1 files changed, 0 insertions, 170 deletions
diff --git a/crypto/openssl/doc/ssl/SSL_CTX_set_tmp_dh_callback.pod b/crypto/openssl/doc/ssl/SSL_CTX_set_tmp_dh_callback.pod
deleted file mode 100644
index 29d1f8a6fbfe7..0000000000000
--- a/crypto/openssl/doc/ssl/SSL_CTX_set_tmp_dh_callback.pod
+++ /dev/null
@@ -1,170 +0,0 @@
-=pod
-
-=head1 NAME
-
-SSL_CTX_set_tmp_dh_callback, SSL_CTX_set_tmp_dh, SSL_set_tmp_dh_callback, SSL_set_tmp_dh - handle DH keys for ephemeral key exchange
-
-=head1 SYNOPSIS
-
- #include <openssl/ssl.h>
-
- void SSL_CTX_set_tmp_dh_callback(SSL_CTX *ctx,
-            DH *(*tmp_dh_callback)(SSL *ssl, int is_export, int keylength));
- long SSL_CTX_set_tmp_dh(SSL_CTX *ctx, DH *dh);
-
- void SSL_set_tmp_dh_callback(SSL_CTX *ctx,
-            DH *(*tmp_dh_callback)(SSL *ssl, int is_export, int keylength));
- long SSL_set_tmp_dh(SSL *ssl, DH *dh)
-
- DH *(*tmp_dh_callback)(SSL *ssl, int is_export, int keylength));
-
-=head1 DESCRIPTION
-
-SSL_CTX_set_tmp_dh_callback() sets the callback function for B<ctx> to be
-used when a DH parameters are required to B<tmp_dh_callback>.
-The callback is inherited by all B<ssl> objects created from B<ctx>.
-
-SSL_CTX_set_tmp_dh() sets DH parameters to be used to be B<dh>.
-The key is inherited by all B<ssl> objects created from B<ctx>.
-
-SSL_set_tmp_dh_callback() sets the callback only for B<ssl>.
-
-SSL_set_tmp_dh() sets the parameters only for B<ssl>.
-
-These functions apply to SSL/TLS servers only.
-
-=head1 NOTES
-
-When using a cipher with RSA authentication, an ephemeral DH key exchange
-can take place. Ciphers with DSA keys always use ephemeral DH keys as well.
-In these cases, the session data are negotiated using the
-ephemeral/temporary DH key and the key supplied and certified
-by the certificate chain is only used for signing.
-Anonymous ciphers (without a permanent server key) also use ephemeral DH keys.
-
-Using ephemeral DH key exchange yields forward secrecy, as the connection
-can only be decrypted, when the DH key is known. By generating a temporary
-DH key inside the server application that is lost when the application
-is left, it becomes impossible for an attacker to decrypt past sessions,
-even if he gets hold of the normal (certified) key, as this key was
-only used for signing.
-
-In order to perform a DH key exchange the server must use a DH group
-(DH parameters) and generate a DH key. The server will always generate a new
-DH key during the negotiation, when the DH parameters are supplied via
-callback and/or when the SSL_OP_SINGLE_DH_USE option of
-L<SSL_CTX_set_options(3)|SSL_CTX_set_options(3)> is set. It will
-immediately create a DH key, when DH parameters are supplied via
-SSL_CTX_set_tmp_dh() and SSL_OP_SINGLE_DH_USE is not set. In this case,
-it may happen that a key is generated on initialization without later
-being needed, while on the other hand the computer time during the
-negotiation is being saved.
-
-If "strong" primes were used to generate the DH parameters, it is not strictly
-necessary to generate a new key for each handshake but it does improve forward
-secrecy. If it is not assured, that "strong" primes were used (see especially
-the section about DSA parameters below), SSL_OP_SINGLE_DH_USE must be used
-in order to prevent small subgroup attacks. Always using SSL_OP_SINGLE_DH_USE
-has an impact on the computer time needed during negotiation, but it is not
-very large, so application authors/users should consider to always enable
-this option.
-
-As generating DH parameters is extremely time consuming, an application
-should not generate the parameters on the fly but supply the parameters.
