public
class
GCMParameterSpec
extends Object
implements
AlgorithmParameterSpec
java.lang.Object | |
↳ | javax.crypto.spec.GCMParameterSpec |
Specifies the set of parameters required by a Cipher
using the Galois/Counter Mode (GCM) mode.
Simple block cipher modes (such as CBC) generally require only an
initialization vector (such as IvParameterSpec
),
but GCM needs these parameters:
IV
: Initialization Vector (IV) tLen
: length (in bits) of authentication tag T
In addition to the parameters described here, other GCM inputs/output
(Additional Authenticated Data (AAD), Keys, block ciphers,
plain/ciphertext and authentication tags) are handled in the Cipher
class.
Please see RFC 5116 for more information on the Authenticated Encryption with Associated Data (AEAD) algorithm, and NIST Special Publication 800-38D, "NIST Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC."
The GCM specification states that tLen
may only have the
values {128, 120, 112, 104, 96}, or {64, 32} for certain
applications. Other values can be specified for this class, but not
all CSP implementations will support them.
See also:
Public constructors | |
---|---|
GCMParameterSpec(int tLen, byte[] src)
Constructs a GCMParameterSpec using the specified authentication tag bit-length and IV buffer. |
|
GCMParameterSpec(int tLen, byte[] src, int offset, int len)
Constructs a GCMParameterSpec object using the specified authentication tag bit-length and a subset of the specified buffer as the IV. |
Public methods | |
---|---|
byte[]
|
getIV()
Returns the Initialization Vector (IV). |
int
|
getTLen()
Returns the authentication tag length. |
Inherited methods | |
---|---|
From
class
java.lang.Object
|
GCMParameterSpec (int tLen, byte[] src)
Constructs a GCMParameterSpec using the specified authentication tag bit-length and IV buffer.
Parameters | |
---|---|
tLen |
int :
the authentication tag length (in bits) |
src |
byte :
the IV source buffer. The contents of the buffer are
copied to protect against subsequent modification. |
Throws | |
---|---|
IllegalArgumentException |
if tLen is negative,
or src is null.
|
GCMParameterSpec (int tLen, byte[] src, int offset, int len)
Constructs a GCMParameterSpec object using the specified authentication tag bit-length and a subset of the specified buffer as the IV.
Parameters | |
---|---|
tLen |
int :
the authentication tag length (in bits) |
src |
byte :
the IV source buffer. The contents of the
buffer are copied to protect against subsequent modification. |
offset |
int :
the offset in src where the IV starts |
len |
int :
the number of IV bytes |
Throws | |
---|---|
IllegalArgumentException |
if tLen is negative,
src is null, len or offset is negative,
or the sum of offset and len is greater than the
length of the src byte array.
|
byte[] getIV ()
Returns the Initialization Vector (IV).
Returns | |
---|---|
byte[] |
the IV. Creates a new array each time this method is called. |
int getTLen ()
Returns the authentication tag length.
Returns | |
---|---|
int |
the authentication tag length (in bits) |