private static com.google.crypto.tink.daead.AesSivKey createKey(OutputPrefixType outputPrefixType)
      throws GeneralSecurityException {
    return com.google.crypto.tink.daead.AesSivKey.builder()
        .setParameters(
            AesSivParameters.builder()
                .setKeySizeBytes(64)
                .setVariant(OUTPUT_PREFIX_TYPE_CONVERTER.fromProtoEnum(outputPrefixType))
                .build())
        .setKeyBytes(SecretBytes.copyFrom(KEY_BYTES, InsecureSecretKeyAccess.get()))
        .setIdRequirement(outputPrefixType == OutputPrefixType.RAW ? null : KEY_ID)
        .build();
  }
This encrypts using the subtle Tink API, then decrypts using the custom key manager with a
keyset with a single key.
java_src/src/test/java/com/google/crypto/tink/daead/KeyManagerIntegrationTest.java