javax.crypto

Class Cipher

java.lang.Object

javax.crypto.Cipher

public class Cipher
extends Object

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). 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);
     ...

 

Every implementation of the Java platform is required to support the following standard Cipher transformations with the keysizes in parentheses:

• AES/CBC/NoPadding (128)
• AES/CBC/PKCS5Padding (128)
• AES/ECB/NoPadding (128)
• AES/ECB/PKCS5Padding (128)
• DES/CBC/NoPadding (56)
• DES/CBC/PKCS5Padding (56)
• DES/ECB/NoPadding (56)
• DES/ECB/PKCS5Padding (56)
• DESede/CBC/NoPadding (168)
• DESede/CBC/PKCS5Padding (168)
• DESede/ECB/NoPadding (168)
• DESede/ECB/PKCS5Padding (168)
• RSA/ECB/PKCS1Padding (1024, 2048)
• RSA/ECB/OAEPWithSHA-1AndMGF1Padding (1024, 2048)
• RSA/ECB/OAEPWithSHA-256AndMGF1Padding (1024, 2048)

These transformations are described in the Cipher section of the Java Cryptography Architecture Standard Algorithm Name Documentation. Consult the release documentation for your implementation to see if any other transformations are supported.

Since:

1.4

Author:

Jan Luehe

See Also:

SecretKey

Field Summary

Fields

Modifier and Type	Field and Description
static int	DECRYPT_MODE Constant used to initialize cipher to decryption mode.
static int	ENCRYPT_MODE Constant used to initialize cipher to encryption mode.
static int	PRIVATE_KEY Constant used to indicate the to-be-unwrapped key is a "private key".
static int	PUBLIC_KEY Constant used to indicate the to-be-unwrapped key is a "public key".
static int	SECRET_KEY Constant used to indicate the to-be-unwrapped key is a "secret key".
static int	UNWRAP_MODE Constant used to initialize cipher to key-unwrapping mode.
static int	WRAP_MODE Constant used to initialize cipher to key-wrapping mode.

Method Summary

Modifier and Type	Method and Description
byte[]	doFinal() Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialized.
byte[]	doFinal(byte[] input) Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
int	doFinal(byte[] output, int outputOffset) Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialized.
byte[]	doFinal(byte[] input, int inputOffset, int inputLen) Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
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.
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.
String	getAlgorithm() Returns the algorithm name of this Cipher object.
int	getBlockSize() Returns the block size (in bytes).
static Cipher	getInstance(String transformation) Returns a Cipher object that implements the specified transformation.
static Cipher	getInstance(String transformation, String provider) Returns a Cipher object that implements the specified transformation.
byte[]	getIV() Returns the initialization vector (IV) in a new buffer.
static int	getMaxAllowedKeyLength(String transformation) Returns the maximum key length for the specified transformation according to the installed JCE jurisdiction policy files.
static AlgorithmParameterSpec	getMaxAllowedParameterSpec(String transformation) Returns an AlgorithmParameterSpec object which contains the maximum cipher parameter value according to the jurisdiction policy file.
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 or doFinal operation, given the input length inputLen (in bytes).
void	init(int opmode, Certificate certificate) Initializes this cipher with the public key from the given certificate.
void	init(int opmode, Certificate certificate, SecureRandom random) Initializes this cipher with the public key from the given certificate and a source of randomness.
void	init(int opmode, Key key) Initializes this cipher with a key.
void	init(int opmode, Key key, AlgorithmParameterSpec params) Initializes this cipher with a key and a set of algorithm parameters.
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.
void	init(int opmode, Key key, SecureRandom random) Initializes this cipher with a key and a source of randomness.
Key	unwrap(byte[] wrappedKey, String wrappedKeyAlgorithm, int wrappedKeyType) Unwrap a previously wrapped key.
byte[]	update(byte[] input) Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.
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.
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.
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.
void	updateAAD(byte[] src) Continues a multi-part update of the Additional Authentication Data (AAD).
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.
byte[]	wrap(Key key) Wrap a key.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DECRYPT_MODE

public static final int DECRYPT_MODE

Constant used to initialize cipher to decryption mode.

See Also:

Constant Field Values

ENCRYPT_MODE

public static final int ENCRYPT_MODE

Constant used to initialize cipher to encryption mode.

