message: Simplifying and clarifying the descriptions of SigUtil.validateRsaSsaPssParams() and SigUtil.toHashType(). The documentation now explicitly says that SHA384 is also a supported hash function.
diff: @@ -86,18 +86,10 @@ final class SigUtil {
  * Validates RsaSsaPss's parameters.
  *
  * <ul>
  - * <li>As SHA1 is unsafe, we will only support SHA256 and SHA512 for digital signature.
  - * <li>The most common use case is that MGF1 hash is the same as signature hash. This is
  - * recommended by RFC https://tools.ietf.org/html/rfc8017#section-8.1. While using different
  - * hashes doesn't cause security vulnerabilities, there is also no good reason to support
  - * different hashes. Furthermore:
  + * <li>The MGF1 hash function must be the same as the signature hash function.
  + * <li>The hash function used must be either SHA256, SHA384, or SHA512.
  + * <li>The salt length must be non-zero.
  * <ul>
  - * <li>Golang does not support different hashes.
  - * <li>BoringSSL supports different hashes just because of historical reason. There is no
  - * real use case.
  - * <li>Conscrypt/BouncyCastle do not support different hashes.
  - * </ul>
  - * </ul>
  *
  * @param params the RsaSsaPssParams protocol buffer.
  * @throws GeneralSecurityException iff it's invalid.
  @@ -113,7 +105,11 @@ final class SigUtil {
  }
  }
  - /** Converts protobuf enum {@code HashType} to raw Java enum {@code Enums.HashType}. */
  + /**
  + * Converts protobuf enum {@code HashType} to raw Java enum {@code Enums.HashType}.
  + *
  + * @throws GeneralSecurityException if the HashType is not SHA256, SHA384, or SHA512.
  + */
  public static Enums.HashType toHashType(HashType hash) throws GeneralSecurityException {
  switch (hash) {
  case SHA256:
  