KeyAgreement (Java SE 11 & JDK 11 ) (original) (raw)

• • Constructor Detail

     * #### KeyAgreement  
     protected KeyAgreement​([KeyAgreementSpi](KeyAgreementSpi.html "class in javax.crypto") keyAgreeSpi,  
                            [Provider](../../java/security/Provider.html "class in java.security") provider,  
                            [String](../../java/lang/String.html "class in java.lang") algorithm)  
     Creates a KeyAgreement object.  
     Parameters:  
     `keyAgreeSpi` \- the delegate  
     `provider` \- the provider  
     `algorithm` \- the algorithm  

  • Method Detail

    * #### getAlgorithm  
    public final [String](../../java/lang/String.html "class in java.lang") 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.  
    * #### getInstance  
    public static final [KeyAgreement](KeyAgreement.html "class in javax.crypto") getInstance​([String](../../java/lang/String.html "class in java.lang") algorithm)  
                                          throws [NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security")  
    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 [Security.getProviders()](../../java/security/Security.html#getProviders%28%29) method.  
    Implementation Note:  
    The JDK Reference Implementation additionally uses the`jdk.security.provider.preferred` [Security](../../java/security/Security.html#getProperty%28java.lang.String%29) property to determine the preferred provider order for the specified algorithm. This may be different than the order of providers returned by[Security.getProviders()](../../java/security/Security.html#getProviders%28%29).  
    Parameters:  
    `algorithm` \- the standard name of the requested key agreement algorithm. See the KeyAgreement section in the [ Java Security Standard Algorithm Names Specification](../../../../specs/security/standard-names.html#keyagreement-algorithms) for information about standard algorithm names.  
    Returns:  
    the new `KeyAgreement` object  
    Throws:  
    `[NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security")` \- if no `Provider` supports a`KeyAgreementSpi` implementation for the specified algorithm  
    `[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if `algorithm` is `null`  
    See Also:  
    [Provider](../../java/security/Provider.html "class in java.security")  
    * #### getInstance  
    public static final [KeyAgreement](KeyAgreement.html "class in javax.crypto") getInstance​([String](../../java/lang/String.html "class in java.lang") algorithm,  
                                                 [String](../../java/lang/String.html "class in java.lang") provider)  
                                          throws [NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security"),  
                                                 [NoSuchProviderException](../../java/security/NoSuchProviderException.html "class in java.security")  
    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 [Security.getProviders()](../../java/security/Security.html#getProviders%28%29) method.  
    Parameters:  
    `algorithm` \- the standard name of the requested key agreement algorithm. See the KeyAgreement section in the [ Java Security Standard Algorithm Names Specification](../../../../specs/security/standard-names.html#keyagreement-algorithms) for information about standard algorithm names.  
    `provider` \- the name of the provider.  
    Returns:  
    the new `KeyAgreement` object  
    Throws:  
    `[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if the `provider` is `null` or empty  
    `[NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security")` \- if a `KeyAgreementSpi` implementation for the specified algorithm is not available from the specified provider  
    `[NoSuchProviderException](../../java/security/NoSuchProviderException.html "class in java.security")` \- if the specified provider is not registered in the security provider list  
    `[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if `algorithm` is `null`  
    See Also:  
    [Provider](../../java/security/Provider.html "class in java.security")  
    * #### getInstance  
    public static final [KeyAgreement](KeyAgreement.html "class in javax.crypto") getInstance​([String](../../java/lang/String.html "class in java.lang") algorithm,  
                                                 [Provider](../../java/security/Provider.html "class in java.security") provider)  
                                          throws [NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security")  
    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 Security Standard Algorithm Names Specification](../../../../specs/security/standard-names.html#keyagreement-algorithms) for information about standard algorithm names.  
    `provider` \- the provider.  
    Returns:  
    the new `KeyAgreement` object  
    Throws:  
    `[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if the `provider` is `null`  
    `[NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security")` \- if a `KeyAgreementSpi` implementation for the specified algorithm is not available from the specified Provider object  
    `[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if `algorithm` is `null`  
    See Also:  
    [Provider](../../java/security/Provider.html "class in java.security")  
    * #### getProvider  
    public final [Provider](../../java/security/Provider.html "class in java.security") getProvider()  
    Returns the provider of this `KeyAgreement` object.  
    Returns:  
    the provider of this `KeyAgreement` object  
    * #### init  
    public final void init​([Key](../../java/security/Key.html "interface in java.security") key)  
                    throws [InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security")  