See Also:

Constant Field Values

PRIVATE_KEY

public static final int PRIVATE_KEY

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

See Also:

Constant Field Values

PUBLIC_KEY

public static final int PUBLIC_KEY

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

See Also:

Constant Field Values

SECRET_KEY

public static final int SECRET_KEY

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

See Also:

Constant Field Values

UNWRAP_MODE

public static final int UNWRAP_MODE

Constant used to initialize cipher to key-unwrapping mode.

See Also:

Constant Field Values

WRAP_MODE

public static final int WRAP_MODE

Constant used to initialize cipher to key-wrapping mode.

See Also:

Constant Field Values

Method Detail

doFinal

public final byte[] doFinal()
                     throws IllegalBlockSizeException,
                            BadPaddingException

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

Input data that may have been buffered during a previous update 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 to init) more data.

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

Returns:

the new buffer with the result

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized)

IllegalBlockSizeException - if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided.

BadPaddingException - if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes

AEADBadTagException - if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value

doFinal

public final byte[] doFinal(byte[] input)
                     throws IllegalBlockSizeException,
                            BadPaddingException

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 to init) more data.

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

Parameters:

input - the input buffer

Returns:

the new buffer with the result

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized)

IllegalBlockSizeException - if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided.

BadPaddingException - if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes

AEADBadTagException - if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value

doFinal

public final int doFinal(byte[] output,
                         int outputOffset)
                  throws IllegalBlockSizeException,
                         ShortBufferException,
                         BadPaddingException

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

Input data that may have been buffered during a previous update 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 at outputOffset 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 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 to init) more data.

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

Parameters:

output - the buffer for the result

outputOffset - the offset in output where the result is stored

Returns:

the number of bytes stored in output

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized)

IllegalBlockSizeException - if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided.

ShortBufferException - if the given output buffer is too small to hold the result

BadPaddingException - if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes

AEADBadTagException - if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value

doFinal

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

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 to init) more data.

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

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

Returns:

the new buffer with the result

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized)

IllegalBlockSizeException - if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided.

BadPaddingException - if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes

AEADBadTagException - if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value

doFinal

public final int doFinal(byte[] input,
                         int inputOffset,
                         int inputLen,
                         byte[] output)
                  throws ShortBufferException,
                         IllegalBlockSizeException,
                         BadPaddingException

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 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 to init) 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 the input 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.

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

output - the buffer for the result

Returns:

the number of bytes stored in output

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized)

IllegalBlockSizeException - if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided.

ShortBufferException - if the given output buffer is too small to hold the result

BadPaddingException - if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes

AEADBadTagException - if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value

doFinal

public final int doFinal(byte[] input,
                         int inputOffset,
                         int inputLen,
                         byte[] output,
                         int outputOffset)
                  throws ShortBufferException,
                         IllegalBlockSizeException,
                         BadPaddingException

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, starting at outputOffset 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 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 to init) 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 the input 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.

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

output - the buffer for the result

outputOffset - the offset in output where the result is stored

Returns:

the number of bytes stored in output

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized)

IllegalBlockSizeException - if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided.

ShortBufferException - if the given output buffer is too small to hold the result

BadPaddingException - if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes

AEADBadTagException - if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value

getAlgorithm

public final String getAlgorithm()

Returns the algorithm name of this Cipher object.

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

Returns:

the algorithm name of this Cipher object.

getBlockSize

public final int getBlockSize()

Returns the block size (in bytes).

Returns:

the block size (in bytes), or 0 if the underlying algorithm is not a block cipher

getInstance

public static final Cipher getInstance(String transformation)
                                throws NoSuchAlgorithmException,
                                       NoSuchPaddingException

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.

Parameters:

transformation - the name of the transformation, e.g., DES/CBC/PKCS5Padding. See the Cipher section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard transformation names.

Returns:

a cipher that implements the requested transformation.

Throws:

NoSuchAlgorithmException - if transformation is null, empty, in an invalid format, or if no Provider supports a CipherSpi implementation for the specified algorithm.

NoSuchPaddingException - if transformation contains a padding scheme that is not available.

getInstance

public static final Cipher getInstance(String transformation,
                                       String provider)
                                throws NoSuchAlgorithmException,
                                       NoSuchProviderException,
                                       NoSuchPaddingException

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.

Parameters:

transformation - the name of the transformation, e.g., DES/CBC/PKCS5Padding. See the Cipher section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard transformation names.

provider - the name of the provider.

