GCMParameterSpec (Java SE 15 & JDK 15) (original) (raw)

All Implemented Interfaces:

[AlgorithmParameterSpec](../../../java/security/spec/AlgorithmParameterSpec.html "interface in java.security.spec")

public class GCMParameterSpec extends Object implements AlgorithmParameterSpec

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.

Since:

1.7

See Also:

Cipher

• Constructor Summary

Constructors

• Method Summary

Methods declared in class java.lang.Object

[clone](../../../java/lang/Object.html#clone%28%29), [equals](../../../java/lang/Object.html#equals%28java.lang.Object%29), [finalize](../../../java/lang/Object.html#finalize%28%29), [getClass](../../../java/lang/Object.html#getClass%28%29), [hashCode](../../../java/lang/Object.html#hashCode%28%29), [notify](../../../java/lang/Object.html#notify%28%29), [notifyAll](../../../java/lang/Object.html#notifyAll%28%29), [toString](../../../java/lang/Object.html#toString%28%29), [wait](../../../java/lang/Object.html#wait%28%29), [wait](../../../java/lang/Object.html#wait%28long%29), [wait](../../../java/lang/Object.html#wait%28long,int%29)

• Constructor Details

  • GCMParameterSpec

  public GCMParameterSpec​(int tLen, byte[] src)
  Constructs a GCMParameterSpec using the specified authentication tag bit-length and IV buffer.
  Parameters:
  tLen - the authentication tag length (in bits)
  src - the IV source buffer. The contents of the buffer are copied to protect against subsequent modification.
  Throws:
  [IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - if tLen is negative, or src is null.

  • GCMParameterSpec

  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.
  Parameters:
  tLen - the authentication tag length (in bits)
  src - the IV source buffer. The contents of the buffer are copied to protect against subsequent modification.
  offset - the offset in src where the IV starts
  len - the number of IV bytes
  Throws:
  [IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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.

• Method Details

  • getTLen

  public int getTLen()
  Returns the authentication tag length.
  Returns:
  the authentication tag length (in bits)

  • getIV

  public byte[] getIV()
  Returns the Initialization Vector (IV).
  Returns:
  the IV. Creates a new array each time this method is called.