# KeyAgreement

public class **KeyAgreement** extends [Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html)  
This class provides the functionality of a key agreement (or key
exchange) protocol.


The keys involved in establishing a shared secret are created by one of the
key generators (`KeyPairGenerator` or
`KeyGenerator`), a `KeyFactory`, or as a result from
an intermediate phase of the key agreement protocol.

For each of the correspondents in the key exchange, `doPhase`
needs to be called. For example, if this key exchange is with one other
party, `doPhase` needs to be called once, with the
`lastPhase` flag set to `true`.
If this key exchange is
with two other parties, `doPhase` needs to be called twice,
the first time setting the `lastPhase` flag to
`false`, and the second time setting it to `true`.
There may be any number of parties involved in a key exchange.

Android provides the following `KeyAgreement` algorithms:

| Algorithm | Supported API Levels |
|---|---|
| DH | 1+ |
| ECDH | 11+ |

This algorithm is described in the [KeyAgreement section](https://developers.google.com/j2objc/javadoc/jre/technotes/guides/security/StandardNames.html#KeyAgreement) of the Java Cryptography Architecture Standard Algorithm Name Documentation.

<br />

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyGenerator.html`
- `https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/SecretKey.html`

### Protected Constructor Summary

|---|---|
|   | [KeyAgreement](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#KeyAgreement(javax.crypto.KeyAgreementSpi,%20java.security.Provider,%20java.lang.String))([KeyAgreementSpi](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreementSpi.html) keyAgreeSpi, [Provider](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Provider.html) provider, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) algorithm) Creates a KeyAgreement object. |

### Public Method Summary

|---|---|
| final [Key](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Key.html) | [doPhase](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#doPhase(java.security.Key,%20boolean))([Key](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Key.html) key, boolean lastPhase) Executes the next phase of this key agreement with the given key that was received from one of the other parties involved in this key agreement. |
| final byte\[\] | [generateSecret](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#generateSecret())() Generates the shared secret and returns it in a new buffer. |
| final int | [generateSecret](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#generateSecret(byte[],%20int))(byte\[\] sharedSecret, int offset) Generates the shared secret, and places it into the buffer `sharedSecret`, beginning at `offset` inclusive. |
| final [SecretKey](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/SecretKey.html) | [generateSecret](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#generateSecret(java.lang.String))([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) algorithm) Creates the shared secret and returns it as a `SecretKey` object of the specified algorithm. |
| final [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) | [getAlgorithm](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#getAlgorithm())() Returns the algorithm name of this `KeyAgreement` object. |
| final static [KeyAgreement](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html) | [getInstance](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#getInstance(java.lang.String))([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) algorithm) Returns a `KeyAgreement` object that implements the specified key agreement algorithm. |
| final static [KeyAgreement](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html) | [getInstance](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#getInstance(java.lang.String,%20java.lang.String))([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) algorithm, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) provider) Returns a `KeyAgreement` object that implements the specified key agreement algorithm. |
| final static [KeyAgreement](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html) | [getInstance](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#getInstance(java.lang.String,%20java.security.Provider))([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) algorithm, [Provider](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Provider.html) provider) Returns a `KeyAgreement` object that implements the specified key agreement algorithm. |
| final [Provider](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Provider.html) | [getProvider](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#getProvider())() Returns the provider of this `KeyAgreement` object. |
| final void | [init](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#init(java.security.Key,%20java.security.spec.AlgorithmParameterSpec))([Key](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Key.html) key, [AlgorithmParameterSpec](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/spec/AlgorithmParameterSpec.html) params) Initializes this key agreement with the given key and set of algorithm parameters. |
| final void | [init](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#init(java.security.Key,%20java.security.spec.AlgorithmParameterSpec,%20java.security.SecureRandom))([Key](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Key.html) key, [AlgorithmParameterSpec](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/spec/AlgorithmParameterSpec.html) params, [SecureRandom](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/SecureRandom.html) random) Initializes this key agreement with the given key, set of algorithm parameters, and source of randomness. |
| final void | [init](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#init(java.security.Key,%20java.security.SecureRandom))([Key](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Key.html) key, [SecureRandom](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/SecureRandom.html) random) Initializes this key agreement with the given key and source of randomness. |
| final void | [init](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html#init(java.security.Key))([Key](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Key.html) key) Initializes this key agreement with the given key, which is required to contain all the algorithm parameters required for this key agreement. |