Returns:

a cipher that implements the requested transformation.

Throws:

NoSuchAlgorithmException - if transformation is null, empty, in an invalid format, or if a CipherSpi implementation for the specified algorithm is not available from the specified provider.

NoSuchProviderException - if the specified provider is not registered in the security provider list.

NoSuchPaddingException - if transformation contains a padding scheme that is not available.

IllegalArgumentException - if the provider is null or empty.

getIV

@Nullable
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.

Returns:

the initialization vector in a new buffer, or null if the underlying algorithm does not use an IV, or if the IV has not yet been set.

getMaxAllowedKeyLength

public static final int getMaxAllowedKeyLength(String transformation)
                                        throws NoSuchAlgorithmException

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.

Parameters:

transformation - the cipher transformation.

Returns:

the maximum key length in bits or Integer.MAX_VALUE.

Throws:

NullPointerException - if transformation is null.

NoSuchAlgorithmException - if transformation is not a valid transformation, i.e. in the form of "algorithm" or "algorithm/mode/padding".

Since:

1.5

getMaxAllowedParameterSpec

@Nullable
public static final AlgorithmParameterSpec getMaxAllowedParameterSpec(String transformation)
                                                                         throws NoSuchAlgorithmException

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.

Parameters:

transformation - the cipher transformation.

Returns:

an AlgorithmParameterSpec which holds the maximum value or null.

Throws:

NullPointerException - if transformation is null.

NoSuchAlgorithmException - if transformation is not a valid transformation, i.e. in the form of "algorithm" or "algorithm/mode/padding".

Since:

1.5

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 or doFinal operation, given the input length inputLen (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 or doFinal call may be smaller than the length returned by this method.

Parameters:

inputLen - the input length (in bytes)

Returns:

the required output buffer size (in bytes)

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not yet been initialized)

init

public final void init(int opmode,
                       Certificate certificate)
                throws InvalidKeyException

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 getIV (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 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.

Parameters:

opmode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)

certificate - the certificate

Throws:

InvalidKeyException - if the public key in the given certificate is inappropriate for initializing this cipher, or this cipher requires algorithm parameters that cannot be determined from the public key in the given certificate, or the keysize of the public key in the given certificate has a keysize that exceeds the maximum allowable keysize (as determined by the configured jurisdiction policy files).

UnsupportedOperationException - if (@code opmode} is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi.

init

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

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 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 getIV (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.

Parameters:

opmode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)

certificate - the certificate

random - the source of randomness

Throws:

InvalidKeyException - if the public key in the given certificate is inappropriate for initializing this cipher, or this cipher requires algorithm parameters that cannot be determined from the public key in the given certificate, or the keysize of the public key in the given certificate has a keysize that exceeds the maximum allowable keysize (as determined by the configured jurisdiction policy files).

UnsupportedOperationException - if (@code opmode} is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi.

init

public final void init(int opmode,
                       Key key)
                throws InvalidKeyException

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 an InvalidKeyException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using getIV (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 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.

Parameters:

opmode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)

key - the key

Throws:

InvalidKeyException - if the given key is inappropriate for initializing this cipher, or requires algorithm parameters that cannot be determined from the given key, or if the given key has a keysize that exceeds the maximum allowable keysize (as determined from the configured jurisdiction policy files).

UnsupportedOperationException - if (@code opmode} is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi.

init

public final void init(int opmode,
                       Key key,
                       @Nullable
                       AlgorithmParameterSpec params)
                throws InvalidKeyException,
                       InvalidAlgorithmParameterException

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 and params 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 an InvalidAlgorithmParameterException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using getIV (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 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.

Parameters:

opmode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)

key - the encryption key

params - the algorithm parameters

Throws:

InvalidKeyException - if the given key is inappropriate for initializing this cipher, or its keysize exceeds the maximum allowable keysize (as determined from the configured jurisdiction policy files).

InvalidAlgorithmParameterException - if the given algorithm parameters are inappropriate for this cipher, or this cipher requires algorithm parameters and params is null, or the given algorithm parameters imply a cryptographic strength that would exceed the legal limits (as determined from the configured jurisdiction policy files).

