The GCM module now supports arbitrary chunked input in the multipart interface. This changes the interface for applications using the GCM module directly for multipart operations. Applications using one-shot GCM or using GCM via the
psa_aead_xxx interfaces do not require any changes.
mbedtls_gcm_starts()now only sets the mode and the nonce (IV). Call the new function
mbedtls_gcm_update_ad()to pass the associated data.
mbedtls_gcm_update()now takes an extra parameter to indicate the actual output length. In Mbed TLS 2.x, applications had to pass inputs consisting of whole 16-byte blocks except for the last block (this limitation has been lifted). In this case:
mbedtls_gcm_finish()instead of returning it in the last call to
mbedtls_gcm_finish()now takes an extra output buffer for the last partial block. This is needed for alternative implementations that can only process a whole block at a time.