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ElGamal: Implement key encoding

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This commit is contained in:
zzz
2016-01-24 21:40:33 +00:00
parent f38cfcc937
commit ed9d403281
3 changed files with 123 additions and 3 deletions
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2
core/java/src/net/i2p/crypto/SigUtil.java
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@ -716,7 +716,7 @@ public final class SigUtil {
* @return the new index
* @since 0.9.25
*/
private static int intToASN1(byte[] d, int idx, int val) {
public static int intToASN1(byte[] d, int idx, int val) {
if (val < 0 || val > 65535)
throw new IllegalArgumentException("fixme length " + val);
if (val > 127) {

59
core/java/src/net/i2p/crypto/elgamal/impl/ElGamalPrivateKeyImpl.java
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@ -10,7 +10,9 @@ import javax.crypto.interfaces.DHPrivateKey;
import javax.crypto.spec.DHParameterSpec;
import javax.crypto.spec.DHPrivateKeySpec;
import static net.i2p.crypto.SigUtil.intToASN1;
import net.i2p.crypto.elgamal.ElGamalPrivateKey;
import static net.i2p.crypto.elgamal.impl.ElGamalPublicKeyImpl.spaceFor;
import net.i2p.crypto.elgamal.spec.ElGamalParameterSpec;
import net.i2p.crypto.elgamal.spec.ElGamalPrivateKeySpec;
@ -93,7 +95,62 @@ public class ElGamalPrivateKeyImpl
*/
public byte[] getEncoded()
{
return null;
byte[] pb = elSpec.getP().toByteArray();
byte[] gb = elSpec.getG().toByteArray();
byte[] xb = x.toByteArray();
int seq3len = 2 + spaceFor(pb.length) + spaceFor(gb.length);
int seq2len = 8 + 1 + spaceFor(seq3len);
int seq1len = 1 + 3 + spaceFor(seq2len) + 1 + spaceFor(xb.length);
int totlen = 1 + spaceFor(seq1len);
byte[] rv = new byte[totlen];
int idx = 0;
// sequence 1
rv[idx++] = 0x30;
idx = intToASN1(rv, idx, seq1len);
// version
rv[idx++] = 0x02;
rv[idx++] = 1;
rv[idx++] = 0;
// Algorithm Identifier
// sequence 2
rv[idx++] = 0x30;
idx = intToASN1(rv, idx, seq2len);
// OID: 1.3.14.7.2.1.1
rv[idx++] = 0x06;
rv[idx++] = 6;
rv[idx++] = (1 * 40) + 3;
rv[idx++] = 14;
rv[idx++] = 7;
rv[idx++] = 2;
rv[idx++] = 1;
rv[idx++] = 1;
// params
// sequence 3
rv[idx++] = 0x30;
idx = intToASN1(rv, idx, seq3len);
// P
// integer
rv[idx++] = 0x02;
idx = intToASN1(rv, idx, pb.length);
System.arraycopy(pb, 0, rv, idx, pb.length);
idx += pb.length;
// G
// integer
rv[idx++] = 0x02;
idx = intToASN1(rv, idx, gb.length);
System.arraycopy(gb, 0, rv, idx, gb.length);
idx += gb.length;
// the key
// octet string
rv[idx++] = 0x04;
idx = intToASN1(rv, idx, xb.length);
// BC puts an integer in the bit string, we're not going to do that
System.arraycopy(xb, 0, rv, idx, xb.length);
return rv;
}
public ElGamalParameterSpec getParameters()

65
core/java/src/net/i2p/crypto/elgamal/impl/ElGamalPublicKeyImpl.java
View File

@ -10,6 +10,7 @@ import javax.crypto.interfaces.DHPublicKey;
import javax.crypto.spec.DHParameterSpec;
import javax.crypto.spec.DHPublicKeySpec;
import static net.i2p.crypto.SigUtil.intToASN1;
import net.i2p.crypto.elgamal.ElGamalPublicKey;
import net.i2p.crypto.elgamal.spec.ElGamalParameterSpec;
import net.i2p.crypto.elgamal.spec.ElGamalPublicKeySpec;
@ -78,7 +79,69 @@ public class ElGamalPublicKeyImpl
public byte[] getEncoded()
{
return null;
byte[] pb = elSpec.getP().toByteArray();
byte[] gb = elSpec.getG().toByteArray();
byte[] yb = y.toByteArray();
int seq3len = 2 + spaceFor(pb.length) + spaceFor(gb.length);
int seq2len = 8 + 1 + spaceFor(seq3len);
int seq1len = 1 + spaceFor(seq2len) + 1 + spaceFor(yb.length + 1);
int totlen = 1 + spaceFor(seq1len);
byte[] rv = new byte[totlen];
int idx = 0;
// sequence 1
rv[idx++] = 0x30;
idx = intToASN1(rv, idx, seq1len);
// Algorithm Identifier
// sequence 2
rv[idx++] = 0x30;
idx = intToASN1(rv, idx, seq2len);
// OID: 1.3.14.7.2.1.1
rv[idx++] = 0x06;
rv[idx++] = 6;
rv[idx++] = (1 * 40) + 3;
rv[idx++] = 14;
rv[idx++] = 7;
rv[idx++] = 2;
rv[idx++] = 1;
rv[idx++] = 1;
// params
// sequence 3
rv[idx++] = 0x30;
idx = intToASN1(rv, idx, seq3len);
// P
// integer
rv[idx++] = 0x02;
idx = intToASN1(rv, idx, pb.length);
System.arraycopy(pb, 0, rv, idx, pb.length);
idx += pb.length;
// G
// integer
rv[idx++] = 0x02;
idx = intToASN1(rv, idx, gb.length);
System.arraycopy(gb, 0, rv, idx, gb.length);
idx += gb.length;
// the key
// bit string
rv[idx++] = 0x03;
idx = intToASN1(rv, idx, yb.length + 1);
rv[idx++] = 0; // number of trailing unused bits
// BC puts an integer in the bit string, we're not going to do that
System.arraycopy(yb, 0, rv, idx, yb.length);
return rv;
}
static int spaceFor(int val) {
int rv;
if (val > 255)
rv = 3;
else if (val > 127)
rv = 2;
else
rv = 1;
return rv + val;
}
public ElGamalParameterSpec getParameters()