Cipher  |  API reference  |  Android Developers (original) (raw)

public class Cipher
extends [Object](/reference/java/lang/Object) ``

Known direct subclasses

This class provides the functionality of a cryptographic cipher for encryption and decryption. It forms the core of the Java Cryptographic Extension (JCE) framework.

In order to create a Cipher object, the application calls the Cipher's getInstance method, and passes the name of the requested transformation to it. Optionally, the name of a provider may be specified.

A transformation is a string that describes the operation (or set of operations) to be performed on the given input, to produce some output. A transformation always includes the name of a cryptographic algorithm (e.g., DES), and may be followed by a feedback mode and padding scheme.

A transformation is of the form:

• "algorithm/mode/padding" or
• "algorithm"

(in the latter case, provider-specific default values for the mode and padding scheme are used). For example, the following is a valid transformation:

Cipher c = Cipher.getInstance("DES/CBC/PKCS5Padding");
 

Using modes such as CFB and OFB, block ciphers can encrypt data in units smaller than the cipher's actual block size. When requesting such a mode, you may optionally specify the number of bits to be processed at a time by appending this number to the mode name as shown in the "DES/CFB8/NoPadding" and "DES/OFB32/PKCS5Padding" transformations. If no such number is specified, a provider-specific default is used. (For example, the SunJCE provider uses a default of 64 bits for DES.) Thus, block ciphers can be turned into byte-oriented stream ciphers by using an 8 bit mode such as CFB8 or OFB8.

Modes such as Authenticated Encryption with Associated Data (AEAD) provide authenticity assurances for both confidential data and Additional Associated Data (AAD) that is not encrypted. (Please see RFC 5116 for more information on AEAD and AEAD algorithms such as GCM/CCM.) Both confidential and AAD data can be used when calculating the authentication tag (similar to a [Mac](/reference/javax/crypto/Mac)). This tag is appended to the ciphertext during encryption, and is verified on decryption.

AEAD modes such as GCM/CCM perform all AAD authenticity calculations before starting the ciphertext authenticity calculations. To avoid implementations having to internally buffer ciphertext, all AAD data must be supplied to GCM/CCM implementations (via the updateAAD methods) before the ciphertext is processed (via the update and doFinal methods).

Note that GCM mode has a uniqueness requirement on IVs used in encryption with a given key. When IVs are repeated for GCM encryption, such usages are subject to forgery attacks. Thus, after each encryption operation using GCM mode, callers should re-initialize the cipher objects with GCM parameters which has a different IV value.

 GCMParameterSpec s = ...;
 cipher.init(..., s);

 // If the GCM parameters were generated by the provider, it can
 // be retrieved by:
 // cipher.getParameters().getParameterSpec(GCMParameterSpec.class);

 cipher.updateAAD(...);  // AAD
 cipher.update(...);     // Multi-part update
 cipher.doFinal(...);    // conclusion of operation

 // Use a different IV value for every encryption
 byte[] newIv = ...;
 s = new GCMParameterSpec(s.getTLen(), newIv);
 cipher.init(..., s);
 ...

Android provides the following Cipher transformations:

These transformations are described in the Cipher section of the Java Cryptography Architecture Standard Algorithm Name Documentation.

Summary

Constants

DECRYPT_MODE

public static final int DECRYPT_MODE

Constant used to initialize cipher to decryption mode.

Constant Value: 2 (0x00000002)

ENCRYPT_MODE

public static final int ENCRYPT_MODE

Constant used to initialize cipher to encryption mode.

Constant Value: 1 (0x00000001)

PRIVATE_KEY

public static final int PRIVATE_KEY

Constant used to indicate the to-be-unwrapped key is a "private key".

Constant Value: 2 (0x00000002)

PUBLIC_KEY

public static final int PUBLIC_KEY

Constant used to indicate the to-be-unwrapped key is a "public key".

Constant Value: 1 (0x00000001)

SECRET_KEY

public static final int SECRET_KEY

Constant used to indicate the to-be-unwrapped key is a "secret key".

Constant Value: 3 (0x00000003)

UNWRAP_MODE

public static final int UNWRAP_MODE

Constant used to initialize cipher to key-unwrapping mode.

Constant Value: 4 (0x00000004)

WRAP_MODE

public static final int WRAP_MODE

Constant used to initialize cipher to key-wrapping mode.

Constant Value: 3 (0x00000003)

Protected constructors

Cipher

protected Cipher (CipherSpi cipherSpi, Provider provider, String transformation)

Creates a Cipher object.

Public methods

doFinal

public final int doFinal (byte[] input, int inputOffset, int inputLen, byte[] output)

Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. The data is encrypted or decrypted, depending on how this cipher was initialized.

The first inputLen bytes in the input buffer, starting at inputOffset inclusive, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in the output buffer.

