_mm_aesdeclast_si128
Microsoft Specific
Emits the Advanced Encryption Standard (AES) instruction aesdeclast. This instruction performs the final round of AES decryption.
__m128i _mm_aesdeclast_si128 (
__m128i v,
__m128i rkey
);
Parameters
Parameter
Description
[in] v
The state parameter that contains the data for the instruction to decrypt.
[in] rkey
The round key that this instruction uses to decrypt the data from v.
Return value
The decrypted data for v.
Requirements
Intrinsic
Architecture
_mm_aesdeclast_si128
x86, x64
Header file <wmmintrin.h>
Remarks
This instruction decrypts data by using an Equivalent Inverse Cipher with a 128 bit key. AES decryption requires 10 iterations of decryption and uses a cipher key that consists of 128 bits. The final iteration must be performed by this instruction. The previous nine iterations use _mm_aesdec_si128.
To perform the last round of encryption and be compliant with the AES, use _mm_aesenclast_si128.
Example
#include <wmmintrin.h>
#include <stdio.h>
int main()
{
__m128i a;
__m128i res;
__m128i key;
a.m128i_u64[1] = 0x8899AABBCCDDEEFF;
a.m128i_u64[0] = 0x0123456789ABCDEF;
key.m128i_u64[1] = 0x0022446688AACCEE;
key.m128i_u64[0] = 0x1133557799BBDDFF;
res = _mm_aesdeclast_si128( a, key );
printf_s("Original data: 0x%016I64x%016I64x\n",
a.m128i_u64[1], a.m128i_u64[0]);
printf_s("Decoded data: 0x%016I64x%016I64x\n",
res.m128i_u64[1], res.m128i_u64[0]);
return 0;
}
Original data: 0x8899aabbccddeeff0123456789abcdef Decoded data: 0xf210dd981fa4a49336cad57d9072bf9e