private static String getJavaxHmacName(HashType hashType) throws GeneralSecurityException {
    switch (hashType) {
      case SHA1:
        return "HmacSha1";
      case SHA256:
        return "HmacSha256";
      case SHA384:
        return "HmacSha384";
      case SHA512:
        return "HmacSha512";
      default:
        throw new GeneralSecurityException(
            "No getJavaxHmacName for given hash " + hashType + " known");
    }
  }
An implementation of the HKDF pseudorandom function, as given by RFC 5869.
java_src/src/main/java/com/google/crypto/tink/subtle/prf/HkdfStreamingPrf.java