-DH parameters can be reused, as the actual key is newly generated during
-the negotiation. The risk in reusing DH parameters is that an attacker
-may specialize on a very often used DH group. Applications should therefore
-generate their own DH parameters during the installation process using the
-openssl L<dhparam(1)|dhparam(1)> application. In order to reduce the computer
-time needed for this generation, it is possible to use DSA parameters
-instead (see L<dhparam(1)|dhparam(1)>), but in this case SSL_OP_SINGLE_DH_USE
-is mandatory.
-
-Application authors may compile in DH parameters. Files dh512.pem,
-dh1024.pem, dh2048.pem, and dh4096 in the 'apps' directory of current
-version of the OpenSSL distribution contain the 'SKIP' DH parameters,
-which use safe primes and were generated verifiably pseudo-randomly.
-These files can be converted into C code using the B<-C> option of the
-L<dhparam(1)|dhparam(1)> application.
-Authors may also generate their own set of parameters using
-L<dhparam(1)|dhparam(1)>, but a user may not be sure how the parameters were
-generated. The generation of DH parameters during installation is therefore
-recommended.
-
-An application may either directly specify the DH parameters or
-can supply the DH parameters via a callback function. The callback approach
-has the advantage, that the callback may supply DH parameters for different
-key lengths.
-
-The B<tmp_dh_callback> is called with the B<keylength> needed and
-the B<is_export> information. The B<is_export> flag is set, when the
-ephemeral DH key exchange is performed with an export cipher.
-
-=head1 EXAMPLES
-
-Handle DH parameters for key lengths of 512 and 1024 bits. (Error handling
-partly left out.)
-
- ...
- /* Set up ephemeral DH stuff */
- DH *dh_512 = NULL;
- DH *dh_1024 = NULL;
- FILE *paramfile;
-
- ...
- /* "openssl dhparam -out dh_param_512.pem -2 512" */
- paramfile = fopen("dh_param_512.pem", "r");
- if (paramfile) {
-   dh_512 = PEM_read_DHparams(paramfile, NULL, NULL, NULL);
-   fclose(paramfile);
- }
- /* "openssl dhparam -out dh_param_1024.pem -2 1024" */
- paramfile = fopen("dh_param_1024.pem", "r");
- if (paramfile) {
-   dh_1024 = PEM_read_DHparams(paramfile, NULL, NULL, NULL);
-   fclose(paramfile);
- }
- ...
-
- /* "openssl dhparam -C -2 512" etc... */
- DH *get_dh512() { ... }
- DH *get_dh1024() { ... }
-
- DH *tmp_dh_callback(SSL *s, int is_export, int keylength)
- {
-    DH *dh_tmp=NULL;
-
-    switch (keylength) {
-    case 512:
-      if (!dh_512)
-        dh_512 = get_dh512();
-      dh_tmp = dh_512;
-      break;
-    case 1024:
-      if (!dh_1024) 
-        dh_1024 = get_dh1024();
-      dh_tmp = dh_1024;
-      break;
-    default:
-      /* Generating a key on the fly is very costly, so use what is there */
-      setup_dh_parameters_like_above();
-    }
-    return(dh_tmp);
- }
-
-=head1 RETURN VALUES
-
-SSL_CTX_set_tmp_dh_callback() and SSL_set_tmp_dh_callback() do not return
-diagnostic output.
-
-SSL_CTX_set_tmp_dh() and SSL_set_tmp_dh() do return 1 on success and 0
-on failure. Check the error queue to find out the reason of failure.
-
-=head1 SEE ALSO
-
-L<ssl(3)|ssl(3)>, L<SSL_CTX_set_cipher_list(3)|SSL_CTX_set_cipher_list(3)>,
-L<SSL_CTX_set_tmp_rsa_callback(3)|SSL_CTX_set_tmp_rsa_callback(3)>,
-L<SSL_CTX_set_options(3)|SSL_CTX_set_options(3)>,
-L<ciphers(1)|ciphers(1)>, L<dhparam(1)|dhparam(1)>
-
-=cut