Re: [openssl-users] Does openssl pick low level interface or high level interface to do encrypt?

2017-08-10 Thread Viktor Dukhovni
On Wed, Aug 09, 2017 at 01:08:47PM +, - JinsongJi wrote:

> For one simple operation: openssl enc -aes-256-cbc -salt -in foo.txt -out 
> foo.enc
> Does openssl pick classic implementation or AES-NI implementation to do this 
> encrypt?

The enc(1) command uses the EVP API to access the requested symmetric
cipher.  As a result, AES-NI and the like will be used when supported
by the hardware and enabled in your OpenSSL library.

> Does any user/application always pick classic implementation for
> AES operation regardless of AES-NI improves speed much?

If the application uses EVP_get_cipherbyname() and the like, it
gets the best available implementation of the cipher.  If it
bypasses EVP it may get a slower implementation and/or one that
has less side-channel resistance.

Bottom-line, use EVP.

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Re: [openssl-users] Does openssl pick low level interface or high level interface to do encrypt?

2017-08-10 Thread Salz, Rich via openssl-users
What OpenSSL does is not necessarily obvious.  The INSTALL document talks about 
the no-asm configuration option.  Details about what the assembler code does in 
terms of optimization are only available by reading the source code comments in 
the various Perl files that generate the assembler, mostly.

On x86, the assembly code uses the CPUID instruction (see the 
OPENSSL_ia32cap.pod manpage) to determine if various instructions (AES, SSE, 
MMX, etc) are available and will use them if so.  For other processors, similar 
tests are performed if at all possible.

I have added this to the FAQ

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From: - JinsongJi [mailto:jjsb...@hotmail.com]
Sent: Wednesday, August 09, 2017 9:09 AM
To: openssl-users@openssl.org
Subject: [openssl-users] Does openssl pick low level interface or high level 
interface to do encrypt?

Hi,


For one simple operation: openssl enc -aes-256-cbc -salt -in foo.txt -out 
foo.enc
Does openssl pick classic implementation or AES-NI implementation to do this 
encrypt?

Does any user/application always pick classic implementation for AES operation 
regardless of AES-NI improves speed much?

Is there any document about this interface selection?

Thanks,
Jinsong
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[openssl-users] Does openssl pick low level interface or high level interface to do encrypt?

2017-08-10 Thread - JinsongJi
Hi,


For one simple operation: openssl enc -aes-256-cbc -salt -in foo.txt -out 
foo.enc
Does openssl pick classic implementation or AES-NI implementation to do this 
encrypt?

Does any user/application always pick classic implementation for AES operation 
regardless of AES-NI improves speed much?

Is there any document about this interface selection?

Thanks,
Jinsong
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