From: Kim Phillips <kim.phillips@freescale.com>
Subject: Re: [PATCH 1/2] crypto: caam - add support for gcm(aes)
Date: Fri, 10 Oct 2014 09:36:15 -0500
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To: Ambarus Tudor-Dan-B38632 <tudor.ambarus@freescale.com>
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On Fri, 10 Oct 2014 03:47:18 -0500
Ambarus Tudor-Dan-B38632 <tudor.ambarus@freescale.com> wrote:

> On Thu, 9 Oct 2014 17:54:09 +0300
> Tudor Ambarus <tudor.ambarus@freescale.com> wrote:
> > +	/* Galois Counter Mode */
> > +	{
> > +		.name = "gcm(aes)",
> > +		.driver_name = "gcm-aes-caam",
> > +		.blocksize = 1,
> > +		.type = CRYPTO_ALG_TYPE_AEAD,
> > +		.template_aead = {
> > +			.setkey = gcm_setkey,
> > +			.setauthsize = gcm_setauthsize,
> > +			.encrypt = aead_encrypt,
> > +			.decrypt = aead_decrypt,
> > +			.givencrypt = NULL,
> > +			.geniv = "<built-in>",
> > +			.ivsize = 12,
> > +			.maxauthsize = 16,
> 
> AES_BLOCK_SIZE
> [TA] I think we shall not change the blocksize value to AES_BLOCK_SIZE.
> GCM uses a block cipher as a stream cipher. It generates encryption blocks, which are then XORed with the plaintext blocks to get the ciphertext. Just as with other stream ciphers, flipping a bit in the ciphertext produces a flipped bit in the plaintext at the same location.
> 

Sorry, I meant just .maxauthsize = AES_BLOCK_SIZE.

Kim