Package org.bouncycastle.crypto.macs
Class Poly1305
- java.lang.Object
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- org.bouncycastle.crypto.macs.Poly1305
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- All Implemented Interfaces:
Mac
public class Poly1305 extends java.lang.Object implements Mac
Poly1305 message authentication code, designed by D. J. Bernstein.Poly1305 computes a 128-bit (16 bytes) authenticator, using a 128 bit nonce and a 256 bit key consisting of a 128 bit key applied to an underlying cipher, and a 128 bit key (with 106 effective key bits) used in the authenticator.
The polynomial calculation in this implementation is adapted from the public domain poly1305-donna-unrolled C implementation by Andrew M (@floodyberry).
- See Also:
Poly1305KeyGenerator
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Constructor Summary
Constructors Constructor Description Poly1305()
Constructs a Poly1305 MAC, where the key passed to init() will be used directly.Poly1305(BlockCipher cipher)
Constructs a Poly1305 MAC, using a 128 bit block cipher.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
doFinal(byte[] out, int outOff)
Compute the final stage of the MAC writing the output to the out parameter.java.lang.String
getAlgorithmName()
Return the name of the algorithm the MAC implements.int
getMacSize()
Return the block size for this MAC (in bytes).void
init(CipherParameters params)
Initialises the Poly1305 MAC.void
reset()
Reset the MAC.void
update(byte in)
add a single byte to the mac for processing.void
update(byte[] in, int inOff, int len)
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Constructor Detail
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Poly1305
public Poly1305()
Constructs a Poly1305 MAC, where the key passed to init() will be used directly.
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Poly1305
public Poly1305(BlockCipher cipher)
Constructs a Poly1305 MAC, using a 128 bit block cipher.
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Method Detail
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init
public void init(CipherParameters params) throws java.lang.IllegalArgumentException
Initialises the Poly1305 MAC.- Specified by:
init
in interfaceMac
- Parameters:
params
- if used with a block cipher, then aParametersWithIV
containing a 128 bit nonce and aKeyParameter
with a 256 bit key complying to thePoly1305 key format
, otherwise just theKeyParameter
.- Throws:
java.lang.IllegalArgumentException
- if the params argument is inappropriate.
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getAlgorithmName
public java.lang.String getAlgorithmName()
Description copied from interface:Mac
Return the name of the algorithm the MAC implements.- Specified by:
getAlgorithmName
in interfaceMac
- Returns:
- the name of the algorithm the MAC implements.
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getMacSize
public int getMacSize()
Description copied from interface:Mac
Return the block size for this MAC (in bytes).- Specified by:
getMacSize
in interfaceMac
- Returns:
- the block size for this MAC in bytes.
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update
public void update(byte in) throws java.lang.IllegalStateException
Description copied from interface:Mac
add a single byte to the mac for processing.
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update
public void update(byte[] in, int inOff, int len) throws DataLengthException, java.lang.IllegalStateException
- Specified by:
update
in interfaceMac
- Parameters:
in
- the array containing the input.inOff
- the index in the array the data begins at.len
- the length of the input starting at inOff.- Throws:
DataLengthException
- if there isn't enough data in in.java.lang.IllegalStateException
- if the MAC is not initialised.
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doFinal
public int doFinal(byte[] out, int outOff) throws DataLengthException, java.lang.IllegalStateException
Description copied from interface:Mac
Compute the final stage of the MAC writing the output to the out parameter.doFinal leaves the MAC in the same state it was after the last init.
- Specified by:
doFinal
in interfaceMac
- Parameters:
out
- the array the MAC is to be output to.outOff
- the offset into the out buffer the output is to start at.- Throws:
DataLengthException
- if there isn't enough space in out.java.lang.IllegalStateException
- if the MAC is not initialised.
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