krb5_mk_safe -  Format a KRB-SAFE message. 
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.. c:function:: krb5_error_code krb5_mk_safe(krb5_context context, krb5_auth_context auth_context, const krb5_data * userdata, krb5_data * der_out, krb5_replay_data * rdata_out)

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:param:

	          **[in]** **context** - Library context

	          **[in]** **auth_context** - Authentication context

	          **[in]** **userdata** - User data in the message

	          **[out]** **der_out** - Formatted **KRB-SAFE** buffer

	          **[out]** **rdata_out** - Replay data. Specify NULL if not needed


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:retval:
         -   0   Success; otherwise - Kerberos error codes


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This function creates an integrity protected **KRB-SAFE** message using data supplied by the application.



Fields in *auth_context* specify the checksum type, the keyblock that can be used to seed the checksum, full addresses (host and port) for the sender and receiver, and KRB5_AUTH_CONTEXT flags.



The local address in *auth_context* must be set, and is used to form the sender address used in the KRB-SAFE message. The remote address is optional; if specified, it will be used to form the receiver address used in the message.



If the KRB5_AUTH_CONTEXT_DO_TIME flag is set in *auth_context* , a timestamp is included in the KRB-SAFE message, and an entry for the message is entered in an in-memory replay cache to detect if the message is reflected by an attacker. If KRB5_AUTH_CONTEXT_DO_TIME is not set, no replay cache is used. If KRB5_AUTH_CONTEXT_RET_TIME is set in *auth_context* , a timestamp is included in the KRB-SAFE message and is stored in *rdata_out* .



If either KRB5_AUTH_CONTEXT_DO_SEQUENCE or KRB5_AUTH_CONTEXT_RET_SEQUENCE is set, the *auth_context* local sequence number is included in the KRB-SAFE message and then incremented. If KRB5_AUTH_CONTEXT_RET_SEQUENCE is set, the sequence number used is stored in *rdata_out* .



Use krb5_free_data_contents() to free *der_out* when it is no longer needed.










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.. note::

	 The *rdata_out* argument is required if the KRB5_AUTH_CONTEXT_RET_TIME or KRB5_AUTH_CONTEXT_RET_SEQUENCE flag is set in *auth_context* .
 



