final boolean hasEncryptionInfo() {
        ObjectMetadata metadata = s3obj.getObjectMetadata();
        Map<String, String> userMeta = metadata.getUserMetadata();
        return userMeta != null
            && userMeta.containsKey(Headers.CRYPTO_IV)
            && (userMeta.containsKey(Headers.CRYPTO_KEY_V2)
                || userMeta.containsKey(Headers.CRYPTO_KEY));
    }
Returns true if this S3 object has the encryption information stored
as user meta data; false otherwise.
aws-java-sdk-s3/src/main/java/com/amazonaws/services/s3/internal/crypto/v2/S3ObjectWrapper.java