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java.lang.Object
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+--gnu.crypto.hash.BaseHash
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+--gnu.crypto.hash.Sha160
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:
| Field Summary |
| Fields inherited from class gnu.crypto.hash.BaseHash |
blockSize, buffer, count, hashSize, name |
| Constructor Summary | |
Sha160()
Trivial 0-arguments constructor. |
|
| Method Summary | |
java.lang.Object |
clone()
Returns a clone copy of this instance. |
static int[] |
G(int hh0,
int hh1,
int hh2,
int hh3,
int hh4,
byte[] in,
int offset)
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protected byte[] |
getResult()
Constructs the result from the contents of the current context. |
protected byte[] |
padBuffer()
Returns the byte array to use as padding before completing a hash operation. |
protected void |
resetContext()
Resets the instance for future re-use. |
boolean |
selfTest()
A basic test. |
protected void |
transform(byte[] in,
int offset)
The block digest transformation per se. |
| Methods inherited from class gnu.crypto.hash.BaseHash |
blockSize, digest, hashSize, name, reset, update, update |
| Methods inherited from class java.lang.Object |
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
public Sha160()
| Method Detail |
public static final int[] G(int hh0,
int hh1,
int hh2,
int hh3,
int hh4,
byte[] in,
int offset)
public java.lang.Object clone()
IMessageDigestReturns a clone copy of this instance.
clone in interface IMessageDigestclone in class BaseHash
protected void transform(byte[] in,
int offset)
BaseHashThe block digest transformation per se.
transform in class BaseHashin - 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.protected byte[] padBuffer()
BaseHashReturns the byte array to use as padding before completing a hash operation.
padBuffer in class BaseHashprotected byte[] getResult()
BaseHashConstructs the result from the contents of the current context.
getResult in class BaseHashprotected void resetContext()
BaseHash
resetContext in class BaseHashpublic boolean selfTest()
IMessageDigestA basic test. Ensures that the digest of a pre-determined message is equal to a known pre-computed value.
selfTest in interface IMessageDigestselfTest in class BaseHash
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