Maxim Integrated MAX32600, Руководство пользователя

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MAX32600 User’s Guide Introduction 2.8 Security Features
storage using an AES master key, then once a tamper response occurs and this master key has been deleted, the sensitive information will not be recoverable by an
attacker at that point; even if the ciphertext version of the information can be recovered in some way, the key that was used to encrypt that data no longer exists.
Another potential use of this key would be to encrypt larger keys that might be stored in long-term, nonvolatile storage on the device (such as a public key, private
key, or certificate, which might be stored in the main program flash). By encrypting the larger keys with the AES master key, they may safely be stored in a nonsecure
location such as the main SRAM or program flash memory; if a tamper response occurs, the AES key will be wiped, effectively destroying the other encrypted keys
or data as well since the encrypted information is now useless.
The Secure Key Storage area (which has a capacity of four 32-bit registers or 128 bits total) does not have to be used for an AES key, however; it can be used for
any type of secure data that must be immediately erased in the event of a tamper response.
2.8.4 Modular Arithmetic Accelerator (MAA)
The MAA cryptographic module is considered to be another component of the TPU. It allows firmware to perform 512-bit large number modular arithmetic operations
which can be used in turn to implement cryptographic algorithms such as RSA. The RSA set of cryptographic operations can be used for public/private cryptography
operations.
The MAA operates from a dedicated internal register file memory which is used to store keys, input and output parameters, and for scratch working space. The MAA
does not use the general purpose system SRAM to store data.
2.8.5 CRC Hardware Block with CRC16 and CRC32
A CRC hardware module is included to provide fast calculations and integrity checking of application software and data. The CRC module supports both CRC-16-
−
CCITT and CRC-32 polynomial modes. The CRC-16 operation completes in two clock cycles, while the CRC-32 operation requires four cycles.
Additional features of the CRC module include:
• Programmable start seed
• Programmable start address
• Programmable length
• Direct load or PMU-based memory load support
2.8.6 Code Scrambling
All application code and data loaded into the main program flash memory is scrambled in both content and location by hardware before it is stored in the flash. When
data is retrieved from the flash, it is descrambled before arriving at the program cache (for instruction fetches) or the main data bus (for data fetches). Both the
scrambling and descrambling operations are transparent to the end user.
Rev.1.3 April 2015 Maxim Integrated Page 22