javax.crypto.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.
javax.crypto.Cipher
| Access | Constructor and Description |
|---|---|
| public | GCMParameterSpec(int
the authentication tag length (in bits) tLen, byte[] the IV source buffer. The contents of the buffer are
copied to protect against subsequent modification. src)Constructs a GCMParameterSpec using the specified authentication tag bit-length and IV buffer. |
| public | GCMParameterSpec(int
the authentication tag length (in bits) tLen, byte[] the IV source buffer. The contents of the
buffer are copied to protect against subsequent modification. src, int the offset in offset, int src where the IV startsthe number of IV bytes len)Constructs a GCMParameterSpec object using the specified authentication tag bit-length and a subset of the specified buffer as the IV. |
| Modifier and Type | Method and Description |
|---|---|
| public byte[] | Returns: the IV. Creates a new array each time this method is called.Returns the Initialization Vector (IV). |
| public int | |
| private void |
| GCMParameterSpec | back to summary |
|---|---|
| public GCMParameterSpec(int tLen, byte[] src) Constructs a GCMParameterSpec using the specified authentication tag bit-length and IV buffer.
| |
| GCMParameterSpec | back to summary |
|---|---|
| public 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.
| |
| getIV | back to summary |
|---|---|
| public byte[] getIV() Returns the Initialization Vector (IV).
| |
| getTLen | back to summary |
|---|---|
| public int getTLen() Returns the authentication tag length.
| |
| init | back to summary |
|---|---|
| private void init(int tLen, byte[] src, int offset, int len) | |