Mercurial > 510Connectbot
view app/src/main/java/ch/ethz/ssh2/crypto/dh/DhGroupExchange.java @ 489:b257517e9bef
Added tag stable-1.9.4-1 for changeset 869070df0e80
author | Carl Byington <carl@five-ten-sg.com> |
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date | Wed, 14 Oct 2020 12:26:53 -0700 |
parents | d29cce60f393 |
children |
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package ch.ethz.ssh2.crypto.dh; import java.math.BigInteger; import java.security.SecureRandom; import java.io.IOException; import ch.ethz.ssh2.DHGexParameters; import ch.ethz.ssh2.crypto.digest.HashForSSH2Types; /** * DhGroupExchange. * * @author Christian Plattner, plattner@trilead.com * @version $Id: DhGroupExchange.java,v 1.1 2007/10/15 12:49:57 cplattne Exp $ */ public class DhGroupExchange { /* Given by the standard */ private BigInteger p; private BigInteger g; /* Client public and private */ private BigInteger e; private BigInteger x; /* Server public */ private BigInteger f; /* Shared secret */ private BigInteger k; public DhGroupExchange(BigInteger p, BigInteger g) { this.p = p; this.g = g; } public void init(SecureRandom rnd) { k = null; x = new BigInteger(p.bitLength() - 1, rnd); e = g.modPow(x, p); } /** * @return Returns the e. */ public BigInteger getE() { if (e == null) throw new IllegalStateException("Not initialized!"); return e; } /** * @return Returns the shared secret k. */ public BigInteger getK() { if (k == null) throw new IllegalStateException("Shared secret not yet known, need f first!"); return k; } /** * Sets f and calculates the shared secret. */ public void setF(BigInteger f) { if (e == null) throw new IllegalStateException("Not initialized!"); BigInteger zero = BigInteger.valueOf(0); if (zero.compareTo(f) >= 0 || p.compareTo(f) <= 0) throw new IllegalArgumentException("Invalid f specified!"); this.f = f; this.k = f.modPow(x, p); } public byte[] calculateH(String hashAlgo, byte[] clientversion, byte[] serverversion, byte[] clientKexPayload, byte[] serverKexPayload, byte[] hostKey, DHGexParameters para) throws IOException { HashForSSH2Types hash = new HashForSSH2Types(hashAlgo); hash.updateByteString(clientversion); hash.updateByteString(serverversion); hash.updateByteString(clientKexPayload); hash.updateByteString(serverKexPayload); hash.updateByteString(hostKey); if (para.getMin_group_len() > 0) hash.updateUINT32(para.getMin_group_len()); hash.updateUINT32(para.getPref_group_len()); if (para.getMax_group_len() > 0) hash.updateUINT32(para.getMax_group_len()); hash.updateBigInt(p); hash.updateBigInt(g); hash.updateBigInt(e); hash.updateBigInt(f); hash.updateBigInt(k); return hash.getDigest(); } }