If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use[getOutputSize](/reference/javax/crypto/Cipher#getOutputSize%28int%29) to determine how big the output buffer should be.

Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call toinit) more data.

Note: if any exception is thrown, this cipher object may need to be reset before it can be used again.

Note: this method should be copy-safe, which means theinput and output buffers can reference the same byte array and no unprocessed input data is overwritten when the result is copied into the output buffer.

doFinal

public final int doFinal (byte[] output, int outputOffset)

Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialized.

Input data that may have been buffered during a previousupdate operation is processed, with padding (if requested) being applied. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in the output buffer, starting atoutputOffset inclusive.

If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use[getOutputSize](/reference/javax/crypto/Cipher#getOutputSize%28int%29) to determine how big the output buffer should be.

Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call toinit) more data.

Note: if any exception is thrown, this cipher object may need to be reset before it can be used again.

doFinal

public final byte[] doFinal ()

Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialized.

Input data that may have been buffered during a previousupdate operation is processed, with padding (if requested) being applied. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in a new buffer.

Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call toinit) more data.

Note: if any exception is thrown, this cipher object may need to be reset before it can be used again.

doFinal

public final byte[] doFinal (byte[] input)

Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. The data is encrypted or decrypted, depending on how this cipher was initialized.

The bytes in the input buffer, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in a new buffer.

Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call toinit) more data.

Note: if any exception is thrown, this cipher object may need to be reset before it can be used again.

doFinal

public final int doFinal (byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset)

Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. The data is encrypted or decrypted, depending on how this cipher was initialized.

The first inputLen bytes in the input buffer, starting at inputOffset inclusive, and any input bytes that may have been buffered during a previousupdate operation, are processed, with padding (if requested) being applied. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in the output buffer, starting atoutputOffset inclusive.

If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use[getOutputSize](/reference/javax/crypto/Cipher#getOutputSize%28int%29) to determine how big the output buffer should be.

Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call toinit) more data.

Note: if any exception is thrown, this cipher object may need to be reset before it can be used again.

Note: this method should be copy-safe, which means theinput and output buffers can reference the same byte array and no unprocessed input data is overwritten when the result is copied into the output buffer.

doFinal

public final int doFinal (ByteBuffer input, ByteBuffer output)

Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. The data is encrypted or decrypted, depending on how this cipher was initialized.

All input.remaining() bytes starting atinput.position() are processed. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in the output buffer. Upon return, the input buffer's position will be equal to its limit; its limit will not have changed. The output buffer's position will have advanced by n, where n is the value returned by this method; the output buffer's limit will not have changed.

If output.remaining() bytes are insufficient to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use[getOutputSize](/reference/javax/crypto/Cipher#getOutputSize%28int%29) to determine how big the output buffer should be.

Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call toinit) more data.

Note: if any exception is thrown, this cipher object may need to be reset before it can be used again.

Note: this method should be copy-safe, which means theinput and output buffers can reference the same byte array and no unprocessed input data is overwritten when the result is copied into the output buffer.

doFinal

public final byte[] doFinal (byte[] input, int inputOffset, int inputLen)

Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. The data is encrypted or decrypted, depending on how this cipher was initialized.

The first inputLen bytes in the input buffer, starting at inputOffset inclusive, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in a new buffer.

Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call toinit) more data.

Note: if any exception is thrown, this cipher object may need to be reset before it can be used again.

getAlgorithm

public final String getAlgorithm ()

Returns the algorithm name of this Cipher object.

This is the same name that was specified in one of thegetInstance calls that created this Cipher object..

getBlockSize

public final int getBlockSize ()

Returns the block size (in bytes).

getExemptionMechanism

public final ExemptionMechanism getExemptionMechanism ()

Returns the exemption mechanism object used with this cipher.

getIV

public final byte[] getIV ()

Returns the initialization vector (IV) in a new buffer.

This is useful in the case where a random IV was created, or in the context of password-based encryption or decryption, where the IV is derived from a user-supplied password.

getInstance

public static final Cipher getInstance (String transformation)

Returns a Cipher object that implements the specified transformation.

This method traverses the list of registered security Providers, starting with the most preferred Provider. A new Cipher object encapsulating the CipherSpi 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()](/reference/java/security/Security#getProviders%28%29) method.

getInstance

public static final Cipher getInstance (String transformation, String provider)

Returns a Cipher object that implements the specified transformation.

A new Cipher object encapsulating the CipherSpi 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()](/reference/java/security/Security#getProviders%28%29) method.

getInstance

public static final Cipher getInstance (String transformation, Provider provider)

Returns a Cipher object that implements the specified transformation.