UnsupportedOperationException - if (@code opmode} is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi.

init

public final void init(int opmode,
                       Key key,
                       @Nullable
                       AlgorithmParameterSpec params,
                       SecureRandom random)
                throws InvalidKeyException,
                       InvalidAlgorithmParameterException

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 and params 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 an InvalidAlgorithmParameterException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using getIV (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.

Parameters:

opmode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)

key - the encryption key

params - the algorithm parameters

random - the source of randomness

Throws:

InvalidKeyException - if the given key is inappropriate for initializing this cipher, or its keysize exceeds the maximum allowable keysize (as determined from the configured jurisdiction policy files).

InvalidAlgorithmParameterException - if the given algorithm parameters are inappropriate for this cipher, or this cipher requires algorithm parameters and params is null, or the given algorithm parameters imply a cryptographic strength that would exceed the legal limits (as determined from the configured jurisdiction policy files).

UnsupportedOperationException - if (@code opmode} is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi.

init

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

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 an InvalidKeyException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using getIV (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.

Parameters:

opmode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)

key - the encryption key

random - the source of randomness

Throws:

InvalidKeyException - if the given key is inappropriate for initializing this cipher, or requires algorithm parameters that cannot be determined from the given key, or if the given key has a keysize that exceeds the maximum allowable keysize (as determined from the configured jurisdiction policy files).

UnsupportedOperationException - if (@code opmode} is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi.

unwrap

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

Unwrap a previously wrapped key.

Parameters:

wrappedKey - the key to be unwrapped.

wrappedKeyAlgorithm - the algorithm associated with the wrapped key.

wrappedKeyType - the type of the wrapped key. This must be one of SECRET_KEY, PRIVATE_KEY, or PUBLIC_KEY.

Returns:

the unwrapped key.

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized).

NoSuchAlgorithmException - if no installed providers can create keys of type wrappedKeyType for the wrappedKeyAlgorithm.

InvalidKeyException - if wrappedKey does not represent a wrapped key of type wrappedKeyType for the wrappedKeyAlgorithm.

UnsupportedOperationException - if the corresponding method in the CipherSpi is not supported.

update

@Nullable
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 returns null.

Parameters:

input - the input buffer

Returns:

the new buffer with the result, or null if the underlying cipher is a block cipher and the input data is too short to result in a new block.

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized)

update

@Nullable
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 returns null.

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

Returns:

the new buffer with the result, or null if the underlying cipher is a block cipher and the input data is too short to result in a new block.

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized)

update

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

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 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 the input 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.

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

output - the buffer for the result

Returns:

the number of bytes stored in output

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized)

ShortBufferException - if the given output buffer is too small to hold the result

update

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

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 at outputOffset 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 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 the input 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.

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

output - the buffer for the result

outputOffset - the offset in output where the result is stored

Returns:

the number of bytes stored in output

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized)

ShortBufferException - if the given output buffer is too small to hold the result

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).

Parameters:

src - the buffer containing the Additional Authentication Data

Throws:

IllegalArgumentException - if the src byte array is null

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized), does not accept AAD, or if operating in either GCM or CCM mode and one of the update methods has already been called for the active encryption/decryption operation

UnsupportedOperationException - if the corresponding method in the CipherSpi has not been overridden by an implementation

Since:

1.7

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).

Parameters:

src - the buffer containing the AAD

offset - the offset in src where the AAD input starts

len - the number of AAD bytes

Throws:

IllegalArgumentException - if the src byte array is null, or the offset or length is less than 0, or the sum of the offset and len is greater than the length of the src byte array

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized), does not accept AAD, or if operating in either GCM or CCM mode and one of the update methods has already been called for the active encryption/decryption operation

UnsupportedOperationException - if the corresponding method in the CipherSpi has not been overridden by an implementation

Since:

1.7

wrap

public final byte[] wrap(Key key)
                  throws IllegalBlockSizeException,
                         InvalidKeyException

Wrap a key.

Parameters:

key - the key to be wrapped.

Returns:

the wrapped key.

Throws:

IllegalStateException - if this cipher is in a wrong state (e.g., has not been initialized).

IllegalBlockSizeException - if this cipher is a block cipher, no padding has been requested, and the length of the encoding of the key to be wrapped is not a multiple of the block size.

InvalidKeyException - if it is impossible or unsafe to wrap the key with this cipher (e.g., a hardware protected key is being passed to a software-only cipher).

UnsupportedOperationException - if the corresponding method in the CipherSpi is not supported.