### Inherited Method Summary

From class [java.lang.Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html)

|---|---|
| [Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html) | [clone](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#clone())() Creates and returns a copy of this `Object`. |
| boolean | [equals](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#equals(java.lang.Object))([Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html) obj) Compares this instance with the specified object and indicates if they are equal. |
| void | [finalize](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#finalize())() Invoked when the garbage collector has detected that this instance is no longer reachable. |
| final [Class](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Class.html)\<?\> | [getClass](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#getClass())() Returns the unique instance of `https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Class.html` that represents this object's class. |
| int | [hashCode](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#hashCode())() Returns an integer hash code for this object. |
| final void | [notify](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#notify())() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up. |
| final void | [notifyAll](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#notifyAll())() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up. |
| [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) | [toString](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#toString())() Returns a string containing a concise, human-readable description of this object. |
| final void | [wait](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#wait(long,%20int))(long timeout, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires. |
| final void | [wait](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#wait(long))(long timeout) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires. |
| final void | [wait](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#wait())() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object. |

## Protected Constructors

#### protected
**KeyAgreement**
([KeyAgreementSpi](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreementSpi.html) keyAgreeSpi, [Provider](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Provider.html) provider, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) algorithm)

Creates a KeyAgreement object.

##### Parameters

| keyAgreeSpi | the delegate |
| provider | the provider |
| algorithm | the algorithm |
|---|---|

## Public Methods

#### public final [Key](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Key.html)
**doPhase**
([Key](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Key.html) key, boolean lastPhase)

Executes the next phase of this key agreement with the given
key that was received from one of the other parties involved in this key
agreement.

##### Parameters

| key | the key for this phase. For example, in the case of Diffie-Hellman between 2 parties, this would be the other party's Diffie-Hellman public key. |
| lastPhase | flag which indicates whether or not this is the last phase of this key agreement. |
|---|---|

##### Returns

- the (intermediate) key resulting from this phase, or null if this phase does not yield a key

##### Throws

| [InvalidKeyException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/InvalidKeyException.html) | if the given key is inappropriate for this phase. |
| [IllegalStateException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalStateException.html) | if this key agreement has not been initialized. |
|---|---|

#### public final byte\[\]
**generateSecret**
()

Generates the shared secret and returns it in a new buffer.

This method resets this `KeyAgreement` object, so that it
can be reused for further key agreements. Unless this key agreement is
reinitialized with one of the `init` methods, the same
private information and algorithm parameters will be used for
subsequent key agreements.

##### Returns

- the new buffer with the shared secret

##### Throws

| [IllegalStateException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalStateException.html) | if this key agreement has not been completed yet |
|---|---|

#### public final int
**generateSecret**
(byte\[\] sharedSecret, int offset)

Generates the shared secret, and places it into the buffer
`sharedSecret`, beginning at `offset` inclusive.

If the `sharedSecret` buffer is too small to hold the
result, a `ShortBufferException` is thrown.
In this case, this call should be repeated with a larger output buffer.

This method resets this `KeyAgreement` object, so that it
can be reused for further key agreements. Unless this key agreement is
reinitialized with one of the `init` methods, the same
private information and algorithm parameters will be used for
subsequent key agreements.

##### Parameters

| sharedSecret | the buffer for the shared secret |
| offset | the offset in `sharedSecret` where the shared secret will be stored |
|---|---|

##### Returns

- the number of bytes placed into `sharedSecret`

##### Throws

| [IllegalStateException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalStateException.html) | if this key agreement has not been completed yet |
| [ShortBufferException](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/ShortBufferException.html) | if the given output buffer is too small to hold the secret |
|---|---|

#### public final [SecretKey](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/SecretKey.html)
**generateSecret**
([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) algorithm)

Creates the shared secret and returns it as a `SecretKey`
object of the specified algorithm.

This method resets this `KeyAgreement` object, so that it
can be reused for further key agreements. Unless this key agreement is
reinitialized with one of the `init` methods, the same
private information and algorithm parameters will be used for
subsequent key agreements.

