Aes Key Register 0 (Aes_Keyr0) (Lsb: Key [31:0]) - ST STM32L4x6 Reference Manual

RM0351
25.14.5

AES key register 0 (AES_KEYR0) (LSB: key [31:0])

Address offset: 0x10
Reset value: 0x0000 0000
31 30 29 28
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Bits 31:0 KEYR0[31:0]: Data output register (LSB key [31:0])
This register must be written before the EN bit in the AES_CR register is set:
In mode 1 (encryption), mode 2 (key derivation) and mode 4 (key derivation + decryption), the value to
be written represents the encryption key from LSB, meaning key [31:0].
In mode 3 (decryption), the value to be written represents the decryption key from LSB, meaning key
[31:0]. When the register is written with the encryption key in this decryption mode, reading it before
the AES is enabled will return the encryption value. Reading it after CCF flag is set will return the
derivation key.
Reading this register while AES is enabled returns an unpredictable value.
Note: This register does not contain the derivation key in mode 4 (derivation key + decryption). It
always contains the encryption key value.
25.14.6 AES key register 1 (AES_KEYR1) (key[63:32])
Address offset: 0x14
Reset value: 0x0000 0000
31 30 29 28
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Bits 31:0 KEYR1[31:0]: Data output register (key [63:32])
Refer to the description of AES_KEYR0.
Advanced encryption standard hardware accelerator (AES)
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KEYR0[31:16]
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11 10 9 8
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27 26 25 24
KEYR1[31:16]
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11 10 9 8
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DocID024597 Rev 3
23 22 21
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7 6 5
KEYR0[15:0]
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23 22 21
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7 6 5
KEYR1[15:0]
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20 19 18 17
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4 3 2 1
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20 19 18 17
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4 3 2 1
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