參數(shù)資料
型號: MQ80C32E-30/883
廠商: TEMIC SEMICONDUCTORS
元件分類: 微控制器/微處理器
英文描述: 8-BIT, 30 MHz, MICROCONTROLLER, CQFP44
文件頁數(shù): 37/198頁
文件大?。?/td> 4822K
代理商: MQ80C32E-30/883
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁當(dāng)前第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁第65頁第66頁第67頁第68頁第69頁第70頁第71頁第72頁第73頁第74頁第75頁第76頁第77頁第78頁第79頁第80頁第81頁第82頁第83頁第84頁第85頁第86頁第87頁第88頁第89頁第90頁第91頁第92頁第93頁第94頁第95頁第96頁第97頁第98頁第99頁第100頁第101頁第102頁第103頁第104頁第105頁第106頁第107頁第108頁第109頁第110頁第111頁第112頁第113頁第114頁第115頁第116頁第117頁第118頁第119頁第120頁第121頁第122頁第123頁第124頁第125頁第126頁第127頁第128頁第129頁第130頁第131頁第132頁第133頁第134頁第135頁第136頁第137頁第138頁第139頁第140頁第141頁第142頁第143頁第144頁第145頁第146頁第147頁第148頁第149頁第150頁第151頁第152頁第153頁第154頁第155頁第156頁第157頁第158頁第159頁第160頁第161頁第162頁第163頁第164頁第165頁第166頁第167頁第168頁第169頁第170頁第171頁第172頁第173頁第174頁第175頁第176頁第177頁第178頁第179頁第180頁第181頁第182頁第183頁第184頁第185頁第186頁第187頁第188頁第189頁第190頁第191頁第192頁第193頁第194頁第195頁第196頁第197頁第198頁
131
8111C–MCU Wireless–09/09
AT86RF231
When decrypting, due to the nature of AES algorithm, the initial key to be used is not the same
as the one used for encryption, but rather the last round key instead. This last round key is the
content of the key address space stored after running one full encryption cycle, and must be
saved for decryption. If the decryption key has not been saved, it has to be recomputed by first
running a dummy encryption (of an arbitrary plaintext) using the original encryption key, then
fetching the resulting round key from the key memory, and writing it back into the key memory as
the decryption key.
ECB decryption is not used by either IEEE 802.15.4 or ZigBee frame security. Both of these
standards do not directly encrypt the payload, but rather a nonce instead, and protect the pay-
load by applying an XOR operation between the resulting (AES-) cipher text and the original
payload. As the nonce is the same for encryption and decryption only ECB encryption is
required. Decryption is performed by XORing the received cipher text with its own encryption
result respectively, which results in the original plaintext payload upon success.
11.1.4.2
Cipher Block Chaining (CBC)
In CBC mode, the result of a previous AES operation is XORed with the new incoming vector,
forming the new plaintext to encrypt, see Figure 11-4 on page 131. This mode is used for the
computation of a cryptographic checksum (message integrity code, MIC).
Figure 11-4. CBC Mode - Encryption
After preparing the AES key, and defining the AES operation direction using SRAM register bit
AES_DIR, the data has to be provided to the AES engine and the CBC operation can be started.
The first CBC run has to be configured as ECB to process the initial data (plaintext XORed with
an initialization vector provided by the microcontroller). All succeeding AES runs are to be con-
figured as CBC by setting register bits AES_MODE = 0x2 (register 0x83, AES_CTRL). Register
bit AES_DIR (register 0x83, AES_CTRL) must be set to AES_DIR = 0 to enable AES encryption.
The data to be processed has to be transferred to the SRAM starting with address 0x84 to 0x93
(register AES_STA T E). Setting register bit AES_REQUEST = 1 (register 0x94,
starts the first encryption within one SRAM access. This causes the next 128 bits of plaintext
data to be XORed with the previous cipher text data, see Figure 11-4 on page 131.
According to IEEE 802.15.4 the input for the very first CBC operation has to be prepared by a
XORing a plaintext with an initialization vector (IV). The value of the initialization vector is 0.
However, for non-compliant usage any other initialization vector can be used. This operation has
to be prepared by the microcontroller.
Block Cipher
Encryption
Key
Ciphertext
Block Cipher
Encryption
Plaintext
Ciphertext
Plaintext
Initialization Vector (IV)
Encryption
Key
ECB
mode
CBC
mode
相關(guān)PDF資料
PDF描述
MR80C52CXXX-16/883R 8-BIT, MROM, 16 MHz, MICROCONTROLLER, CQCC44
MR80C52TXXX-16SB 8-BIT, MROM, 16 MHz, MICROCONTROLLER, CQCC44
MD83C154TXXX-L16P883D 8-BIT, MROM, 16 MHz, MICROCONTROLLER, CDIP40
MD83C154XXX-L16P883D 8-BIT, MROM, 16 MHz, MICROCONTROLLER, CDIP40
MQ80C32E-16SB 8-BIT, 16 MHz, MICROCONTROLLER, CQFP44
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MQ82370-20 制造商:Rochester Electronics LLC 功能描述:- Bulk
MQ8238020 制造商:Intel 功能描述:CONTROLLER: OTHER
MQ82380-20 制造商:Rochester Electronics LLC 功能描述:- Bulk
MQ82380-20/R 制造商:Rochester Electronics LLC 功能描述:
MQ82592 制造商:Rochester Electronics LLC 功能描述:- Bulk