Identifiers:
   http://www.w3.org/2007/05/xmldsig-more#sha3-224-rsa-MGF1
   http://www.w3.org/2007/05/xmldsig-more#sha3-256-rsa-MGF1
   http://www.w3.org/2007/05/xmldsig-more#sha3-384-rsa-MGF1
   http://www.w3.org/2007/05/xmldsig-more#sha3-512-rsa-MGF1

   http://www.w3.org/2007/05/xmldsig-more#md2-rsa-MGF1
   http://www.w3.org/2007/05/xmldsig-more#md5-rsa-MGF1
   http://www.w3.org/2007/05/xmldsig-more#sha1-rsa-MGF1
   http://www.w3.org/2007/05/xmldsig-more#sha224-rsa-MGF1
   http://www.w3.org/2007/05/xmldsig-more#sha256-rsa-MGF1
   http://www.w3.org/2007/05/xmldsig-more#sha384-rsa-MGF1
   http://www.w3.org/2007/05/xmldsig-more#sha512-rsa-MGF1
   http://www.w3.org/2007/05/xmldsig-more#ripemd128-rsa-MGF1
   http://www.w3.org/2007/05/xmldsig-more#ripemd160-rsa-MGF1
   http://www.w3.org/2007/05/xmldsig-more#whirlpool-rsa-MGF1