On Wed, May 28, 2003, p b wrote:
>
>
> I had made some test: in fact when I changed the iv, I only changed few
> bits, so the uncrypted file "seams" to be the same. (whatever the value of
> iv, only the first bloc change). It's ok.
>
>
That's expected behaviour for CBC mode.
> > phbgt> In the man, when you write EVP_CipherInit " always use the
> > phbgt> default cipher implementation", is that mean that even using
> > phbgt> EVP_get_cipherbyname("aes-256-cbc"), the cipher is not set to
> > phbgt> "aes-256-cbc"?
> >
>
> With this type of initialisation, EVP_CipherInit use aes-256-cbc. In fact,
> it seams that there's no default cipher in openssl.
>
What it means is that it uses the default implementation *of that cipher*.
This will normally be the builting software version.
There can however be multiple implementations of a given cipher for example
hardware implementations in ENGINEs.
An ENGINE can replace the default implementation so that for example an
accelerated hardware version is used by default instead of the software one.
It is also possible for an application to specify non default implementations
of ciphers if they wish to.
Steve.
--
Dr Stephen N. Henson.
Core developer of the OpenSSL project: http://www.openssl.org/
Freelance consultant see: http://www.drh-consultancy.demon.co.uk/
Email: [EMAIL PROTECTED], PGP key: via homepage.
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