assertNotNull(derivedKey);
        assertEquals(16, derivedKey.length);

        // Test with a different key size
        KerberosKey key256 = new KerberosKey(TEST_PRINCIPAL, new byte[32], PacSignature.ETYPE_AES256_CTS_HMAC_SHA1_96, 0);
        byte[] derivedKey256 = PacMac.deriveKeyAES(key256, constant);
        assertNotNull(derivedKey256);
        assertEquals(32, derivedKey256.length);
    }

    /**

	_ "golang.org/x/crypto/sha3"
)

// Specific instances for EC256 and company
var (
	SigningMethodES3256 *jwt.SigningMethodECDSA
	SigningMethodES3384 *jwt.SigningMethodECDSA
	SigningMethodES3512 *jwt.SigningMethodECDSA
)

func init() {
	// ES256
	SigningMethodES3256 = &jwt.SigningMethodECDSA{Name: "ES3256", Hash: crypto.SHA3_256, KeySize: 32, CurveBits: 256}

			{
				DefaultEncryptionAction: EncryptionAction{
					Algorithm: AES256,
				},
			},
		},
	}

	actualAES256Config := &BucketSSEConfig{
		XMLNS: xmlNS,
		XMLName: xml.Name{
			Local: "ServerSideEncryptionConfiguration",
		},
		Rules: []Rule{
			{
				DefaultEncryptionAction: EncryptionAction{
					Algorithm: AES256,
				},
			},
		},
	}

	actualKMSConfig := &BucketSSEConfig{

	"github.com/minio/minio/internal/crypto"
	xhttp "github.com/minio/minio/internal/http"
)

const (
	// AES256 is used with SSE-S3
	AES256 Algorithm = "AES256"
	// AWSKms is used with SSE-KMS
	AWSKms Algorithm = "aws:kms"
)

// Algorithm - represents valid SSE algorithms supported; currently only AES256 is supported
type Algorithm string

// UnmarshalXML - Unmarshals XML tag to valid SSE algorithm

	Metadata       map[string]string

	ExpectedErr error
}{
	{ // 0 - Valid HTTP headers and valid metadata entries for bucket/object
		Headers: http.Header{
			"X-Amz-Server-Side-Encryption-Customer-Algorithm": []string{"AES256"},
			"X-Amz-Server-Side-Encryption-Customer-Key":       []string{"MzJieXRlc2xvbmdzZWNyZXRrZXltdXN0cHJvdmlkZWQ="},
			"X-Amz-Server-Side-Encryption-Customer-Key-Md5":   []string{"7PpPLAK26ONlVUGOWlusfg=="},
		},

	if len(b) == 0 {
		return b, kms.AES256
	}

	if b[0] == '{' && b[len(b)-1] == '}' { // JSON object
		var c ciphertext
		if err := c.UnmarshalJSON(b); err != nil {
			// It may happen that a random ciphertext starts with '{' and ends with '}'.
			// In such a case, parsing will fail but we must not return an error. Instead
			// we return the ciphertext as it is.
			return b, kms.AES256
		}

		b = b[:0]

```
read EC key
writing EC key
```

Alternatively, use the following command to generate a private ECDSA key protected by a password:

```sh
openssl ecparam -genkey -name prime256v1 | openssl ec -aes256 -out private.key -passout pass:PASSWORD
```

#### 3.2.2 Generate a private key with RSA

Use the following command to generate a private key with RSA:

```sh
openssl genrsa -out private.key 2048
```

                                  ExtraArgs={'ServerSideEncryption': 'AES256'})

# Upload with server side encryption, using temporary credentials
s3.meta.client.upload_file('/etc/hosts',
                           'testbucket',
                           'hosts',
                           ExtraArgs={'ServerSideEncryption': 'AES256'})

# Download encrypted object using temporary credentials

	{URL: &url.URL{}, Header: http.Header{xhttp.AmzServerSideEncryptionCustomerAlgorithm: []string{"AES256"}}, IsTLS: false, ShouldFail: true}, // 1
	{URL: &url.URL{}, Header: http.Header{xhttp.AmzServerSideEncryptionCustomerAlgorithm: []string{"AES256"}}, IsTLS: true, ShouldFail: false}, // 2

```

`--sftp=cipher-algos=...` specifies the allowed cipher algorithms. 
If unspecified then a sensible default is used.

Valid values: 
```
aes128-ctr
aes192-ctr
aes256-ctr
******@****.***
aes256******@****.***
******@****.***
arcfour256
arcfour128
arcfour
aes128-cbc
3des-cbc
```