[英]How to encrypt in RSA?
I want to write my own RSA encrypter without libaries! 我要编写没有库的RSA加密器!
Code: 码:
import java.util.Random;
public class Main {
public static void main(String[] args) {
System.out.println(createPrime());
}
private static byte encrypt(byte message) {
double p = createPrime();
double q = createPrime();
double e = 2 ^ new Random().nextInt(100) % (p * q);
byte ciphered = Math.pow(message, e);
return ciphered;
}
private static double createPrime() {
double testPow;
do {
int test = new Random().nextInt(20);
int power = new Random().nextInt(20);
test += 1;
power +=1;
testPow = Math.pow(test, power);
System.out.println("Double Math.pow: " + testPow);
} while (!testPrime(testPow));
return testPow;
}
private static Boolean testPrime(Double test) {
int factor = 2;
int lastFactor = 1;
while (test > 1) {
if (test % factor == 0) {
lastFactor = factor;
test /= factor;
while (test % factor == 0) {
test /= factor;
}
}
factor++;
}
Boolean isPrime = false;
if (test == lastFactor) {
isPrime = true;
}
return isPrime;
}
}
This is what I have for encrypting. 这就是我要加密的内容。 I don't know what I should do to correct this, but I have pretty much done this by hand before trying this.
我不知道该怎么做才能更正此问题,但是在尝试之前,我已经做了很多手工工作。
So I know that the equation to encrypt is c = m^e (mod N) and decryption m = c^d (mod N) 所以我知道要加密的方程是c = m ^ e(mod N)和解密m = c ^ d(mod N)
where p, q are prime numbers - m is message - c is ciphered text - e is totient of N - N is p times q - totient of N is (p-1)(q-1) 其中p,q是质数-m是消息-c是密文-e是N的上位字母-N是p的乘以q-N的上位字母是(p-1)(q-1)
Any help is appreciated 任何帮助表示赞赏
The first thing to do is to have a look at the class java.math.BigInteger. 首先要做的是查看类java.math.BigInteger。 This class will help you a lot to implement "School-book" RSA.
该课程将为您实施“学校手册” RSA带来很大帮助。
You didn't ask a real question, but I see a couple of problems anyways 您没有问一个真正的问题,但是我仍然看到几个问题
double e = 2 ^ new Random().nextInt(100) % (p * q);
I don't know what this is supposed to do, but it's wrong. 我不知道该怎么办,但这是错误的。 Did you mean
Math.Pow()
rather than ^
? 您是说
Math.Pow()
而不是^
吗? In any case, usually you just use some small constant with very few set bits for e
to make encryption fast. 在任何情况下,通常都只使用一些很小的常数(带有很少的设置位)来使
e
更快地进行加密。 e=3
or e=65
would work fine. e=3
或e=65
可以正常工作。
You don't seem to be calculating the private key ( d
), or even storing the public key ( e
, p*q
) at all. 您似乎根本没有计算私钥(
d
),甚至根本没有存储公钥( e
, p*q
)。
When you start using large numbers, int
and double
(??) will not be able to hold them. 当您开始使用大数时,
int
和double
(??)将无法保留它们。 Use BigInteger
instead. 改用
BigInteger
。
do {
testPow = Math.pow(test, power);
} while (!testPrime(testPow));
If power > 1
, testPow will never be prime... 如果
power > 1
,则testPow将永远不是素数...
I have not looked at testPrime()
, but you should be able to write some quick unit tests to convince yourself whether or not it probably works. 我没有看过
testPrime()
,但是您应该能够编写一些快速的单元测试来说服自己是否可行。
Java has built-in encryption algorithms under the java.security
package. Java在
java.security
包下具有内置的加密算法。 Check this . 检查一下 。 So no need for external libraries.
因此,无需外部库。 I see no production need to implement it yourself.
我认为没有生产需要自己实施。 Only if it is homework (which you didn't tag)
仅当是家庭作业(您未标记)时
I'd suggest reading/copying an existing implementation for reference, such as BouncyCastle: http://www.docjar.com/html/api/org/bouncycastle/crypto/engines/RSACoreEngine.java.html 我建议阅读/复制现有的实现以供参考,例如BouncyCastle: http : //www.docjar.com/html/api/org/bouncycastle/crypto/engines/RSACoreEngine.java.html
By the way, if you want this to be at all secure, you should be using java.security.SecureRandom, not java.util.Random 顺便说一句,如果您希望此操作完全安全,则应该使用java.security.SecureRandom,而不是java.util.Random
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