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Spongy Castle is a package-rename (org.bouncycastle.* to org.spongycastle.*) of Bouncy Castle intended for Android.
Android ships with a stripped-down version of Bouncy Castle - this causes classloader collisions if you try to add
an alternative (updated/complete) Bouncy Castle jar.
This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5.
package org.spongycastle.crypto.generators;
import org.spongycastle.crypto.params.GOST3410Parameters;
import org.spongycastle.crypto.params.GOST3410ValidationParameters;
import java.math.BigInteger;
import java.security.SecureRandom;
/**
* generate suitable parameters for GOST3410.
*/
public class GOST3410ParametersGenerator
{
private int size;
private int typeproc;
private SecureRandom init_random;
private static final BigInteger ONE = BigInteger.valueOf(1);
private static final BigInteger TWO = BigInteger.valueOf(2);
/**
* initialise the key generator.
*
* @param size size of the key
* @param typeproc type procedure A,B = 1; A',B' - else
* @param random random byte source.
*/
public void init(
int size,
int typeproc,
SecureRandom random)
{
this.size = size;
this.typeproc = typeproc;
this.init_random = random;
}
//Procedure A
private int procedure_A(int x0, int c, BigInteger[] pq, int size)
{
//Verify and perform condition: 065536)
{
x0 = init_random.nextInt()/32768;
}
while((c<0 || c>65536) || (c/2==0))
{
c = init_random.nextInt()/32768 + 1;
}
BigInteger C = new BigInteger(Integer.toString(c));
BigInteger constA16 = new BigInteger("19381");
//step1
BigInteger[] y = new BigInteger[1]; // begin length = 1
y[0] = new BigInteger(Integer.toString(x0));
//step 2
int[] t = new int[1]; // t - orders; begin length = 1
t[0] = size;
int s = 0;
for (int i=0; t[i]>=17; i++)
{
// extension array t
int tmp_t[] = new int[t.length + 1]; ///////////////
System.arraycopy(t,0,tmp_t,0,t.length); // extension
t = new int[tmp_t.length]; // array t
System.arraycopy(tmp_t, 0, t, 0, tmp_t.length); ///////////////
t[i+1] = t[i]/2;
s = i+1;
}
//step3
BigInteger p[] = new BigInteger[s+1];
p[s] = new BigInteger("8003",16); //set min prime number length 16 bit
int m = s-1; //step4
for (int i=0; i=0)
{
break; //step 14
}
else
{
pq[0] = p[0];
pq[1] = p[1];
return y[0].intValue(); //return for procedure B step 2
}
}
}
return y[0].intValue();
}
//Procedure A'
private long procedure_Aa(long x0, long c, BigInteger[] pq, int size)
{
//Verify and perform condition: 04294967296L)
{
x0 = init_random.nextInt()*2;
}
while((c<0 || c>4294967296L) || (c/2==0))
{
c = init_random.nextInt()*2+1;
}
BigInteger C = new BigInteger(Long.toString(c));
BigInteger constA32 = new BigInteger("97781173");
//step1
BigInteger[] y = new BigInteger[1]; // begin length = 1
y[0] = new BigInteger(Long.toString(x0));
//step 2
int[] t = new int[1]; // t - orders; begin length = 1
t[0] = size;
int s = 0;
for (int i=0; t[i]>=33; i++)
{
// extension array t
int tmp_t[] = new int[t.length + 1]; ///////////////
System.arraycopy(t,0,tmp_t,0,t.length); // extension
t = new int[tmp_t.length]; // array t
System.arraycopy(tmp_t, 0, t, 0, tmp_t.length); ///////////////
t[i+1] = t[i]/2;
s = i+1;
}
//step3
BigInteger p[] = new BigInteger[s+1];
p[s] = new BigInteger("8000000B",16); //set min prime number length 32 bit
int m = s-1; //step4
for (int i=0; i=0)
{
break; //step 14
}
else
{
pq[0] = p[0];
pq[1] = p[1];
return y[0].longValue(); //return for procedure B' step 2
}
}
}
return y[0].longValue();
}
//Procedure B
private void procedure_B(int x0, int c, BigInteger[] pq)
{
//Verify and perform condition: 065536)
{
x0 = init_random.nextInt()/32768;
}
while((c<0 || c>65536) || (c/2==0))
{
c = init_random.nextInt()/32768 + 1;
}
BigInteger [] qp = new BigInteger[2];
BigInteger q = null, Q = null, p = null;
BigInteger C = new BigInteger(Integer.toString(c));
BigInteger constA16 = new BigInteger("19381");
//step1
x0 = procedure_A(x0, c, qp, 256);
q = qp[0];
//step2
x0 = procedure_A(x0, c, qp, 512);
Q = qp[0];
BigInteger[] y = new BigInteger[65];
y[0] = new BigInteger(Integer.toString(x0));
int tp = 1024;
step3: for(;;)
{
//step 3
for (int j=0; j<64; j++)
{
y[j+1] = (y[j].multiply(constA16).add(C)).mod(TWO.pow(16));
}
//step 4
BigInteger Y = new BigInteger("0");
for (int j=0; j<64; j++)
{
Y = Y.add(y[j].multiply(TWO.pow(16*j)));
}
y[0] = y[64]; //step 5
//step 6
BigInteger N = TWO.pow(tp-1).divide(q.multiply(Q)).
add((TWO.pow(tp-1).multiply(Y)).
