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From:   Stephan Mueller <smueller@chronox.de>
To:     "Bhat, Jayalakshmi Manjunath" <jayalakshmi.bhat@hp.com>
Cc:     "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>
Subject: Re: How to use nonce in DRBG functions.
Date:   Mon, 02 Sep 2019 11:05:19 +0200
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Am Sonntag, 1. September 2019, 20:52:24 CEST schrieb Bhat, Jayalakshmi 
Manjunath:

Hi Jayalakshmi,

> Hi All,
> 
> I am trying to implement DRBG CAVS test harness function for Linux Kernel
> crypto DRBG with the following requirements. 1.	Derivate function is
> enabled.
> 	2.	prediction resistance is not enabled
> 	3.	Entropy input length is 256
> 	4.	Nonce length is 256
> 	5.	Mode is AES-CTR 256
> 	6.	Reseed is supported
> 	7.	Intended use generate.
> 
> Thus inputs are
> 	1.	Entropy Input
> 	2.	Nonce
> 	3.	Entropy Additional Input
> 
> Flow goes something like below
> 	drbg_string_fill(&testentropy, test->entropy, test->entropylen);
> 	drbg_string_fill(&pers, test->pers, test->perslen);
> 	ret = crypto_drbg_reset_test(drng, &pers, &test_data);
> 	drbg_string_fill(&addtl, test->addtla, test->addtllen);
> 	ret = crypto_drbg_get_bytes_addtl(drng, buf, test->expectedlen, 
&addtl);
> 
> I am not finding a way to input nonce. Please can anyone tell me how to
> input nonce.

The entropy string for the DRBG is the CAVS entropy concatenated with the 
nonce as defined in SP800-90A for each instantiate process of each DRBG.
> 
> Regards,
> Jayalakshmi


Ciao
Stephan