diff options
Diffstat (limited to 'src/com/trilead/ssh2/signature/DSASHA1Verify.java')
| -rw-r--r-- | src/com/trilead/ssh2/signature/DSASHA1Verify.java | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/src/com/trilead/ssh2/signature/DSASHA1Verify.java b/src/com/trilead/ssh2/signature/DSASHA1Verify.java new file mode 100644 index 0000000..04c4b20 --- /dev/null +++ b/src/com/trilead/ssh2/signature/DSASHA1Verify.java @@ -0,0 +1,199 @@ +
+package com.trilead.ssh2.signature;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.security.SecureRandom;
+
+import com.trilead.ssh2.crypto.digest.SHA1;
+import com.trilead.ssh2.log.Logger;
+import com.trilead.ssh2.packets.TypesReader;
+import com.trilead.ssh2.packets.TypesWriter;
+
+
+/**
+ * DSASHA1Verify.
+ *
+ * @author Christian Plattner, plattner@trilead.com
+ * @version $Id: DSASHA1Verify.java,v 1.1 2007/10/15 12:49:57 cplattne Exp $
+ */
+public class DSASHA1Verify
+{
+ private static final Logger log = Logger.getLogger(DSASHA1Verify.class);
+
+ public static DSAPublicKey decodeSSHDSAPublicKey(byte[] key) throws IOException
+ {
+ TypesReader tr = new TypesReader(key);
+
+ String key_format = tr.readString();
+
+ if (key_format.equals("ssh-dss") == false)
+ throw new IllegalArgumentException("This is not a ssh-dss public key!");
+
+ BigInteger p = tr.readMPINT();
+ BigInteger q = tr.readMPINT();
+ BigInteger g = tr.readMPINT();
+ BigInteger y = tr.readMPINT();
+
+ if (tr.remain() != 0)
+ throw new IOException("Padding in DSA public key!");
+
+ return new DSAPublicKey(p, q, g, y);
+ }
+
+ public static byte[] encodeSSHDSAPublicKey(DSAPublicKey pk) throws IOException
+ {
+ TypesWriter tw = new TypesWriter();
+
+ tw.writeString("ssh-dss");
+ tw.writeMPInt(pk.getP());
+ tw.writeMPInt(pk.getQ());
+ tw.writeMPInt(pk.getG());
+ tw.writeMPInt(pk.getY());
+
+ return tw.getBytes();
+ }
+
+ public static byte[] encodeSSHDSASignature(DSASignature ds)
+ {
+ TypesWriter tw = new TypesWriter();
+
+ tw.writeString("ssh-dss");
+
+ byte[] r = ds.getR().toByteArray();
+ byte[] s = ds.getS().toByteArray();
+
+ byte[] a40 = new byte[40];
+
+ /* Patch (unsigned) r and s into the target array. */
+
+ int r_copylen = (r.length < 20) ? r.length : 20;
+ int s_copylen = (s.length < 20) ? s.length : 20;
+
+ System.arraycopy(r, r.length - r_copylen, a40, 20 - r_copylen, r_copylen);
+ System.arraycopy(s, s.length - s_copylen, a40, 40 - s_copylen, s_copylen);
+
+ tw.writeString(a40, 0, 40);
+
+ return tw.getBytes();
+ }
+
+ public static DSASignature decodeSSHDSASignature(byte[] sig) throws IOException
+ {
+ TypesReader tr = new TypesReader(sig);
+
+ String sig_format = tr.readString();
+
+ if (sig_format.equals("ssh-dss") == false)
+ throw new IOException("Peer sent wrong signature format");
+
+ byte[] rsArray = tr.readByteString();
+
+ if (rsArray.length != 40)
+ throw new IOException("Peer sent corrupt signature");
+
+ if (tr.remain() != 0)
+ throw new IOException("Padding in DSA signature!");
+
+ /* Remember, s and r are unsigned ints. */
+
+ byte[] tmp = new byte[20];
+
+ System.arraycopy(rsArray, 0, tmp, 0, 20);
+ BigInteger r = new BigInteger(1, tmp);
+
+ System.arraycopy(rsArray, 20, tmp, 0, 20);
+ BigInteger s = new BigInteger(1, tmp);
+
+ if (log.isEnabled())
+ {
+ log.log(30, "decoded ssh-dss signature: first bytes r(" + ((rsArray[0]) & 0xff) + "), s("
+ + ((rsArray[20]) & 0xff) + ")");
+ }
+
+ return new DSASignature(r, s);
+ }
+
+ public static boolean verifySignature(byte[] message, DSASignature ds, DSAPublicKey dpk) throws IOException
+ {
+ /* Inspired by Bouncycastle's DSASigner class */
+
+ SHA1 md = new SHA1();
+ md.update(message);
+ byte[] sha_message = new byte[md.getDigestLength()];
+ md.digest(sha_message);
+
+ BigInteger m = new BigInteger(1, sha_message);
+
+ BigInteger r = ds.getR();
+ BigInteger s = ds.getS();
+
+ BigInteger g = dpk.getG();
+ BigInteger p = dpk.getP();
+ BigInteger q = dpk.getQ();
+ BigInteger y = dpk.getY();
+
+ BigInteger zero = BigInteger.ZERO;
+
+ if (log.isEnabled())
+ {
+ log.log(60, "ssh-dss signature: m: " + m.toString(16));
+ log.log(60, "ssh-dss signature: r: " + r.toString(16));
+ log.log(60, "ssh-dss signature: s: " + s.toString(16));
+ log.log(60, "ssh-dss signature: g: " + g.toString(16));
+ log.log(60, "ssh-dss signature: p: " + p.toString(16));
+ log.log(60, "ssh-dss signature: q: " + q.toString(16));
+ log.log(60, "ssh-dss signature: y: " + y.toString(16));
+ }
+
+ if (zero.compareTo(r) >= 0 || q.compareTo(r) <= 0)
+ {
+ log.log(20, "ssh-dss signature: zero.compareTo(r) >= 0 || q.compareTo(r) <= 0");
+ return false;
+ }
+
+ if (zero.compareTo(s) >= 0 || q.compareTo(s) <= 0)
+ {
+ log.log(20, "ssh-dss signature: zero.compareTo(s) >= 0 || q.compareTo(s) <= 0");
+ return false;
+ }
+
+ BigInteger w = s.modInverse(q);
+
+ BigInteger u1 = m.multiply(w).mod(q);
+ BigInteger u2 = r.multiply(w).mod(q);
+
+ u1 = g.modPow(u1, p);
+ u2 = y.modPow(u2, p);
+
+ BigInteger v = u1.multiply(u2).mod(p).mod(q);
+
+ return v.equals(r);
+ }
+
+ public static DSASignature generateSignature(byte[] message, DSAPrivateKey pk, SecureRandom rnd)
+ {
+ SHA1 md = new SHA1();
+ md.update(message);
+ byte[] sha_message = new byte[md.getDigestLength()];
+ md.digest(sha_message);
+
+ BigInteger m = new BigInteger(1, sha_message);
+ BigInteger k;
+ int qBitLength = pk.getQ().bitLength();
+
+ do
+ {
+ k = new BigInteger(qBitLength, rnd);
+ }
+ while (k.compareTo(pk.getQ()) >= 0);
+
+ BigInteger r = pk.getG().modPow(k, pk.getP()).mod(pk.getQ());
+
+ k = k.modInverse(pk.getQ()).multiply(m.add((pk).getX().multiply(r)));
+
+ BigInteger s = k.mod(pk.getQ());
+
+ return new DSASignature(r, s);
+ }
+}
|