divide(q.multiply(Q).multiply(TWO.pow(1024))));
if (N.mod(TWO).compareTo(ONE)==0)
{
N = N.add(ONE);
}
int k = 0; //step 7
step8: for(;;)
{
//step 11
p = q.multiply(Q).multiply(N.add(BigInteger.valueOf(k))).add(ONE);
if (p.compareTo(TWO.pow(tp))==1)
{
continue step3; //step 9
}
//step10
if ((TWO.modPow(q.multiply(Q).multiply(N.add(BigInteger.valueOf(k))),p).compareTo(ONE)==0) &&
(TWO.modPow(q.multiply(N.add(BigInteger.valueOf(k))),p).compareTo(ONE)!=0))
{
pq[0] = p;
pq[1] = q;
return;
}
else
{
k += 2;
continue step8;
}
}
}
}
//Procedure B'
private void procedure_Bb(long x0, long c, BigInteger[] pq)
{
//Verify and perform condition: 04294967296L)
{
x0 = init_random.nextInt()*2;
}
while((c<0 || c>4294967296L) || (c/2==0))
{
c = init_random.nextInt()*2+1;
}
BigInteger [] qp = new BigInteger[2];
BigInteger q = null, Q = null, p = null;
BigInteger C = new BigInteger(Long.toString(c));
BigInteger constA32 = new BigInteger("97781173");
//step1
x0 = procedure_Aa(x0, c, qp, 256);
q = qp[0];
//step2
x0 = procedure_Aa(x0, c, qp, 512);
Q = qp[0];
BigInteger[] y = new BigInteger[33];
y[0] = new BigInteger(Long.toString(x0));
int tp = 1024;
step3: for(;;)
{
//step 3
for (int j=0; j<32; j++)
{
y[j+1] = (y[j].multiply(constA32).add(C)).mod(TWO.pow(32));
}
//step 4
BigInteger Y = new BigInteger("0");
for (int j=0; j<32; j++)
{
Y = Y.add(y[j].multiply(TWO.pow(32*j)));
}
y[0] = y[32]; //step 5
//step 6
BigInteger N = TWO.pow(tp-1).divide(q.multiply(Q)).
add((TWO.pow(tp-1).multiply(Y)).
divide(q.multiply(Q).multiply(TWO.pow(1024))));
if (N.mod(TWO).compareTo(ONE)==0)
{
N = N.add(ONE);
}
int k = 0; //step 7
step8: for(;;)
{
//step 11
p = q.multiply(Q).multiply(N.add(BigInteger.valueOf(k))).add(ONE);
if (p.compareTo(TWO.pow(tp))==1)
{
continue step3; //step 9
}
//step10
if ((TWO.modPow(q.multiply(Q).multiply(N.add(BigInteger.valueOf(k))),p).compareTo(ONE)==0) &&
(TWO.modPow(q.multiply(N.add(BigInteger.valueOf(k))),p).compareTo(ONE)!=0))
{
pq[0] = p;
pq[1] = q;
return;
}
else
{
k += 2;
continue step8;
}
}
}
}
/**
* Procedure C
* procedure generates the a value from the given p,q,
* returning the a value.
*/
private BigInteger procedure_C(BigInteger p, BigInteger q)
{
BigInteger pSub1 = p.subtract(ONE);
BigInteger pSub1DivQ = pSub1.divide(q);
int length = p.bitLength();
for(;;)
{
BigInteger d = new BigInteger(length, init_random);
// 1 < d < p-1
if (d.compareTo(ONE) > 0 && d.compareTo(pSub1) < 0)
{
BigInteger a = d.modPow(pSub1DivQ, p);
if (a.compareTo(ONE) != 0)
{
return a;
}
}
}
}
/**
* which generates the p , q and a values from the given parameters,
* returning the GOST3410Parameters object.
*/
public GOST3410Parameters generateParameters()
{
BigInteger [] pq = new BigInteger[2];
BigInteger q = null, p = null, a = null;
int x0, c;
long x0L, cL;
if (typeproc==1)
{
x0 = init_random.nextInt();
c = init_random.nextInt();
switch(size)
{
case 512:
procedure_A(x0, c, pq, 512);
break;
case 1024:
procedure_B(x0, c, pq);
break;
default:
throw new IllegalArgumentException("Ooops! key size 512 or 1024 bit.");
}
p = pq[0]; q = pq[1];
a = procedure_C(p, q);
//System.out.println("p:"+p.toString(16)+"\n"+"q:"+q.toString(16)+"\n"+"a:"+a.toString(16));
//System.out.println("p:"+p+"\n"+"q:"+q+"\n"+"a:"+a);
return new GOST3410Parameters(p, q, a, new GOST3410ValidationParameters(x0, c));
}
else
{
x0L = init_random.nextLong();
cL = init_random.nextLong();
switch(size)
{
case 512:
procedure_Aa(x0L, cL, pq, 512);
break;
case 1024:
procedure_Bb(x0L, cL, pq);
break;
default:
throw new IllegalStateException("Ooops! key size 512 or 1024 bit.");
}
p = pq[0]; q = pq[1];
a = procedure_C(p, q);
//System.out.println("p:"+p.toString(16)+"\n"+"q:"+q.toString(16)+"\n"+"a:"+a.toString(16));
//System.out.println("p:"+p+"\n"+"q:"+q+"\n"+"a:"+a);
return new GOST3410Parameters(p, q, a, new GOST3410ValidationParameters(x0L, cL));
}
}
}