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for one protocol's verification

lping9188

发贴: 0
积分: 0

于 2003-03-11 19:43

Hi,
I want to implement one protocol, which used the verifciation: Be given a multiplicative of a random number and a signed data, then decrypt the multiplicative by using public key, the result should be equal to a multiplicative of the hash data and the encrypted data of the reandom number by public key.
I made such a programme, if I replace hash value by another byte[] data,it success, but when use hash value, it always failed.

MessageDigest md= MessageDigest.getInstance("SHA-1");
md.update("data".getBytes());
byte[] hash= md.digest();

/* if I use that one replace the hash value, it success;
byte[] hash="MessageDigest md= MessageDigest.getInstance;".getBytes();*/

Cipher c = Cipher.getInstance("RSA","BC");
c.init(Cipher.ENCRYPT_MODE,pri1);
byte[] encrypted = c.doFinal(hash);

BigInteger encryptedbig=new BigInteger(encrypted);

byte[] r="6".getBytes(); //just take as a random number;

BigInteger rbig=new BigInteger(r);

BigInteger Xb=rbig.multiply(encryptedbig);

BigInteger XB=Xb.modPow(exp1,n1);

BigInteger XBm=XB.mod(n1);
RSAKeyGenParameterSpec para=new RSAKeyGenParameterSpec(2048,exp1);

KeyPairGenerator kg2 = KeyPairGenerator.getInstance("RSA","BC");
kg2.initialize(para);
KeyPair kp2 = kg2.generateKeyPair();

RSAPrivateCrtKey pri2 = ( RSAPrivateCrtKey) kp2.getPrivate();

RSAPublicKey pub2 = ( RSAPublicKey) kp2.getPublic();

BigInteger n2=pub2.getModulus();

BigInteger n3=n1.multiply(n2);
BigInteger Yb=rbig.modPow(exp1,n3);
BigInteger Ybb=rbig.modPow(exp1,n1);

BigInteger Yb1=Yb.mod(n1);

BigInteger hashbig=new BigInteger(hash);

BigInteger Ybbig=hashbig.multiply(Yb1);

BigInteger Ybbb=Ybbig.mod(n1);

if(XBm.equals(Ybbb))
{
System.out.println("Success");
}
else
{

System.out.println("Failed");
}

作者	Re:for one protocol's verification [Re:lping9188]
floater Java Jedi 总版主发贴: 3233 积分: 421	于 2003-03-19 03:13 I am a little bit confused by your wording. Could you clarify which lines are not working? "Any fool can write code that a computer can understand. Good programmers write code that humans can understand." - Martin Fowler, Refactoring - Improving the Design of Existing Code

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