Off-chip Nor Flash bus interface hardware encryption device

Abstract

The invention relates to an off-chip Nor Flash bus interface hardware encryption device which comprises an EMI (external memory interface), a data reading decryption passage, a data reading bypass passage, a data writing passage and an AES (advanced encryption standard) encryption engine, wherein the EMI is used for CPU (central processing unit) extensible external memories, the three passages connects the EMI with external Nor Flash memories, the AES encryption engine is connected between a CPU and the data reading decryption passage and used for plaintext data encryption, and the data reading decryption passage comprises an address analyzing unit, an address comparing unit, an indication control unit, a cipher text buffer unit, an AES decryption engine, a plaintext buffer unit and a secret key storage unit. Hardware-software combination is used to provide data encryption for off-chip Nor Flash memories. The device supports a bypass function, data can be written into off-chip Nor Flash memories in plaintext and read in plaintext, so that data storage flexibility is achieved. By the device which is flexible in extensibility, easy to design, high in reliability and safety and the like, Nor Flash bus interface encryption is achieved.

Description

technical field [0001] The invention relates to the fields of computer science, information security and embedded terminals, in particular to the field of off-chip Nor Flash memory bus interface encryption technology. Background technique [0002] Due to its small size, low power consumption, inherent non-volatility, reliability and stability, and long data storage time, Flash memory has the characteristics of up to 100,000 times of erasing and writing, and the data update speed is much faster than that of EEPROM. It can also save data and is widely used in embedded products to save some important configuration information; in addition, as a kind of Flash memory, Nor Flash has the characteristics of random reading data and fast reading speed; The application supports on-chip operation, and the program can run directly in FLASH without importing other data storage devices; therefore, many embedded products and their application systems use Nor Flash as the program and data st...

AI Technical Summary

Problems solved by technology

[0003] However, because the timing logic of the Nor Flash memory interface is relatively simple, only the address bus, data bus and control bus; unscrupulous competitors can easily copy other people's products or Deciphering the data on the product chip forms unequal competition, which not only infringes on the rights and interests of competitors, but also seriously harms the interests of end customers; therefore, some Nor Flash manufacturers add security protection functions to Nor Flash chips to protect information security; for example, Micro companies adopt Krypto? Security technology, this technology can strengthen the system-level protection mechanism through read, write and erase protection schemes to protect the data information security on the Nor Flash chip; however, during the system work, tools such as logic analyzers can still Monitor the bus signal to achieve the purpose of cracking the on-chip data

[0004] Currently, a software solution is commonly used for Nor Flash data protection, first encrypting the data and then burning it to the Nor Flash; when using data, read the encrypted data on the system and use software to decrypt it; this implementation has the following defects : First, the data must be encrypted first and then programmed, which lacks flexibility; second, the same key is generally used to encrypt data, that is, the key is single. If different keys are to be supported for each product, the production and software output will be complicated; Third, one key exists and is used when data is encrypted, and the other is solidified in software, both of which have security risks, that is, there is a risk of being easily stolen by others

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