    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[SecureRandom](../../java/security/SecureRandom.html "class in java.security") 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](../../java/security/InvalidKeyException.html "class in java.security")` \- if the given key is inappropriate for this key agreement, e.g., is of the wrong type or has an incompatible algorithm type.  
    * #### init  
    public final void init​([Key](../../java/security/Key.html "interface in java.security") key,  
                           [SecureRandom](../../java/security/SecureRandom.html "class in java.security") random)  
                    throws [InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security")  
    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](../../java/security/InvalidKeyException.html "class in java.security")` \- if the given key is inappropriate for this key agreement, e.g., is of the wrong type or has an incompatible algorithm type.  
    * #### init  
    public final void init​([Key](../../java/security/Key.html "interface in java.security") key,  
                           [AlgorithmParameterSpec](../../java/security/spec/AlgorithmParameterSpec.html "interface in java.security.spec") params)  
                    throws [InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security"),  
                           [InvalidAlgorithmParameterException](../../java/security/InvalidAlgorithmParameterException.html "class in java.security")  
    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[SecureRandom](../../java/security/SecureRandom.html "class in java.security") 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](../../java/security/InvalidKeyException.html "class in java.security")` \- if the given key is inappropriate for this key agreement, e.g., is of the wrong type or has an incompatible algorithm type.  
    `[InvalidAlgorithmParameterException](../../java/security/InvalidAlgorithmParameterException.html "class in java.security")` \- if the given parameters are inappropriate for this key agreement.  
    * #### init  
    public final void init​([Key](../../java/security/Key.html "interface in java.security") key,  
                           [AlgorithmParameterSpec](../../java/security/spec/AlgorithmParameterSpec.html "interface in java.security.spec") params,  
                           [SecureRandom](../../java/security/SecureRandom.html "class in java.security") random)  
                    throws [InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security"),  
                           [InvalidAlgorithmParameterException](../../java/security/InvalidAlgorithmParameterException.html "class in java.security")  
    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](../../java/security/InvalidKeyException.html "class in java.security")` \- if the given key is inappropriate for this key agreement, e.g., is of the wrong type or has an incompatible algorithm type.  
    `[InvalidAlgorithmParameterException](../../java/security/InvalidAlgorithmParameterException.html "class in java.security")` \- if the given parameters are inappropriate for this key agreement.  
    * #### doPhase  
    public final [Key](../../java/security/Key.html "interface in java.security") doPhase​([Key](../../java/security/Key.html "interface in java.security") key,  
                             boolean lastPhase)  
                      throws [InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security"),  
                             [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")  
    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](../../java/security/InvalidKeyException.html "class in java.security")` \- if the given key is inappropriate for this phase.  
    `[IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")` \- if this key agreement has not been initialized.  
    * #### generateSecret  
    public final byte[] generateSecret()  
                                throws [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang")  
    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](../../java/lang/IllegalStateException.html "class in java.lang")` \- if this key agreement has not been completed yet  
    * #### generateSecret  
    public final int generateSecret​(byte[] sharedSecret,  
                                    int offset)  
                             throws [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang"),  
                                    [ShortBufferException](ShortBufferException.html "class in javax.crypto")  
    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](../../java/lang/IllegalStateException.html "class in java.lang")` \- if this key agreement has not been completed yet  
    `[ShortBufferException](ShortBufferException.html "class in javax.crypto")` \- if the given output buffer is too small to hold the secret  
    * #### generateSecret  
    public final [SecretKey](SecretKey.html "interface in javax.crypto") generateSecret​([String](../../java/lang/String.html "class in java.lang") algorithm)  
                                   throws [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang"),  
                                          [NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security"),  
                                          [InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security")  
    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](../../java/lang/IllegalStateException.html "class in java.lang")` \- if this key agreement has not been completed yet  
    `[NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security")` \- if the specified secret-key algorithm is not available  
    `[InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security")` \- 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)