A Lightweight AES Coprocessor Based on RISC-V Custom Instructions
Algorithm 1
Software and hardware codesign.
Input: The address of all parameters, including the key, the plaintext (or message), the ciphertext (or tag) and the IV. Length of the plaintext (or message).
(1)
Function AES_CBC_ENCRY(,,,):
(2)
ifthen
(3)
fordo
(4)
(5)
end
(6)
CBC_INIT //The embedded custom instruction
(7)
LOOP //The embedded custom instruction
/∗ If the plaintext needs to be protected, then ∗/
(8)
fordo
(9)
(10)
end
(11)
end
(12)
Function AES_CMAC_AUTHEN :
(13)
ifthen
(14)
CMAC_INIT //The embedded custom instruction
(15)
LOOP //The embedded custom instruction
(16)
end
/∗ The encryption procedure is as follows ∗/
/∗ Here is key agreement ∗/
(17)
KEY_UPDATE //The embedded custom instruction
/∗ Here is IV synchronisation and plaintext padding ∗/