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

getMaxAllowedKeyLength

public static final int getMaxAllowedKeyLength (String transformation)

Returns the maximum key length for the specified transformation according to the installed JCE jurisdiction policy files. If JCE unlimited strength jurisdiction policy files are installed, Integer.MAX_VALUE will be returned. For more information on default key size in JCE jurisdiction policy files, please see Appendix E in the Java Cryptography Architecture Reference Guide.

getMaxAllowedParameterSpec

public static final AlgorithmParameterSpec getMaxAllowedParameterSpec (String transformation)

Returns an AlgorithmParameterSpec object which contains the maximum cipher parameter value according to the jurisdiction policy file. If JCE unlimited strength jurisdiction policy files are installed or there is no maximum limit on the parameters for the specified transformation in the policy file, null will be returned.

getOutputSize

public final int getOutputSize (int inputLen)

Returns the length in bytes that an output buffer would need to be in order to hold the result of the next update ordoFinal operation, given the input lengthinputLen (in bytes).

This call takes into account any unprocessed (buffered) data from a previous update call, padding, and AEAD tagging.

The actual output length of the next update ordoFinal call may be smaller than the length returned by this method.

getParameters

public final AlgorithmParameters getParameters ()

Returns the parameters used with this cipher.

The returned parameters may be the same that were used to initialize this cipher, or may contain a combination of default and random parameter values used by the underlying cipher implementation if this cipher requires algorithm parameters but was not initialized with any.

getProvider

public final Provider getProvider ()

Returns the provider of this Cipher object.

init

public final void init (int opmode, Key key, AlgorithmParameters params)

Initializes this cipher with a key and a set of algorithm parameters.

The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode.

If this cipher requires any algorithm parameters andparams is null, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise anInvalidAlgorithmParameterException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using[getParameters](/reference/javax/crypto/Cipher#getParameters%28%29) or[getIV](/reference/javax/crypto/Cipher#getIV%28%29) (if the parameter is an IV).

If this cipher requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.

If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them using the [SecureRandom](/reference/java/security/SecureRandom) 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.)

Note that when a Cipher object is initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

init

public final void init (int opmode, Certificate certificate, SecureRandom random)

Initializes this cipher with the public key from the given certificate and a source of randomness.

The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode.

If the certificate is of type X.509 and has a key usage extension field marked as critical, and the value of the key usage extension field implies that the public key in the certificate and its corresponding private key are not supposed to be used for the operation represented by the value ofopmode, an InvalidKeyException is thrown.

If this cipher requires any algorithm parameters that cannot be derived from the public key in the given certificate, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise anInvalidKeyException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using[getParameters](/reference/javax/crypto/Cipher#getParameters%28%29) or[getIV](/reference/javax/crypto/Cipher#getIV%28%29) (if the parameter is an IV).

If this cipher requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.

If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random.

Note that when a Cipher object is initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

init

public final void init (int opmode, Key key, SecureRandom random)

Initializes this cipher with a key and a source of randomness.

The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode.

If this cipher requires any algorithm parameters that cannot be derived from the given key, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise anInvalidKeyException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using[getParameters](/reference/javax/crypto/Cipher#getParameters%28%29) or[getIV](/reference/javax/crypto/Cipher#getIV%28%29) (if the parameter is an IV).

If this cipher requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.

If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random.

Note that when a Cipher object is initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

init

public final void init (int opmode, Key key, AlgorithmParameterSpec params)

Initializes this cipher with a key and a set of algorithm parameters.

The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode.

If this cipher requires any algorithm parameters andparams is null, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise anInvalidAlgorithmParameterException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using[getParameters](/reference/javax/crypto/Cipher#getParameters%28%29) or[getIV](/reference/javax/crypto/Cipher#getIV%28%29) (if the parameter is an IV).

If this cipher requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.

If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them using the [SecureRandom](/reference/java/security/SecureRandom) 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.)

Note that when a Cipher object is initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

init

public final void init (int opmode, Key key)

Initializes this cipher with a key.

The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode.

If this cipher requires any algorithm parameters that cannot be derived from the given key, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise anInvalidKeyException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using[getParameters](/reference/javax/crypto/Cipher#getParameters%28%29) or[getIV](/reference/javax/crypto/Cipher#getIV%28%29) (if the parameter is an IV).

If this cipher requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.

If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them using the [SecureRandom](/reference/java/security/SecureRandom) 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.)

Note that when a Cipher object is initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

init

public final void init (int opmode, Key key, AlgorithmParameterSpec params, SecureRandom random)

Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness.

The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode.

If this cipher requires any algorithm parameters andparams is null, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise anInvalidAlgorithmParameterException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using[getParameters](/reference/javax/crypto/Cipher#getParameters%28%29) or[getIV](/reference/javax/crypto/Cipher#getIV%28%29) (if the parameter is an IV).

If this cipher requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.

If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random.

Note that when a Cipher object is initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

init

public final void init (int opmode, Certificate certificate)

Initializes this cipher with the public key from the given certificate.

