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KeyFactorySpi
abstract class KeyFactorySpi
This class defines the Service Provider Interface (SPI) for the KeyFactory class. All the abstract methods in this class must be implemented by each cryptographic service provider who wishes to supply the implementation of a key factory for a particular algorithm.
Key factories are used to convert keys (opaque cryptographic keys of type Key) into key specifications (transparent representations of the underlying key material), and vice versa.
Key factories are bi-directional. That is, they allow you to build an opaque key object from a given key specification (key material), or to retrieve the underlying key material of a key object in a suitable format.
Multiple compatible key specifications may exist for the same key. For example, a DSA public key may be specified using DSAPublicKeySpec or X509EncodedKeySpec. A key factory can be used to translate between compatible key specifications.
A provider should document all the key specifications supported by its key factory.
Summary
| Protected methods |
| abstract PrivateKey! |
Generates a private key object from the provided key specification (key material).
|
| abstract PublicKey! |
Generates a public key object from the provided key specification (key material).
|
| abstract T |
Returns a specification (key material) of the given key object.
|
| abstract Key! |
Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this key factory.
|
Public constructors
KeyFactorySpi
KeyFactorySpi()
Protected methods
engineGeneratePrivate
protected abstract fun engineGeneratePrivate(keySpec: KeySpec!): PrivateKey!
Generates a private key object from the provided key specification (key material).
| Parameters |
keySpec |
KeySpec!: the specification (key material) of the private key. |
| Exceptions |
java.security.spec.InvalidKeySpecException |
if the given key specification is inappropriate for this key factory to produce a private key. |
engineGeneratePublic
protected abstract fun engineGeneratePublic(keySpec: KeySpec!): PublicKey!
Generates a public key object from the provided key specification (key material).
| Parameters |
keySpec |
KeySpec!: the specification (key material) of the public key. |
| Exceptions |
java.security.spec.InvalidKeySpecException |
if the given key specification is inappropriate for this key factory to produce a public key. |
engineGetKeySpec
protected abstract fun <T : KeySpec!> engineGetKeySpec(
key: Key!,
keySpec: Class<T>!
): T
Returns a specification (key material) of the given key object. keySpec identifies the specification class in which the key material should be returned. It could, for example, be DSAPublicKeySpec.class, to indicate that the key material should be returned in an instance of the DSAPublicKeySpec class.
| Parameters |
<T> |
the type of the key specification to be returned |
key |
Key!: the key. |
keySpec |
Class<T>!: the specification class in which the key material should be returned. |
| Return |
T |
the underlying key specification (key material) in an instance of the requested specification class. |
| Exceptions |
java.security.spec.InvalidKeySpecException |
if the requested key specification is inappropriate for the given key, or the given key cannot be dealt with (e.g., the given key has an unrecognized format). |
engineTranslateKey
protected abstract fun engineTranslateKey(key: Key!): Key!
Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this key factory.
| Parameters |
key |
Key!: the key whose provider is unknown or untrusted. |
| Return |
Key! |
the translated key. |
| Exceptions |
java.security.InvalidKeyException |
if the given key cannot be processed by this key factory. |
Content and code samples on this page are subject to the licenses described in the Content License. Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
Last updated 2025-02-10 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-02-10 UTC."],[],[],null,["# KeyFactorySpi\n\nAdded in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)\n\nKeyFactorySpi\n=============\n\n```\nabstract class KeyFactorySpi\n```\n\n|---|----------------------------------|\n| [kotlin.Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html) ||\n| ↳ | [java.security.KeyFactorySpi](#) |\n\nThis class defines the *Service Provider Interface* (**SPI** ) for the `KeyFactory` class. All the abstract methods in this class must be implemented by each cryptographic service provider who wishes to supply the implementation of a key factory for a particular algorithm.\n\nKey factories are used to convert *keys* (opaque cryptographic keys of type `Key`) into *key specifications* (transparent representations of the underlying key material), and vice versa.\n\nKey factories are bi-directional. That is, they allow you to build an opaque key object from a given key specification (key material), or to retrieve the underlying key material of a key object in a suitable format.\n\nMultiple compatible key specifications may exist for the same key. For example, a DSA public key may be specified using `DSAPublicKeySpec` or `X509EncodedKeySpec`. A key factory can be used to translate between compatible key specifications.\n\nA provider should document all the key specifications supported by its key factory.\n\nSummary\n-------\n\n| Public constructors ||\n|----------------------------------------------|---|\n| [KeyFactorySpi](#KeyFactorySpi())`()` \u003cbr /\u003e |\n\n| Protected methods ||\n|--------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| abstract [PrivateKey](/reference/kotlin/java/security/PrivateKey)! | [engineGeneratePrivate](#engineGeneratePrivate(java.security.spec.KeySpec))`(`keySpec:` `[KeySpec](/reference/kotlin/java/security/spec/KeySpec)!