Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)   
Deprecated in [API level 23](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Ctors](https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#pubctors) \| [Methods](https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#inhmethods)

# KeyPairGeneratorSpec.Builder

*** ** * ** ***

` public static final class KeyPairGeneratorSpec.Builder `   
` extends https://developer.android.com/reference/java/lang/Object ` ` `

|---|---|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||
| ↳ | android.security.KeyPairGeneratorSpec.Builder |

<br />

*** ** * ** ***

<br />

**This class was deprecated in API level 23.**   

Use `https://developer.android.com/reference/android/security/keystore/KeyGenParameterSpec.Builder` instead.

Builder class for `https://developer.android.com/reference/android/security/KeyPairGeneratorSpec` objects.

This will build a parameter spec for use with the [Android KeyStore facility](https://developer.android.com/training/articles/keystore).

The required fields must be filled in with the builder.

Example:

```
Calendar start = Calendar.getInstance();
Calendar end = Calendar.getInstance();
end.add(Calendar.YEAR, 1);

KeyPairGeneratorSpec spec =
        new KeyPairGeneratorSpec.Builder(mContext).setAlias("myKey")
                .setSubject(new X500Principal("CN=myKey")).setSerialNumber(BigInteger.valueOf(1337))
                .setStartDate(start.getTime()).setEndDate(end.getTime()).build();
```

<br />

## Summary

| ### Public constructors ||
|---|---|
| ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#Builder(android.content.Context)(https://developer.android.com/reference/android/content/Context context) ` Creates a new instance of the `Builder` with the given `context`. |

| ### Public methods ||
|---|---|
| ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec` | ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#build()() ` Builds the instance of the `KeyPairGeneratorSpec`. |
| ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#setAlgorithmParameterSpec(java.security.spec.AlgorithmParameterSpec)(https://developer.android.com/reference/java/security/spec/AlgorithmParameterSpec spec) ` Sets the algorithm-specific key generation parameters. |
| ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#setAlias(java.lang.String)(https://developer.android.com/reference/java/lang/String alias) ` Sets the alias to be used to retrieve the key later from a `https://developer.android.com/reference/java/security/KeyStore` instance using the `AndroidKeyStore` provider. |
| ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#setEncryptionRequired()() ` *This method is deprecated. Data at rest encryption is enabled by default. If extra binding to the lockscreen credential is desired, use `https://developer.android.com/reference/android/security/keystore/KeyGenParameterSpec.Builder#setUserAuthenticationRequired(boolean)`. This flag will be ignored from Android S.* |
| ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#setEndDate(java.util.Date)(https://developer.android.com/reference/java/util/Date endDate) ` Sets the end of the validity period for the self-signed certificate of the generated key pair. |
| ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#setKeySize(int)(int keySize) ` Sets the key size for the keypair to be created. |
| ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#setKeyType(java.lang.String)(https://developer.android.com/reference/java/lang/String keyType) ` Sets the type of key pair to be generated. |
| ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#setSerialNumber(java.math.BigInteger)(https://developer.android.com/reference/java/math/BigInteger serialNumber) ` Sets the serial number used for the self-signed certificate of the generated key pair. |
| ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#setStartDate(java.util.Date)(https://developer.android.com/reference/java/util/Date startDate) ` Sets the start of the validity period for the self-signed certificate of the generated key pair. |
| ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | ` https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder#setSubject(javax.security.auth.x500.X500Principal)(https://developer.android.com/reference/javax/security/auth/x500/X500Principal subject) ` Sets the subject used for the self-signed certificate of the generated key pair. |

### Inherited methods

From class ` https://developer.android.com/reference/java/lang/Object ` ` https://developer.android.com/reference/java/lang/Object` ` https://developer.android.com/reference/java/lang/Object#clone()() `

Creates and returns a copy of this object.
` boolean` ` https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object obj) `

Indicates whether some other object is "equal to" this one.
` void` ` https://developer.android.com/reference/java/lang/Object#finalize()() `

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
` final https://developer.android.com/reference/java/lang/Class<?>` ` https://developer.android.com/reference/java/lang/Object#getClass()() `

Returns the runtime class of this `Object`.
` int` ` https://developer.android.com/reference/java/lang/Object#hashCode()() `

Returns a hash code value for the object.
` final void` ` https://developer.android.com/reference/java/lang/Object#notify()() `

Wakes up a single thread that is waiting on this object's monitor.
` final void` ` https://developer.android.com/reference/java/lang/Object#notifyAll()() `

Wakes up all threads that are waiting on this object's monitor.
` https://developer.android.com/reference/java/lang/String` ` https://developer.android.com/reference/java/lang/Object#toString()() `

Returns a string representation of the object.
` final void` ` https://developer.android.com/reference/java/lang/Object#wait(long,%20int)(long timeoutMillis, int nanos) `

Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed.
` final void` ` https://developer.android.com/reference/java/lang/Object#wait(long)(long timeoutMillis) `

Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed.
` final void` ` https://developer.android.com/reference/java/lang/Object#wait()() `

Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*.