The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode.

If the certificate is of type X.509 and has a key usage extension field marked as critical, and the value of the key usage extension field implies that the public key in the certificate and its corresponding private key are not supposed to be used for the operation represented by the value of opmode, an InvalidKeyException is thrown.

If this cipher requires any algorithm parameters that cannot be derived from the public key in the given certificate, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise an InvalidKeyException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using[getParameters](/reference/javax/crypto/Cipher#getParameters%28%29) or[getIV](/reference/javax/crypto/Cipher#getIV%28%29) (if the parameter is an IV).

If this cipher requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.

If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them using theSecureRandom 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.)

Note that when a Cipher object is initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

init

public final void init (int opmode, Key key, AlgorithmParameters params, SecureRandom random)

Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness.

The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode.

If this cipher requires any algorithm parameters andparams is null, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise anInvalidAlgorithmParameterException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using[getParameters](/reference/javax/crypto/Cipher#getParameters%28%29) or[getIV](/reference/javax/crypto/Cipher#getIV%28%29) (if the parameter is an IV).

If this cipher requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.

If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random.

Note that when a Cipher object is initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

unwrap

public final Key unwrap (byte[] wrappedKey, String wrappedKeyAlgorithm, int wrappedKeyType)

Unwrap a previously wrapped key.

update

public final byte[] update (byte[] input)

Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.

The bytes in the input buffer are processed, and the result is stored in a new buffer.

If input has a length of zero, this method returnsnull.

update

public final int update (byte[] input, int inputOffset, int inputLen, byte[] output)

Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.

The first inputLen bytes in the input buffer, starting at inputOffset inclusive, are processed, and the result is stored in the output buffer.

If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use[getOutputSize](/reference/javax/crypto/Cipher#getOutputSize%28int%29) to determine how big the output buffer should be.

If inputLen is zero, this method returns a length of zero.

Note: this method should be copy-safe, which means theinput and output buffers can reference the same byte array and no unprocessed input data is overwritten when the result is copied into the output buffer.

update

public final byte[] update (byte[] input, int inputOffset, int inputLen)

Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.

The first inputLen bytes in the input buffer, starting at inputOffset inclusive, are processed, and the result is stored in a new buffer.

If inputLen is zero, this method returnsnull.

update

public final int update (ByteBuffer input, ByteBuffer output)

Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.

All input.remaining() bytes starting atinput.position() are processed. The result is stored in the output buffer. Upon return, the input buffer's position will be equal to its limit; its limit will not have changed. The output buffer's position will have advanced by n, where n is the value returned by this method; the output buffer's limit will not have changed.

If output.remaining() bytes are insufficient to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use[getOutputSize](/reference/javax/crypto/Cipher#getOutputSize%28int%29) to determine how big the output buffer should be.

Note: this method should be copy-safe, which means theinput and output buffers can reference the same block of memory and no unprocessed input data is overwritten when the result is copied into the output buffer.

update

public final int update (byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset)

Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.

The first inputLen bytes in the input buffer, starting at inputOffset inclusive, are processed, and the result is stored in the output buffer, starting atoutputOffset inclusive.

If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use[getOutputSize](/reference/javax/crypto/Cipher#getOutputSize%28int%29) to determine how big the output buffer should be.

If inputLen is zero, this method returns a length of zero.

Note: this method should be copy-safe, which means theinput and output buffers can reference the same byte array and no unprocessed input data is overwritten when the result is copied into the output buffer.

updateAAD

public final void updateAAD (byte[] src, int offset, int len)

Continues a multi-part update of the Additional Authentication Data (AAD), using a subset of the provided buffer.

Calls to this method provide AAD to the cipher when operating in modes such as AEAD (GCM/CCM). If this cipher is operating in either GCM or CCM mode, all AAD must be supplied before beginning operations on the ciphertext (via the update and doFinal methods).

updateAAD

public final void updateAAD (ByteBuffer src)

Continues a multi-part update of the Additional Authentication Data (AAD).

Calls to this method provide AAD to the cipher when operating in modes such as AEAD (GCM/CCM). If this cipher is operating in either GCM or CCM mode, all AAD must be supplied before beginning operations on the ciphertext (via the update and doFinal methods).

All src.remaining() bytes starting atsrc.position() are processed. Upon return, the input buffer's position will be equal to its limit; its limit will not have changed.

updateAAD

public final void updateAAD (byte[] src)

Continues a multi-part update of the Additional Authentication Data (AAD).

Calls to this method provide AAD to the cipher when operating in modes such as AEAD (GCM/CCM). If this cipher is operating in either GCM or CCM mode, all AAD must be supplied before beginning operations on the ciphertext (via the update and doFinal methods).

wrap

public final byte[] wrap (Key key)

Wrap a key.