gnu.crypto.hash
Class Sha160
- Cloneable, IMessageDigest
The Secure Hash Algorithm (SHA-1) is required for use with the Digital
Signature Algorithm (DSA) as specified in the Digital Signature Standard
(DSS) and whenever a secure hash algorithm is required for federal
applications. For a message of length less than 2^64 bits, the SHA-1
produces a 160-bit condensed representation of the message called a message
digest. The message digest is used during generation of a signature for the
message. The SHA-1 is also used to compute a message digest for the received
version of the message during the process of verifying the signature. Any
change to the message in transit will, with very high probability, result in
a different message digest, and the signature will fail to verify.
The SHA-1 is designed to have the following properties: it is
computationally infeasible to find a message which corresponds to a given
message digest, or to find two different messages which produce the same
message digest.
References:
- SECURE HASH
STANDARD
Federal Information, Processing Standards Publication 180-1, 1995 April 17.
Sha160() - Trivial 0-arguments constructor.
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static int[] | G(int hh0, int hh1, int hh2, int hh3, int hh4, byte[] in, int offset)
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Object | clone() - Returns a clone copy of this instance.
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protected byte[] | getResult() - Constructs the result from the contents of the current context.
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protected byte[] | padBuffer() - Returns the byte array to use as padding before completing a hash
operation.
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protected void | resetContext() - Resets the instance for future re-use.
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boolean | selfTest() - A basic test.
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protected void | transform(byte[] in, int offset) - The block digest transformation per se.
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blockSize , clone , digest , getResult , hashSize , name , padBuffer , reset , resetContext , selfTest , transform , update , update , update |
Sha160
public Sha160()
Trivial 0-arguments constructor.
G
public static final int[] G(int hh0,
int hh1,
int hh2,
int hh3,
int hh4,
byte[] in,
int offset)
getResult
protected byte[] getResult()
Constructs the result from the contents of the current context.
- getResult in interface BaseHash
- the output of the completed hash operation.
padBuffer
protected byte[] padBuffer()
Returns the byte array to use as padding before completing a hash
operation.
- padBuffer in interface BaseHash
- the bytes to pad the remaining bytes in the buffer before
completing a hash operation.
resetContext
protected void resetContext()
Resets the instance for future re-use.
- resetContext in interface BaseHash
selfTest
public boolean selfTest()
A basic test. Ensures that the digest of a pre-determined message is equal
to a known pre-computed value.
- selfTest in interface IMessageDigest
- selfTest in interface BaseHash
- true if the implementation passes a basic self-test.
Returns false otherwise.
transform
protected void transform(byte[] in,
int offset)
The block digest transformation per se.
- transform in interface BaseHash
in
- the blockSize long block, as an array of bytes to digest.offset
- the index where the data to digest is located within the
input buffer.
Copyright © 2001, 2002, 2003
Free Software Foundation,
Inc. All Rights Reserved.