Specifies an authentication credential for the
originator. Restrictions: The Meta element type specifies any
meta-information about the credentials. The Type and Format element
types within the Meta element type specify the credential scheme type
and format, respectively. The default type is syncml:auth-basic for the
"Basic" form of authentication. The type value syncml:auth-md5 MUST be
explicitly specified to indicate the SyncML "MD5 Digest" authentication
scheme. The format MUST be b64, when using the clear-text, XML
representation. However, when using "Basic" form of authentication, the
b64 format does not indicate that the credentials are base64 encoded
twice. The Data element type specifies the credential value. The types
for these SyncML authentication schemes are specified in Section 4.3,
"Security", of this specification. If absent, and no other
authentication credential was specified in either a parent command or in
the SyncHdr element type, then no authentication credential is
specified. If an authentication credential was specified by a parent
command or in the SyncHdr element type, then that authentication
credential specified there is assumed to be sufficient for the operation
specified by the current element type. Specifying insufficient
authentication credentials will result in a (401) Unauthorized exception
condition. If the authentication challenge is received (See the Chal
element type) for the request, the credential type and format of the
next request MUST be applied to it.