Fixes some typos in doc/ssl/

It might also call SSL_certs_clear() to delete any certificates associated

with the B<SSL> object.

The certificate callback functionality supercedes the (largely broken)

The certificate callback functionality supersedes the (largely broken)

functionality provided by the old client certificate callback interface.

It is B<always> called even is a certificate is already set so the callback

can modify or delete the existing certificate.

=head1 DESCRIPTION

The functions SSL_CTX_set_security_level() and SSL_set_security_level() set

the security level to B<level>. If not set the libary default security level

the security level to B<level>. If not set the library default security level

is used.

The functions SSL_CTX_get_security_level() and SSL_get_security_level()

=head1 DESCRIPTION

SSL_CTX_set_tlsext_ticket_key_cb() sets a callback fuction I<cb> for handling 

SSL_CTX_set_tlsext_ticket_key_cb() sets a callback function I<cb> for handling

session tickets for the ssl context I<sslctx>. Session tickets, defined in 

RFC5077 provide an enhanced session resumption capability where the server

implementation is not required to maintain per session state. It only applies

initialised with EVP_CIPHER_CTX_init and HMAC_CTX_init respectively.

For new sessions tickets, when the client doesn't present a session ticket, or

an attempted retreival of the ticket failed, or a renew option was indicated,

an attempted retrieval of the ticket failed, or a renew option was indicated,

the callback function will be called with I<enc> equal to 1. The OpenSSL

library expects that the function will set an arbitary I<name>, initialize

library expects that the function will set an arbitrary I<name>, initialize

I<iv>, and set the cipher context I<ctx> and the hash context I<hctx>.

The I<name> is 16 characters long and is used as a key identifier.

set using L<EVP_EncryptInit_ex>. The hmac context can be set using L<HMAC_Init_ex>.

When the client presents a session ticket, the callback function with be called 

with I<enc> set to 0 indicating that the I<cb> function should retreive a set

with I<enc> set to 0 indicating that the I<cb> function should retrieve a set

of parameters. In this case I<name> and I<iv> have already been parsed out of

the session ticket. The OpenSSL library expects that the I<name> will be used

to retrieve a cryptographic parameters and that the cryptographic context

I<ctx> will be set with the retreived parameters and the initialization vector

I<ctx> will be set with the retrieved parameters and the initialization vector

I<iv>. using a function like L<EVP_DecryptInit_ex>. The I<hctx> needs to be set

using L<HMAC_Init_ex>.

If the I<name> is still valid but a renewal of the ticket is required the

callback function should return 2. The library will call the callback again

with an arguement of enc equal to 1 to set the new ticket.

with an argument of enc equal to 1 to set the new ticket.

The return value of the I<cb> function is used by OpenSSL to determine what

further processing will occur. The following return values have meaning:

=item Z<>0

This indicates that it was not possible to set/retrieve a session ticket and 

the SSL/TLS session will continue by by negiotationing a set of cryptographic

the SSL/TLS session will continue by by negotiating a set of cryptographic

parameters or using the alternate SSL/TLS resumption mechanism, session ids.

If called with enc equal to 0 the library will call the I<cb> again to get

=head1 NOTES

Session resumption shortcuts the TLS so that the client certificate

negiotation don't occur. It makes up for this by storing client certificate

negotiation don't occur. It makes up for this by storing client certificate

an all other negotiated state information encrypted within the ticket. In a

resumed session the applications will have all this state information available

exactly as if a full negiotation had occured.

exactly as if a full negotiation had occurred.

If an attacker can obtain the key used to encrypt a session ticket, they can

obtain the master secret for any ticket using that key and decrypt any traffic

=head1 EXAMPLES

Reference Implemention:

Reference Implementation:

  SSL_CTX_set_tlsext_ticket_key_cb(SSL,ssl_tlsext_ticket_key_cb);

  ....