEAD_TAG_LENGTH(\c alg) where \c alg is
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* the algorithm that is being calculated.
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* This must be appropriate for the selected
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* algorithm and key:
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* - The exact tag size is #PSA_AEAD_TAG_LENGTH(\c
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* key_type, \c key_bits, \c alg) where
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* \c key_type and \c key_bits are the type and
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* bit-size of the key, and \c alg is the
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* algorithm that were used in the call to
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* psa_aead_encrypt_setup().
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* - #PSA_AEAD_TAG_MAX_SIZE evaluates to the
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* maximum tag size of any supported AEAD
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* algorithm.
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* \param[out] tag_length On success, the number of bytes
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* that make up the returned tag.
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*
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@ -610,8 +548,9 @@ psa_status_t mbedtls_psa_aead_update(mbedtls_psa_aead_operation_t *operation,
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* You can determine a sufficient buffer size for \p ciphertext by
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* calling #PSA_AEAD_FINISH_OUTPUT_SIZE(\c alg)
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* where \c alg is the algorithm that is being calculated.
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* You can determine a sufficient buffer size for \p tag by
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* calling #PSA_AEAD_TAG_LENGTH(\c alg).
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* #PSA_AEAD_TAG_LENGTH(\c key_type, \c key_bits, \c alg) or
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* #PSA_AEAD_TAG_MAX_SIZE can be used to determine the required \p tag
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* buffer size.
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* \retval #PSA_ERROR_INVALID_ARGUMENT
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* The total length of input to psa_aead_update_ad() so far is
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* less than the additional data length that was previously
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@ -645,7 +584,8 @@ psa_status_t mbedtls_psa_aead_finish(mbedtls_psa_aead_operation_t *operation,
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* point as defined in the PSA driver interface specification for
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* transparent drivers.
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*
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* The operation must have been set up with mbedtls_psa_aead_decrypt_setup().
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* The operation must have been set up by the PSA core with
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* mbedtls_psa_aead_decrypt_setup().
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*
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* This function finishes the authenticated decryption of the message
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* components:
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@ -660,9 +600,8 @@ psa_status_t mbedtls_psa_aead_finish(mbedtls_psa_aead_operation_t *operation,
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* plaintext and reports success. If the authentication tag is not correct,
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* this function returns #PSA_ERROR_INVALID_SIGNATURE.
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*
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* When this function returns successfuly, the operation becomes inactive.
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* If this function returns an error status, the operation enters an error
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* state and must be aborted by calling mbedtls_psa_aead_abort().
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* Whether or not this function returns successfully, the PSA core subsequently
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* calls mbedtls_psa_aead_abort() to deactivate the operation.
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*
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* \note Implementations shall make the best effort to ensure that the
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* comparison between the actual tag and the expected tag is performed
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@ -731,10 +670,10 @@ psa_status_t mbedtls_psa_aead_verify(mbedtls_psa_aead_operation_t *operation,
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*
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* Aborting an operation frees all associated resources except for the
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* \p operation structure itself. Once aborted, the operation object
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* can be reused for another operation by calling
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* can be reused for another operation by the PSA core by it calling
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* mbedtls_psa_aead_encrypt_setup() or mbedtls_psa_aead_decrypt_setup() again.
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*
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* You may call this function any time after the operation object has
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* The PSA core may call this function any time after the operation object has
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* been initialized as described in #mbedtls_psa_aead_operation_t.
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*
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* In particular, calling mbedtls_psa_aead_abort() after the operation has been
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