public class DSSSignature extends BaseSignature
The DSS (Digital Signature Standard) algorithm makes use of the following parameters:
2L-1 < p < 2L
for 512 <= L <= 1024 and L a
multiple of 64.p - 1, where 2159
< q < 2160.g = h(p-1)/q mod p, where
h is any integer with 1 < h < p - 1 such
that h (p-1)/q mod p > 1 (g has order
q mod p).0 < x
< q.y = gx mod p.0 < k
< q.The integers p, q, and g can be
public and can be common to a group of users. A user's private and public
keys are x and y, respectively. They are normally
fixed for a period of time. Parameters x and k are
used for signature generation only, and must be kept secret. Parameter
k must be regenerated for each signature.
The signature of a message M is the pair of numbers r
and s computed according to the equations below:
r = (gk mod p) mod q ands = (k-1(SHA(M) + xr)) mod q.In the above, k-1 is the multiplicative inverse of
k, mod q; i.e., (k-1 k) mod q = 1
and 0 < k-1 < q. The value of SHA(M)
is a 160-bit string output by the Secure Hash Algorithm specified in FIPS 180.
For use in computing s, this string must be converted to an
integer.
As an option, one may wish to check if r == 0 or s == 0
. If either r == 0 or s == 0, a new value
of k should be generated and the signature should be
recalculated (it is extremely unlikely that r == 0 or s ==
0 if signatures are generated properly).
The signature is transmitted along with the message to the verifier.
References:
md, privateKey, publicKey, schemeNameSIGNER_KEY, SOURCE_OF_RANDOMNESS, VERIFIER_KEY| Constructor and Description |
|---|
DSSSignature()
Trivial 0-arguments constructor.
|
| Modifier and Type | Method and Description |
|---|---|
java.lang.Object |
clone()
Returns a clone copy of this instance.
|
protected java.lang.Object |
generateSignature() |
protected void |
setupForSigning(java.security.PrivateKey k) |
protected void |
setupForVerification(java.security.PublicKey k) |
static java.math.BigInteger[] |
sign(java.security.interfaces.DSAPrivateKey k,
byte[] h) |
static java.math.BigInteger[] |
sign(java.security.interfaces.DSAPrivateKey k,
byte[] h,
tr.gov.tubitak.uekae.esya.api.common.crypto.IRandom irnd) |
static java.math.BigInteger[] |
sign(java.security.interfaces.DSAPrivateKey k,
byte[] h,
java.util.Random rnd) |
static boolean |
verify(java.security.interfaces.DSAPublicKey k,
byte[] h,
java.math.BigInteger[] rs) |
protected boolean |
verifySignature(java.lang.Object sig) |
clearData, clearData, init, name, nextRandomBytes, setupSign, setupVerify, sign, update, update, verifypublic static final java.math.BigInteger[] sign(java.security.interfaces.DSAPrivateKey k,
byte[] h)
public static final java.math.BigInteger[] sign(java.security.interfaces.DSAPrivateKey k,
byte[] h,
java.util.Random rnd)
public static final java.math.BigInteger[] sign(java.security.interfaces.DSAPrivateKey k,
byte[] h,
tr.gov.tubitak.uekae.esya.api.common.crypto.IRandom irnd)
public static final boolean verify(java.security.interfaces.DSAPublicKey k,
byte[] h,
java.math.BigInteger[] rs)
public java.lang.Object clone()
ISignatureReturns a clone copy of this instance.
clone in interface ISignatureclone in class BaseSignatureprotected void setupForVerification(java.security.PublicKey k)
throws java.lang.IllegalArgumentException
setupForVerification in class BaseSignaturejava.lang.IllegalArgumentExceptionprotected void setupForSigning(java.security.PrivateKey k)
throws java.lang.IllegalArgumentException
setupForSigning in class BaseSignaturejava.lang.IllegalArgumentExceptionprotected java.lang.Object generateSignature()
throws java.lang.IllegalStateException
generateSignature in class BaseSignaturejava.lang.IllegalStateExceptionprotected boolean verifySignature(java.lang.Object sig)
throws java.lang.IllegalStateException
verifySignature in class BaseSignaturejava.lang.IllegalStateExceptionCopyright © 2025. All rights reserved.