Merge "Merge remote-tracking branch 'aosp/upstream-master' into merge-152-from-upstream"

1 files changed, 131 insertions, 0 deletions

diff --git a/bcprov/src/main/java/org/bouncycastle/crypto/signers/GOST3410Signer.java b/bcprov/src/main/java/org/bouncycastle/crypto/signers/GOST3410Signer.java
new file mode 100644
index 0000000..135f185
--- /dev/null
+++ b/bcprov/src/main/java/org/bouncycastle/crypto/signers/GOST3410Signer.java
@@ -0,0 +1,131 @@
+package org.bouncycastle.crypto.signers;
+
+import java.math.BigInteger;
+import java.security.SecureRandom;
+
+import org.bouncycastle.crypto.CipherParameters;
+import org.bouncycastle.crypto.DSA;
+import org.bouncycastle.crypto.params.GOST3410KeyParameters;
+import org.bouncycastle.crypto.params.GOST3410Parameters;
+import org.bouncycastle.crypto.params.GOST3410PrivateKeyParameters;
+import org.bouncycastle.crypto.params.GOST3410PublicKeyParameters;
+import org.bouncycastle.crypto.params.ParametersWithRandom;
+
+/**
+ * GOST R 34.10-94 Signature Algorithm
+ */
+public class GOST3410Signer
+        implements DSA
+{
+        GOST3410KeyParameters key;
+
+        SecureRandom    random;
+
+        public void init(
+            boolean                 forSigning,
+            CipherParameters        param)
+        {
+            if (forSigning)
+            {
+                if (param instanceof ParametersWithRandom)
+                {
+                    ParametersWithRandom rParam = (ParametersWithRandom)param;
+
+                    this.random = rParam.getRandom();
+                    this.key = (GOST3410PrivateKeyParameters)rParam.getParameters();
+                }
+                else
+                {
+                    this.random = new SecureRandom();
+                    this.key = (GOST3410PrivateKeyParameters)param;
+                }
+            }
+            else
+            {
+                this.key = (GOST3410PublicKeyParameters)param;
+            }
+        }
+
+        /**
+         * generate a signature for the given message using the key we were
+         * initialised with. For conventional GOST3410 the message should be a GOST3411
+         * hash of the message of interest.
+         *
+         * @param message the message that will be verified later.
+         */
+        public BigInteger[] generateSignature(
+            byte[] message)
+        {
+            byte[] mRev = new byte[message.length]; // conversion is little-endian
+            for (int i = 0; i != mRev.length; i++)
+            {
+                mRev[i] = message[mRev.length - 1 - i];
+            }
+            
+            BigInteger      m = new BigInteger(1, mRev);
+            GOST3410Parameters   params = key.getParameters();
+            BigInteger      k;
+
+            do
+            {
+                k = new BigInteger(params.getQ().bitLength(), random);
+            }
+            while (k.compareTo(params.getQ()) >= 0);
+
+            BigInteger  r = params.getA().modPow(k, params.getP()).mod(params.getQ());
+
+            BigInteger  s = k.multiply(m).
+                                add(((GOST3410PrivateKeyParameters)key).getX().multiply(r)).
+                                    mod(params.getQ());
+
+            BigInteger[]  res = new BigInteger[2];
+
+            res[0] = r;
+            res[1] = s;
+
+            return res;
+        }
+
+        /**
+         * return true if the value r and s represent a GOST3410 signature for
+         * the passed in message for standard GOST3410 the message should be a
+         * GOST3411 hash of the real message to be verified.
+         */
+        public boolean verifySignature(
+            byte[]      message,
+            BigInteger  r,
+            BigInteger  s)
+        {
+            byte[] mRev = new byte[message.length]; // conversion is little-endian
+            for (int i = 0; i != mRev.length; i++)
+            {
+                mRev[i] = message[mRev.length - 1 - i];
+            }
+            
+            BigInteger           m = new BigInteger(1, mRev);
+            GOST3410Parameters params = key.getParameters();
+            BigInteger           zero = BigInteger.valueOf(0);
+
+            if (zero.compareTo(r) >= 0 || params.getQ().compareTo(r) <= 0)
+            {
+                return false;
+            }
+
+            if (zero.compareTo(s) >= 0 || params.getQ().compareTo(s) <= 0)
+            {
+                return false;
+            }
+
+            BigInteger  v = m.modPow(params.getQ().subtract(new BigInteger("2")),params.getQ());
+
+            BigInteger  z1 = s.multiply(v).mod(params.getQ());
+            BigInteger  z2 = (params.getQ().subtract(r)).multiply(v).mod(params.getQ());
+            
+            z1 = params.getA().modPow(z1, params.getP());
+            z2 = ((GOST3410PublicKeyParameters)key).getY().modPow(z2, params.getP());
+
+            BigInteger  u = z1.multiply(z2).mod(params.getP()).mod(params.getQ());
+
+            return u.equals(r);
+        }
+}