##### Parameters

| algorithm | the requested secret-key algorithm |
|---|---|

##### Returns

- the shared secret key

##### Throws

| [IllegalStateException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalStateException.html) | if this key agreement has not been completed yet |
| [NoSuchAlgorithmException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/NoSuchAlgorithmException.html) | if the specified secret-key algorithm is not available |
| [InvalidKeyException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/InvalidKeyException.html) | if the shared secret-key material cannot be used to generate a secret key of the specified algorithm (e.g., the key material is too short) |
|---|---|

#### public final [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html)
**getAlgorithm**
()

Returns the algorithm name of this `KeyAgreement` object.

This is the same name that was specified in one of the
`getInstance` calls that created this
`KeyAgreement` object.

##### Returns

- the algorithm name of this `KeyAgreement` object.

#### public static final [KeyAgreement](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html)
**getInstance**
([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) algorithm)

Returns a `KeyAgreement` object that implements the
specified key agreement algorithm.

This method traverses the list of registered security Providers,
starting with the most preferred Provider.
A new KeyAgreement object encapsulating the
KeyAgreementSpi implementation from the first
Provider that supports the specified algorithm is returned.

Note that the list of registered providers may be retrieved via
the `https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Security.html#getProviders()` method.

##### Parameters

| algorithm | the standard name of the requested key agreement algorithm. See the KeyAgreement section in the [Java Cryptography Architecture Standard Algorithm Name Documentation](https://developers.google.com/j2objc/javadoc/jre/technotes/guides/security/StandardNames.html#KeyAgreement) for information about standard algorithm names. |
|---|---|

##### Returns

- the new `KeyAgreement` object.

##### Throws

| [NullPointerException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/NullPointerException.html) | if the specified algorithm is null. |
| [NoSuchAlgorithmException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/NoSuchAlgorithmException.html) | if no Provider supports a KeyAgreementSpi implementation for the specified algorithm. |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Provider.html`

#### public static final [KeyAgreement](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html)
**getInstance**
([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) algorithm, [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) provider)

Returns a `KeyAgreement` object that implements the
specified key agreement algorithm.

A new KeyAgreement object encapsulating the
KeyAgreementSpi implementation from the specified provider
is returned. The specified provider must be registered
in the security provider list.

Note that the list of registered providers may be retrieved via
the `https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Security.html#getProviders()` method.

##### Parameters

| algorithm | the standard name of the requested key agreement algorithm. See the KeyAgreement section in the [Java Cryptography Architecture Standard Algorithm Name Documentation](https://developers.google.com/j2objc/javadoc/jre/technotes/guides/security/StandardNames.html#KeyAgreement) for information about standard algorithm names. |
| provider | the name of the provider. |
|---|---|

##### Returns

- the new `KeyAgreement` object.

##### Throws

| [NullPointerException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/NullPointerException.html) | if the specified algorithm is null. |
| [NoSuchAlgorithmException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/NoSuchAlgorithmException.html) | if a KeyAgreementSpi implementation for the specified algorithm is not available from the specified provider. |
| [NoSuchProviderException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/NoSuchProviderException.html) | if the specified provider is not registered in the security provider list. |
| [IllegalArgumentException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalArgumentException.html) | if the `provider` is null or empty. |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Provider.html`

#### public static final [KeyAgreement](https://developers.google.com/j2objc/javadoc/jre/reference/javax/crypto/KeyAgreement.html)
**getInstance**
([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) algorithm, [Provider](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Provider.html) provider)

Returns a `KeyAgreement` object that implements the
specified key agreement algorithm.

A new KeyAgreement object encapsulating the
KeyAgreementSpi implementation from the specified Provider
object is returned. Note that the specified Provider object
does not have to be registered in the provider list.

##### Parameters

| algorithm | the standard name of the requested key agreement algorithm. See the KeyAgreement section in the [Java Cryptography Architecture Standard Algorithm Name Documentation](https://developers.google.com/j2objc/javadoc/jre/technotes/guides/security/StandardNames.html#KeyAgreement) for information about standard algorithm names. |
| provider | the provider. |
|---|---|

##### Returns

- the new `KeyAgreement` object.

