Am Dienstag, 18. November 2014, 22:06:31 schrieb Herbert Xu: Hi Herbert, > On Sun, Nov 16, 2014 at 03:23:50AM +0100, Stephan Mueller wrote: > > AEAD requires the following data in addition to normal symmetric > > > > ciphers: > > * Associated authentication data of arbitrary length > > > > * Authentication tag for decryption > > > > * Length of authentication tag for encryption > > > > The authentication tag data is communicated as part of the actual > > ciphertext as mandated by the kernel crypto API. Therefore we only need > > to provide a user space interface for the associated authentication data > > as well as for the authentication tag length. > > > > This patch adds both as a setsockopt interface that is identical to the > > AF_ALG interface for setting an IV and for selecting the cipher > > operation type (encrypt or decrypt). > > > > Signed-off-by: Stephan Mueller <smueller@xxxxxxxxxx> > > I don't like the fact that we're putting arbitrary limits on > the AD, as well as the fact that the way you're doing it the > AD has to be copied. > > How about simply saying that the first X bytes of the input > shall be the AD? That is a very good idea. To cover that approach, the kernel needs to be informed about the length of the authentication data size to separate the ciphertext/plaintext from the authentication data. To cover that, I would recommend to simply send a u32 value to the kernel for the AD size instead of the AD. The kernel then can adjust the pointers as necessary. I will update the patch in the next days to cover that scenario. Thanks -- Ciao Stephan -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
