Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Inherited Constants](https://developer.android.com/reference/java/security/interfaces/XECPrivateKey#inhconstants) \| [Methods](https://developer.android.com/reference/java/security/interfaces/XECPrivateKey#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/java/security/interfaces/XECPrivateKey#inhmethods)

# XECPrivateKey


`
public


interface
XECPrivateKey
`


`


implements

https://developer.android.com/reference/java/security/PrivateKey,

https://developer.android.com/reference/java/security/interfaces/XECKey


`

|---|
| java.security.interfaces.XECPrivateKey |

<br />

*** ** * ** ***

An interface for an elliptic curve private key as defined by RFC 7748.
These keys are distinct from the keys represented by `ECPrivateKey`,
and they are intended for use with algorithms based on RFC 7748 such as the
XDH `KeyAgreement` algorithm.

An XEC private key is an encoded scalar value as described in RFC 7748.
The decoding procedure defined in this RFC includes an operation that forces
certain bits of the key to either 1 or 0. This operation is known as
"pruning" or "clamping" the private key. Arrays returned by this interface
are unpruned, and implementations will need to prune the array before
using it in any numerical operations.

## Summary

| ### Inherited constants |
|---|
| From interface `https://developer.android.com/reference/java/security/PrivateKey` |---|---| | `long` | `https://developer.android.com/reference/java/security/PrivateKey#serialVersionUID` *This constant was deprecated in API level 34. A `serialVersionUID` field in an interface is ineffectual. Do not use; no replacement.* | |
| From interface `https://developer.android.com/reference/java/security/Key` |---|---| | `long` | `https://developer.android.com/reference/java/security/Key#serialVersionUID` *This constant was deprecated in API level 34. A `serialVersionUID` field in an interface is ineffectual. Do not use; no replacement.* | |

| ### Public methods ||
|---|---|
| ` abstract https://developer.android.com/reference/java/util/Optional<byte[]>` | ` https://developer.android.com/reference/java/security/interfaces/XECPrivateKey#getScalar()() ` Get the scalar value encoded as an unpruned byte array. |

| ### Inherited methods |
|---|---|
| From interface ` https://developer.android.com/reference/java/security/interfaces/XECKey ` |---|---| | ` abstract https://developer.android.com/reference/java/security/spec/AlgorithmParameterSpec` | ` https://developer.android.com/reference/java/security/interfaces/XECKey#getParams()() ` Returns the algorithm parameters associated with the key. | ||
| From interface ` https://developer.android.com/reference/javax/security/auth/Destroyable ` |---|---| | ` default void` | ` https://developer.android.com/reference/javax/security/auth/Destroyable#destroy()() ` Destroy this `Object`. | | ` default boolean` | ` https://developer.android.com/reference/javax/security/auth/Destroyable#isDestroyed()() ` Determine if this `Object` has been destroyed. | ||
| From interface ` https://developer.android.com/reference/java/security/Key ` |---|---| | ` abstract https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/security/Key#getAlgorithm()() ` Returns the standard algorithm name for this key. | | ` abstract byte[]` | ` https://developer.android.com/reference/java/security/Key#getEncoded()() ` Returns the key in its primary encoding format, or null if this key does not support encoding. | | ` abstract https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/security/Key#getFormat()() ` Returns the name of the primary encoding format of this key, or null if this key does not support encoding. | ||

## Public methods

### getScalar

Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract Optional<byte[]> getScalar ()
```

Get the scalar value encoded as an unpruned byte array. A new copy of
the array is returned each time this method is called.

<br />

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/Optional<byte[]>` | the unpruned encoded scalar value, or an empty Optional if the scalar cannot be extracted (e.g. if the provider is a hardware token and the private key is not allowed to leave the crypto boundary). <br /> |