##### Throws

| [NullPointerException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/NullPointerException.html) | if the specified algorithm is null. |
| [NoSuchAlgorithmException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/NoSuchAlgorithmException.html) | if a KeyAgreementSpi implementation for the specified algorithm is not available from the specified Provider object. |
| [IllegalArgumentException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalArgumentException.html) | if the `provider` is null. |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Provider.html`

#### public final [Provider](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Provider.html)
**getProvider**
()

Returns the provider of this `KeyAgreement` object.

##### Returns

- the provider of this `KeyAgreement` object

#### public final void
**init**
([Key](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Key.html) key, [AlgorithmParameterSpec](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/spec/AlgorithmParameterSpec.html) params)

Initializes this key agreement with the given key and set of
algorithm parameters.

If this key agreement requires any random bytes, it will get
them using the
`https://developers.google.com/j2objc/javadoc/jre/reference/java/security/SecureRandom.html`
implementation of the highest-priority
installed provider as the source of randomness.
(If none of the installed providers supply an implementation of
SecureRandom, a system-provided source of randomness will be used.)

##### Parameters

| key | the party's private information. For example, in the case of the Diffie-Hellman key agreement, this would be the party's own Diffie-Hellman private key. |
| params | the key agreement parameters |
|---|---|

##### Throws

| [InvalidKeyException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/InvalidKeyException.html) | if the given key is inappropriate for this key agreement, e.g., is of the wrong type or has an incompatible algorithm type. |
| [InvalidAlgorithmParameterException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/InvalidAlgorithmParameterException.html) | if the given parameters are inappropriate for this key agreement. |
|---|---|

#### public final void
**init**
([Key](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Key.html) key, [AlgorithmParameterSpec](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/spec/AlgorithmParameterSpec.html) params, [SecureRandom](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/SecureRandom.html) random)

Initializes this key agreement with the given key, set of
algorithm parameters, and source of randomness.

##### Parameters

| key | the party's private information. For example, in the case of the Diffie-Hellman key agreement, this would be the party's own Diffie-Hellman private key. |
| params | the key agreement parameters |
| random | the source of randomness |
|---|---|

##### Throws

| [InvalidKeyException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/InvalidKeyException.html) | if the given key is inappropriate for this key agreement, e.g., is of the wrong type or has an incompatible algorithm type. |
| [InvalidAlgorithmParameterException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/InvalidAlgorithmParameterException.html) | if the given parameters are inappropriate for this key agreement. |
|---|---|

#### public final void
**init**
([Key](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Key.html) key, [SecureRandom](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/SecureRandom.html) random)

Initializes this key agreement with the given key and source of
randomness. The given key is required to contain all the algorithm
parameters required for this key agreement.

If the key agreement algorithm requires random bytes, it gets them
from the given source of randomness, `random`.
However, if the underlying
algorithm implementation does not require any random bytes,
`random` is ignored.

##### Parameters

| key | the party's private information. For example, in the case of the Diffie-Hellman key agreement, this would be the party's own Diffie-Hellman private key. |
| random | the source of randomness |
|---|---|

##### Throws

| [InvalidKeyException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/InvalidKeyException.html) | if the given key is inappropriate for this key agreement, e.g., is of the wrong type or has an incompatible algorithm type. |
|---|---|

#### public final void
**init**
([Key](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/Key.html) key)

Initializes this key agreement with the given key, which is required to
contain all the algorithm parameters required for this key agreement.

If this key agreement requires any random bytes, it will get
them using the
`https://developers.google.com/j2objc/javadoc/jre/reference/java/security/SecureRandom.html`
implementation of the highest-priority
installed provider as the source of randomness.
(If none of the installed providers supply an implementation of
SecureRandom, a system-provided source of randomness will be used.)

##### Parameters

| key | the party's private information. For example, in the case of the Diffie-Hellman key agreement, this would be the party's own Diffie-Hellman private key. |
|---|---|

##### Throws

| [InvalidKeyException](https://developers.google.com/j2objc/javadoc/jre/reference/java/security/InvalidKeyException.html) | if the given key is inappropriate for this key agreement, e.g., is of the wrong type or has an incompatible algorithm type. |
|---|---|