Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
IronPort-SDR: puXLyySm9QSp17u6iadahGKiDVBfVxIaoBQJ77jM0lZ8VFRTRz3shqjSaFAWKeqi0l8tfiZYkw
 NUwrqn4IjONw==
IronPort-SDR: MIIvnD102MDN9s0bZ67NOn1YIW7aWVAYOO9Z9hr/zSf5OJ8LQ9CZ2czJZz11gbDvznseT5c1XE
 EcgnpZfg90OA==
Date:   Tue, 16 Jun 2020 09:26:04 +0530
From:   Anshuman Gupta <anshuman.gupta@intel.com>
To:     Stephan Mueller <smueller@chronox.de>
Cc:     linux-crypto@vger.kernel.org
Subject: Re: [Query] RSA SHA-384 signature verification
Message-ID: <20200616035603.GG14085@intel.com>
References: <20200615170413.GF14085@intel.com>
 <1730161.mygNopSbl3@tauon.chronox.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <1730161.mygNopSbl3@tauon.chronox.de>
User-Agent: Mutt/1.9.4 (2018-02-28)
Sender: linux-crypto-owner@vger.kernel.org
Precedence: bulk

On 2020-06-15 at 21:25:58 +0200, Stephan Mueller wrote:
> Am Montag, 15. Juni 2020, 19:04:14 CEST schrieb Anshuman Gupta:
> 
> Hi Anshuman,
> 
> > Hi ,
> > I wanted to verify a RSA SHA-384 signature.
> > I am using crypto_alloc_shash(), crypto_shash_digest() API to extract
> > the SHA-384 digest.
> > I am having public key along with the sha-384 digest extracted from raw data
> > and signature. AFAIU understand from crypto documentation that i need to
> > verify the signature by importing public key to akcipher/skcipher API.
> > Here i am not sure which cipher API to prefer symmetric key cipher or
> > asymmetric key cipher API.
> > 
> > There are two types of API to import the key.
> > crypto_skcipher_setkey()
> > crypto_akcipher_set_pub_key()
> > 
> > Also i am not sure exactly which algo to use for RSA-SHA384 signature
> > verification.
> > 
> > Any help or inputs from crypto community will highly appreciated.
> 
> akcipher: asymmetric key crypto
> 
> skcipher: symmetric key crypto
Many thanks for your input, based upon your inputs i should use
akcipher.
Actually tried to grep crypto_akcipher_set_pub_key() but there are not any
usages of this API in Linux drivers.
What is the preferred method to verify a RSA signature inside any Linux
GPL driver, is there any standard interface API to verify RSA signature
by importing input of raw data and public key or else
it is recommended method to use below set low level of API 
crypto_alloc_akcipher(), akcipher_request_alloc(),
akcipher_request_set_crypt(), crypto_akcipher_verify().
Thanks,
Anshuman.

> > 
> > Thanks ,
> > Anshuman Gupta.
> 
> 
> Ciao
> Stephan
> 
>