@Override public Key getEncryptionSecret() {
    return jwtEncryptionKey;
  }
Default implementation of {@link JwtSecretProvider}.

1. It first tries to get shared secret from conf {@link HiveConf.ConfVars#LLAP_EXTERNAL_CLIENT_CLOUD_JWT_SHARED_SECRET}
using {@link Configuration#getPassword(String)}.

2. If not found, it tries to read from env var {@link #LLAP_EXTERNAL_CLIENT_CLOUD_JWT_SHARED_SECRET_ENV_VAR}.

If secret is not found even after 1) and 2), {@link #init(Configuration)} methods throws {@link IllegalStateException}.

Length of shared secret provided in 1) or 2) should be &gt; 32 bytes.

It uses the same encryption and decryption secret which can be used to sign and verify JWT.
llap-common/src/java/org/apache/hadoop/hive/llap/security/DefaultJwtSharedSecretProvider.java