`)` Generates a private key object from the provided key specification (key material). |\n| abstract [PublicKey](/reference/kotlin/java/security/PublicKey)! | [engineGeneratePublic](#engineGeneratePublic(java.security.spec.KeySpec))`(`keySpec:` `[KeySpec](/reference/kotlin/java/security/spec/KeySpec)!`)` Generates a public key object from the provided key specification (key material). |\n| abstract T | [engineGetKeySpec](#engineGetKeySpec(java.security.Key,%20java.lang.Class))`(`key:` `[Key](/reference/kotlin/java/security/Key)!`, `keySpec:` `[Class](../lang/Class.html#)\u003cT\u003e!`)` Returns a specification (key material) of the given key object. |\n| abstract [Key](/reference/kotlin/java/security/Key)! | [engineTranslateKey](#engineTranslateKey(java.security.Key))`(`key:` `[Key](/reference/kotlin/java/security/Key)!`)` Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this key factory. |\n\nPublic constructors\n-------------------\n\n### KeyFactorySpi\n\nAdded in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) \n\n```\nKeyFactorySpi()\n```\n\nProtected methods\n-----------------\n\n### engineGeneratePrivate\n\nAdded in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) \n\n```\nprotected abstract fun engineGeneratePrivate(keySpec: KeySpec!): PrivateKey!\n```\n\nGenerates a private key object from the provided key specification (key material).\n\n| Parameters ||\n|-----------|----------------------------------------------------------------------------------------------------------------|\n| `keySpec` | [KeySpec](/reference/kotlin/java/security/spec/KeySpec)!: the specification (key material) of the private key. |\n\n| Return ||\n|-----------------------------------------------------------|------------------|\n| [PrivateKey](/reference/kotlin/java/security/PrivateKey)! | the private key. |\n\n| Exceptions ||\n|----------------------------------------------|------------------------------------------------------------------------------------------------|\n| `java.security.spec.InvalidKeySpecException` | if the given key specification is inappropriate for this key factory to produce a private key. |\n\n### engineGeneratePublic\n\nAdded in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) \n\n```\nprotected abstract fun engineGeneratePublic(keySpec: KeySpec!): PublicKey!\n```\n\nGenerates a public key object from the provided key specification (key material).\n\n| Parameters ||\n|-----------|---------------------------------------------------------------------------------------------------------------|\n| `keySpec` | [KeySpec](/reference/kotlin/java/security/spec/KeySpec)!: the specification (key material) of the public key. |\n\n| Return ||\n|---------------------------------------------------------|-----------------|\n| [PublicKey](/reference/kotlin/java/security/PublicKey)! | the public key. |\n\n| Exceptions ||\n|----------------------------------------------|-----------------------------------------------------------------------------------------------|\n| `java.security.spec.InvalidKeySpecException` | if the given key specification is inappropriate for this key factory to produce a public key. |\n\n### engineGetKeySpec\n\nAdded in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) \n\n```\nprotected abstract fun \u003cT : KeySpec!\u003e engineGetKeySpec(\n key: Key!, \n keySpec: Class\u003cT\u003e!\n): T\n```\n\nReturns a specification (key material) of the given key object. `keySpec` identifies the specification class in which the key material should be returned. It could, for example, be `DSAPublicKeySpec.class`, to indicate that the key material should be returned in an instance of the `DSAPublicKeySpec` class.\n\n| Parameters ||\n|-----------|-----------------------------------------------------------------------------------------------------------|\n| `\u003cT\u003e` | the type of the key specification to be returned |\n| `key` | [Key](/reference/kotlin/java/security/Key)!: the key. |\n| `keySpec` | [Class](../lang/Class.html#)\\\u003cT\\\u003e!: the specification class in which the key material should be returned. |\n\n| Return ||\n|---|------------------------------------------------------------------------------------------------------|\n| T | the underlying key specification (key material) in an instance of the requested specification class. |\n\n| Exceptions ||\n|----------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| `java.security.spec.InvalidKeySpecException` | if the requested key specification is inappropriate for the given key, or the given key cannot be dealt with (e.g., the given key has an unrecognized format). |\n\n### engineTranslateKey\n\nAdded in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) \n\n```\nprotected abstract fun engineTranslateKey(key: Key!): Key!\n```\n\nTranslates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this key factory.\n\n| Parameters ||\n|-------|----------------------------------------------------------------------------------------------|\n| `key` | [Key](/reference/kotlin/java/security/Key)!: the key whose provider is unknown or untrusted. |\n\n| Return ||\n|---------------------------------------------|---------------------|\n| [Key](/reference/kotlin/java/security/Key)! | the translated key. |\n\n| Exceptions ||\n|-------------------------------------|-----------------------------------------------------------|\n| `java.security.InvalidKeyException` | if the given key cannot be processed by this key factory. |"]]
