Question

 public static void main(String[] args) {
    try{
        String mod = "q0AwozeUj0VVkoksDQSCTj3QEgODomq4sAr02xMyIrWldZrNHhWfZAIcWt2MuAY3X6S3ZVUfOFXOrVbltRrO3F9Z6R8/jJIMv7wjkeVBFC5gncwGR0C3aV9gmF6II19jTKfF1sxb26iMEMAlMEOSnAAceNaJH91zBoaW7ZIh+qk=";
        String exp = "AQAB";
        byte[] modulusBytes = Base64.decodeBase64(mod.getBytes("UTF-8"));
        byte[] exponentBytes = Base64.decodeBase64(exp.getBytes("UTF-8"));
        String signedMessage = "3753e672cfb21e3c182ef2df51f19edeffb63432ed338a47251326ccc14aa63883e910a140cf313754ebc6425aad434e309307cc882da6cd4a4f9f40bd14a9823aca145e5ffc97cd63dbb5925c049282416bdfd7d74ddeef7055065210a841793fe315dff5a44af19c1522daafdc2f7e61ce5a2b42ebf79dfb086e6d210168dd";
        BigInteger modulus = new BigInteger(1, modulusBytes );               
        BigInteger exponent = new BigInteger(1, exponentBytes);
        RSAPublicKeySpec rsaPubKey = new RSAPublicKeySpec(modulus, exponent);
        KeyFactory fact = KeyFactory.getInstance("RSA");
        PublicKey pubKey = fact.generatePublic(rsaPubKey);
        Signature signature = Signature.getInstance("SHA1withRSA");
        byte[] sigBytes = hexStringToByteArray(signedMessage);
        signature.initVerify(pubKey);
        System.out.println(signature.verify(sigBytes));
    }catch(Exception e){
        System.out.println("Error: " + e.toString());
    }
}
private static byte[] hexStringToByteArray(final String encoded) {
    if ((encoded.length() % 2) != 0)
        throw new IllegalArgumentException("Input string must contain an even number of characters");

    final byte result[] = new byte[encoded.length()/2];
    final char enc[] = encoded.toCharArray();
    for (int i = 0; i < enc.length; i += 2) {
        StringBuilder curr = new StringBuilder(2);
        curr.append(enc[i]).append(enc[i + 1]);
        result[i/2] = (byte) Integer.parseInt(curr.toString(), 16);
    }
    return result;
}

此代码始终返回false。我不知道从哪里开始。

Answer 1

在您对邮件进行签名时，您应该拥有以下代码：

Signature signature = Signature.getInstance("SHA1withRSA");
signature.initSign(privKey);
signature.update(message);
byte[] signatureValue = signature.sign();

请注意名为signatureValue的字节数组。这是数据的实际签名。这是您应该为verify() - 方法提供的内容。应该在调用update() - 方法时提供已签名的消息。即：

Signature signature = Signature.getInstance("SHA1withRSA");
signature.initVerify(pubKey);
signature.update(message);
bool ok = signature.verify(signatureValue);

Answer 2

我认为问题在于你实际上没有给它一个消息来验证。

RSA签名首先对消息进行散列（即“SHA1withRSA”中的“SHA1”），然后对其执行trapdoor operation。除非您知道一些秘密信息（RSA私钥），否则这是一个在一个方向上很容易做而在另一个方向很难做的操作。

要验证，首先要反转数学变换（因为它在一个方向上很容易），然后将签名中嵌入的散列与刚刚计算的消息的散列进行比较。签名本身不包含消息;要验证签名，您需要签名和签名的邮件。

在API级别，Signature类似乎希望您使用此签名所针对的消息内容来调用update。如果没有这个，它可能是将哈希值与空字符串的哈希值进行比较，因此除非您最初签名的邮件也是空字符串，否则签名实际上是无效的。

Answer 3

你是对的，谢谢杰克。以下方法工作正常（即使使用.NET创建的密钥）！我希望这有助于其他人。

public static void main(String[] args) {
    try{
        String userID = "189711";
        String companyCode = "ILIKEPIZZA";
        String combine = userID + "." + companyCode;
        String mod = "q0AwozeUj0VVkoksDQSCTj3QEgODomq4sAr02xMyIrWldZrNHhWfZAIcWt2MuAY3X6S3ZVUfOFXOrVbltRrO3F9Z6R8/jJIMv7wjkeVBFC5gncwGR0C3aV9gmF6II19jTKfF1sxb26iMEMAlMEOSnAAceNaJH91zBoaW7ZIh+qk=";
        String exp = "AQAB";
        byte[] modulusBytes = Base64.decodeBase64(mod.getBytes("UTF-8"));
        byte[] exponentBytes = Base64.decodeBase64(exp.getBytes("UTF-8"));
        String sign = "3753e672cfb21e3c182ef2df51f19edeffb63432ed338a47251326ccc14aa63883e910a140cf313754ebc6425aad434e309307cc882da6cd4a4f9f40bd14a9823aca145e5ffc97cd63dbb5925c049282416bdfd7d74ddeef7055065210a841793fe315dff5a44af19c1522daafdc2f7e61ce5a2b42ebf79dfb086e6d210168dd";
        BigInteger modulus = new BigInteger(1, modulusBytes );               
        BigInteger exponent = new BigInteger(1, exponentBytes);
        RSAPublicKeySpec rsaPubKey = new RSAPublicKeySpec(modulus, exponent);
        KeyFactory fact = KeyFactory.getInstance("RSA");
        PublicKey pubKey = fact.generatePublic(rsaPubKey);
        Signature signature = Signature.getInstance("SHA1withRSA");
        byte[] sigBytes = hexStringToByteArray(sign);
        signature.initVerify(pubKey);
        signature.update(combine.getBytes("UTF-8"));
        System.out.println(signature.verify(sigBytes));
    }catch(Exception e){
        System.out.println("Error: " + e.toString());
    }
}

signature.verify（）始终返回False

3 个答案: