getScope(cr.seedDate, cr.region) + "\n" +
		cr.seedSignature + "\n" +
		emptySHA256 + "\n" +
		hashedChunk

	// Get hmac signing key.
	signingKey := getSigningKey(cr.cred.SecretKey, cr.seedDate, cr.region, serviceS3)

	// Calculate signature.
	newSignature := getSignature(signingKey, stringToSign)

	return newSignature
}

// getTrailerChunkSignature - get trailer chunk signature.

```
$ go run client-grants.go -cid PoEgXP6uVO45IsENRngDXj5Au5Ya -csec eKsw6z8CtOJVBtrOWvhRWL4TUCga

##### Credentials
{
 "accessKey": "NUIBORZYTV2HG2BMRSXR",
 "secretKey": "qQlP5O7CFPc5m5IXf1vYhuVTFj7BRVJqh0FqZ86S",
 "expiration": "2018-08-21T17:10:29-07:00",

```

Note: In the case of S3, it is possible to create a tier from MinIO running in EC2 to S3 using AWS role attached to EC2 as credentials instead of accesskey/secretkey:

```
mc admin tier add s3 source S3TIER --bucket s3bucket --prefix testprefix/ --use-aws-role
```

		t.Fatalf("unexpected error %v", err)
	}
	url.Path = t.TempDir()

	globalMinioHost, globalMinioPort = mustSplitHostPort(url.Host)
	globalNodeAuthToken, _ = authenticateNode(globalActiveCred.AccessKey, globalActiveCred.SecretKey)

	endpoint, err := NewEndpoint(url.String())
	if err != nil {
		t.Fatalf("NewEndpoint failed %v", endpoint)
	}

	if err = endpoint.UpdateIsLocal(); err != nil {
		t.Fatalf("UpdateIsLocal failed %v", err)

func (sys *BucketTargetSys) getRemoteTargetClient(tcfg *madmin.BucketTarget) (*TargetClient, error) {
	config := tcfg.Credentials
	creds := credentials.NewStaticV4(config.AccessKey, config.SecretKey, "")

	api, err := minio.New(tcfg.Endpoint, &minio.Options{
		Creds:     creds,
		Secure:    tcfg.Secure,
		Region:    tcfg.Region,
		Transport: globalRemoteTargetTransport,
	})
	if err != nil {

	})

	data, err := json.Marshal(resp)
	if err != nil {
		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
		return
	}

	encryptedData, err := madmin.EncryptData(cred.SecretKey, data)
	if err != nil {
		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
		return
	}

	writeSuccessResponseJSON(w, encryptedData)

	return f.tr.RoundTrip(r)
}

func (f *sftpDriver) getMinIOClient() (*minio.Client, error) {
	mcreds := credentials.NewStaticV4(
		f.permissions.CriticalOptions["AccessKey"],
		f.permissions.CriticalOptions["SecretKey"],
		f.permissions.CriticalOptions["SessionToken"],
	)
	// Set X-Forwarded-For on all requests.
	tr := http.RoundTripper(globalRemoteFTPClientTransport)
	if f.remoteIP != "" {

		region := globalSite.Region()
		if region == "" {
			region = "us-east-1"
		}
		clnt, err = minio.New(globalLocalNodeName, &minio.Options{
			Creds:     credentials.NewStaticV4(opts.creds.AccessKey, opts.creds.SecretKey, opts.creds.SessionToken),
			Secure:    globalIsTLS,
			Transport: globalRemoteTargetTransport,
			Region:    region,
		})
		if err != nil {
			return res, err
		}
	}

	var mu sync.Mutex

	err := ies.loadIAMConfig(ctx, &u, getUserIdentityPath(user, userType))
	if err != nil {
		if errors.Is(err, errConfigNotFound) {
			return "", errNoSuchUser
		}
		return "", err
	}
	return u.Credentials.SecretKey, nil
}

func (ies *IAMEtcdStore) loadUser(ctx context.Context, user string, userType IAMUserType, m map[string]UserIdentity) error {
	var u UserIdentity

    }
}
```

## 12. Security Considerations

### 12.1 Handle State Encryption
```java
public class SecureHandleStorage {
    private final SecretKey encryptionKey;
    
    public void saveEncrypted(HandleInfo handle, Path file) throws Exception {
        Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
        cipher.init(Cipher.ENCRYPT_MODE, encryptionKey);