The XML Signature implementation has been updated to Santuario 3.0.3. Support for four new SHA-3 based RSA-MGF1 signature methods have been added: `SHA3_224_RSA_MGF1`, `SHA3_256_RSA_MGF1`, `SHA3_384_RSA_MGF1`, and `SHA3_512_RSA_MGF1`. While these new algorithm URIs are not defined in `javax.xml.crypto.dsig.SignatureMethod` in the JDK update releases, they may be represented as string literals in order to be functionally equivalent. SHA-3 hash algorithm support was delivered to JDK 9 via [JEP 287](https://openjdk.org/jeps/287). Releases earlier than that may use third party security providers.