Tell me please, how can I check if OpenSSL is support/use the Intel AES-NI?
Look in /proc/cpuinfo . If you have the aes flag then your CPU has AES support.
You can see that AES speed with AES-NI acceleration is about five times higher than non-acceleration. This confirms that AES-NI is enabled for OpenSSL.
From the System Utilities screen, select System Configuration > BIOS/Platform Configuration (RBSU) > Server Security > Processor AES-NI Support and press Enter. Select a setting and press Enter. Enabled—Enables AES-NI support.
Use this option to enable or disable the Advanced Encryption Standard Instruction Set in the processor.
how can I check if OpenSSL is support/use the Intel AES-NI?
Its not that simple, though it should be. OpenSSL used to provide a function to get the capabilities detected for an ia32 processor, but its no longer available. See the discussion of OPENSSL_ia32cap_loc
in the OPENSSL_ia32cap
man page. Also see Verify AES-NI use at runtime? on the OpenSSL mailing list.
If you are linking to the OpenSSL static library, then you can use:
extern unsigned int OPENSSL_ia32cap_P[];
# define AESNI_CAPABLE (OPENSSL_ia32cap_P[1]&(1<<(57-32)))
if(AESNI_CAPABLE)
/* AES-NI is available */
If you are linking to the OpenSSL shared object, then the symbol OPENSSL_ia32cap_P
is not exported. In this case, you need to write your own detection code.
I don't even bother with OpenSSL since it only works with static linking of the library. I shared the code I use for detection below. I believe I ripped a significant portion of it from Dave Johnston of Intel (he designed the RDRAND circuit).
Note: the code below could incorrectly reject an AMD processor with AES-NI. I don't have a processor to test on, so I can't offer the code.
Note: the code below will not perform as expected under Valgrind. There's no emulation for the AES-NI or RDRAND instructions, so Valgrind returns a "doctored" value from CPUID
so it appears they are not available. See Incorrect results from inline assembly when running under Valgrind on the mailing list.
Even though AES-NI is available, it does not mean you are going to use it.
If you use the low level primitives like AES_*
, then you will not use AES-NI because its a software implementation.
If you use the high level EVP_*
gear, then you will use AES-NI if its available. The library will switch to AES-NI automatically.
If AES-NI is available but you don't want to use it, then perform the following before launching you program:
$ export OPENSSL_ia32cap="~0x200000200000000"
You can test the speed difference with the following OpenSSL command. Toggle the export above to see the differences:
$ openssl speed -elapsed -evp aes-128-ecb
struct CPUIDinfo {
unsigned int EAX;
unsigned int EBX;
unsigned int ECX;
unsigned int EDX;
};
int HasIntelCpu();
int HasAESNI();
int HasRDRAND();
void cpuid_info(CPUIDinfo *info, const unsigned int func,
const unsigned int subfunc);
int HasIntelCpu() {
CPUIDinfo info;
cpuid_info(&info, 0, 0);
if (memcmp((char *) (&info.EBX), "Genu", 4) == 0
&& memcmp((char *) (&info.EDX), "ineI", 4) == 0
&& memcmp((char *) (&info.ECX), "ntel", 4) == 0) {
return 1;
}
return 0;
}
int HasAESNI() {
if (!HasIntelCpu())
return 0;
CPUIDinfo info;
cpuid_info(&info, 1, 0);
static const unsigned int AESNI_FLAG = (1 << 25);
if ((info.ECX & AESNI_FLAG) == AESNI_FLAG)
return 1;
return 0;
}
int HasRDRAND() {
if (!HasIntelCpu())
return 0;
CPUIDinfo info;
cpuid_info(&info, 1, 0);
static const unsigned int RDRAND_FLAG = (1 << 30);
if ((info.ECX & RDRAND_FLAG) == RDRAND_FLAG)
return 1;
return 0;
}
void cpuid_info(CPUIDinfo *info, unsigned int func, unsigned int subfunc) {
__asm__ __volatile__ (
"cpuid"
: "=a"(info->EAX), "=b"(info->EBX), "=c"(info->ECX), "=d"(info->EDX)
: "a"(func), "c"(subfunc)
);
}
A couple quick one liners built from the information provided by jww:
openssl speed -elapsed -evp aes-128-cbc ... OPENSSL_ia32cap="~0x200000200000000" openssl speed -elapsed -evp aes-128-cbc ...
Output of the first line should be significantly faster than the second. In my case on a i5 test machine, nearly double.
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