bouncycastle: Android tree with upstream code for version 1.50

Android tree as of c0d8909a6c6a4ac075a9dee7ac1fe6baff34acc0

Change-Id: I8d381554d6edec32aae8ff5bab5d5314f0954440

1 files changed, 11 insertions, 5 deletions

diff --git a/bcprov/src/main/java/org/bouncycastle/crypto/agreement/ECDHCBasicAgreement.java b/bcprov/src/main/java/org/bouncycastle/crypto/agreement/ECDHCBasicAgreement.java
index 12b8405..28140df 100644
--- a/bcprov/src/main/java/org/bouncycastle/crypto/agreement/ECDHCBasicAgreement.java
+++ b/bcprov/src/main/java/org/bouncycastle/crypto/agreement/ECDHCBasicAgreement.java
@@ -47,12 +47,18 @@ public class ECDHCBasicAgreement
     public BigInteger calculateAgreement(
         CipherParameters pubKey)
     {
-        ECPublicKeyParameters   pub = (ECPublicKeyParameters)pubKey;
-        ECDomainParameters      params = pub.getParameters();
-        ECPoint P = pub.getQ().multiply(params.getH().multiply(key.getD()));
+        ECPublicKeyParameters pub = (ECPublicKeyParameters)pubKey;
+        ECDomainParameters params = pub.getParameters();
 
-        // if (p.isInfinity()) throw new RuntimeException("Invalid public key");
+        BigInteger hd = params.getH().multiply(key.getD()).mod(params.getN());
 
-        return P.getX().toBigInteger();
+        ECPoint P = pub.getQ().multiply(hd).normalize();
+
+        if (P.isInfinity())
+        {
+            throw new IllegalStateException("Infinity is not a valid agreement value for ECDHC");
+        }
+
+        return P.getAffineXCoord().toBigInteger();
     }
 }