## Public constructors

### Builder

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public Builder (Context context)
```

Creates a new instance of the `Builder` with the given `context`. The `context` passed in may be used to pop up some UI to ask the user to unlock or initialize the Android KeyStore facility.

<br />

| Parameters ||
|---|---|
| `context` | `Context`: This value cannot be `null`. <br /> |

## Public methods

### build

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public KeyPairGeneratorSpec build ()
```

Builds the instance of the `KeyPairGeneratorSpec`.

<br />

| Returns ||
|---|---|
| `https://developer.android.com/reference/android/security/KeyPairGeneratorSpec` | built instance of `KeyPairGeneratorSpec` This value cannot be `null`. <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if a required field is missing |

### setAlgorithmParameterSpec

Added in [API level 19](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)   
Deprecated in [API level 23](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public KeyPairGeneratorSpec.Builder setAlgorithmParameterSpec (AlgorithmParameterSpec spec)
```

Sets the algorithm-specific key generation parameters. For example, for RSA keys this may be an instance of `https://developer.android.com/reference/java/security/spec/RSAKeyGenParameterSpec`.

<br />

| Parameters ||
|---|---|
| `spec` | `AlgorithmParameterSpec`: This value cannot be `null`. <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | <br /> |

### setAlias

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public KeyPairGeneratorSpec.Builder setAlias (String alias)
```

Sets the alias to be used to retrieve the key later from a `https://developer.android.com/reference/java/security/KeyStore` instance using the `AndroidKeyStore` provider.

<br />

| Parameters ||
|---|---|
| `alias` | `String`: This value cannot be `null`. <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | This value cannot be `null`. <br /> |

### setEncryptionRequired

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public KeyPairGeneratorSpec.Builder setEncryptionRequired ()
```

<br />

**This method is deprecated.**   

Data at rest encryption is enabled by default. If extra binding to the lockscreen credential is desired, use `https://developer.android.com/reference/android/security/keystore/KeyGenParameterSpec.Builder#setUserAuthenticationRequired(boolean)`. This flag will be ignored from Android S.

Indicates that this key pair must be encrypted at rest. This will protect the key pair with the secure lock screen credential (e.g., password, PIN, or pattern).

Note that this feature requires that the secure lock screen (e.g., password, PIN, pattern) is set up, otherwise key pair generation will fail. Moreover, this key pair will be deleted when the secure lock screen is disabled or reset (e.g., by the user or a Device Administrator). Finally, this key pair cannot be used until the user unlocks the secure lock screen after boot.

<br />

| Returns ||
|---|---|
| `https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | This value cannot be `null`. <br /> |

**See also:**

- `https://developer.android.com/reference/android/app/KeyguardManager#isDeviceSecure()`

### setEndDate

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public KeyPairGeneratorSpec.Builder setEndDate (Date endDate)
```

Sets the end of the validity period for the self-signed certificate of the generated key pair.

<br />

| Parameters ||
|---|---|
| `endDate` | `Date`: This value cannot be `null`. <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | This value cannot be `null`. <br /> |

### setKeySize

Added in [API level 19](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)   
Deprecated in [API level 23](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public KeyPairGeneratorSpec.Builder setKeySize (int keySize)
```

Sets the key size for the keypair to be created. For instance, for a key type of RSA this will set the modulus size and for a key type of EC it will select a curve with a matching field size. If this method is called for ML-DSA, the provided value will be ignored.

<br />

| Parameters ||
|---|---|
| `keySize` | `int` <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | This value cannot be `null`. <br /> |

### setKeyType

Added in [API level 19](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)   
Deprecated in [API level 23](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public KeyPairGeneratorSpec.Builder setKeyType (String keyType)
```

Sets the type of key pair to be generated. See the `KEY_ALGORITHM_<name>` constants in `https://developer.android.com/reference/android/security/keystore/KeyProperties` for the supported values.

<br />

| Parameters ||
|---|---|
| `keyType` | `String`: This value cannot be `null`. <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | This value cannot be `null`. <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/security/NoSuchAlgorithmException` |   |

### setSerialNumber

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public KeyPairGeneratorSpec.Builder setSerialNumber (BigInteger serialNumber)
```

Sets the serial number used for the self-signed certificate of the generated key pair.

<br />

| Parameters ||
|---|---|
| `serialNumber` | `BigInteger`: This value cannot be `null`. <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | This value cannot be `null`. <br /> |

### setStartDate

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public KeyPairGeneratorSpec.Builder setStartDate (Date startDate)
```

Sets the start of the validity period for the self-signed certificate of the generated key pair.

<br />

| Parameters ||
|---|---|
| `startDate` | `Date`: This value cannot be `null`. <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | This value cannot be `null`. <br /> |

### setSubject

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public KeyPairGeneratorSpec.Builder setSubject (X500Principal subject)
```

Sets the subject used for the self-signed certificate of the generated key pair.

<br />

| Parameters ||
|---|---|
| `subject` | `X500Principal`: This value cannot be `null`. <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/android/security/KeyPairGeneratorSpec.Builder` | This value cannot be `null`. <br /> |