ATAES132A ECB mode

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#1
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Hi to all,

 

I'm Using an ATAES132A device to perform a simple AES-ECB mode encryption.

 

To perform this I use the Legacy command( 7.17 of datasheet) to encrypt 16 bytes of data. 

The Encryption works fine ( I compare the result with an online tool).

 

But how can I Decrypt this data? The legacy comman should also decrypt data, but if I pass the encrypt data as input, I dont obtain the plain text.

 

I should perform some operation on Encrypted data before pass it to Legacy command?

 

Thanks to all.


 
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I wrote to tech support , but after a week I have not been answered yet .
At this point you know explain the significance of the legacy command ?
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Hi all,

      I'm Using an ATAES132A device to obtain the random number. For this i am trying to read status register(0xFFF0) for communication confirmation. But there is no response from status register.

Can someone guide me if any sequence to read status register and execute commands

 

Thanks in advance...

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Hi All;

 

  I have the same issue.

 

I have ATAES132A (SPI part) on the board. After the board is up, I send a message (using SPI interface) to query decice status but I got no response from the device.

I set SPI configuration as follows:

  - transfer mode 0:

  - transfer 8 bit

  - clock: 1000000 Hz

/* Clock polarity. */
#define SPI_CLK_POLARITY 0

/* Clock phase. */
#define SPI_CLK_PHASE 0

/* Delay before SPCK. */
#define SPI_DLYBS 0x40

/* Delay between consecutive transfers. */
#define SPI_DLYBCT 0x10

 

I use two different messages:

  - device status register at the address 0xFFF0

 - status register command (RDRS)

 

I attach two responses from logic analyzer.

 

I hope  someone will help.

 

 

Thanks,

 

Nam Ninh

 

 

Attachment(s): 

NNinh

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legacy command is AES-ECB 

See https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation
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Hi, sorry for all this time, I don't receive e-mail notification....

@mallikarjuna.dsmr@gmail.com,

For read the status register I do:

- After send the command do Ack ACK-polling until the ATAES response;

- Read with normal I2C operation the status register.

This work,s for me.

@namnninh:

I can't see the second image, I use the I2C protocol, so I can't help you in SPI. For I2C the operation is above.

 

At the end I implemented a Rolling-Code using Legacy-command to generating a MAC.

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Hi all,

I also try to use ATAES132A but i cant read internal regsters such as (0xF040 - I2C_dev_add) or other.

I use I2C protocol to interface with device i can read the value of STATUS register but nothing more can someone help me?

I use PIC18F97J94.

 

Many Thanks!