node.js - 使用带 Node 的 ursa 加密和解密字符串会引发解码错误

Question

我正在尝试使用 ursa 库在我当前的 nodejs 项目中使用 RSA 制作加密和解密逻辑。我真的在任何地方都找不到这方面的帮助，所以我希望有人能提供帮助。

每当我运行这段代码时，我都会收到以下与填充相关的解码错误(仅当DECRYPTING时。Encrypting does not break 虽然我不确定它是否正确):

“错误:0407A079:rsa例程:RSA_padding_check_PKCS1_OAEP:oaep解码错误”

我尝试将填充更改为 ursa.RSA_PKCS1_PADDING 而不是使用默认的 ursa.RSA_PKCS1_OAEP_PADDING 但 id 没有帮助。我尝试用一​​个填充加密并用另一个填充解密，但它没有用。我相信我为缓冲区和加密/解密方法尝试了所有编码组合(二进制、utf8 和 base64)，但效果不佳。

这是我要运行的全部测试代码:

var ursa = require("ursa");

var privateKey = ursa.generatePrivateKey(2048, 65537);

//var pub = privateKey.toPublicPem('base64');
//var priv = privateKey.toPrivatePem('base64');

var clearText = "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua."

var encrypted = encrypt(clearText, 256);
var decrypted = decrypt(encrypted, 256);


function encrypt(text, keySizeBytes){
    var buffer = new Buffer(text);
    var maxBufferSize = keySizeBytes - 42;
    var bytesCopied = 0;
    var finalString = "";

    //loops through all data buffer encrypting piece by piece
    while(bytesCopied < buffer.length){
        //calculates next maximun length for temporary buffer and creates it
        var amountToCopy = Math.min(maxBufferSize, buffer.length - bytesCopied);
        var tempBuffer = new Buffer(amountToCopy);

        //copies next chunk of data to the temporary buffer
        var nextEnd = bytesCopied + amountToCopy;
        buffer.copy(tempBuffer, 0, bytesCopied, nextEnd);

        //encrypts current chunk and concatenates with encrypted parts
        finalString += privateKey.encrypt(tempBuffer);

        bytesCopied += amountToCopy;
    }

    return finalString;
}

function decrypt(text, keySizeBytes){
    var buffer = new Buffer(text);
    var maxBufferSize = keySizeBytes - 1;
    var bytesCopied = 0;
    var finalString = "";

    //loops through all data buffer encrypting piece by piece
    while(bytesCopied < buffer.length){
        //calculates next maximun length for temporary buffer and creates it
        var amountToCopy = Math.min(maxBufferSize, buffer.length - bytesCopied);
        var tempBuffer = new Buffer(amountToCopy);

        //copies next chunk of data to the temporary buffer
        var nextEnd = bytesCopied + amountToCopy;
        buffer.copy(tempBuffer, 0, bytesCopied, nextEnd);

        //drecrypts current chunk and concatenates with decrypted parts
        finalString += privateKey.decrypt(tempBuffer);

        bytesCopied += amountToCopy;
    }

    return finalString;
}

我可能在这里做了一些非常愚蠢的事情，但老实说，此时我找不到问题所在。谢谢 =)

Answer 1

其中一个问题是，如果您未指定编码，ursa 加密和解密方法会返回一个 Buffer，因此我的串联会产生奇怪的结果。此外，我意识到任何使用 N 字节 key 加密的字符串都将具有 N 字节。考虑到这些，我改进了代码，这是我对任何需要使用 ursa 加密和解密任何大小的字符串的人的最终建议。

var ursa = require("ursa");

var clearText = "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua."
var bigText = "";
for(var i = 0; i < 100; i++){
    bigText += i +" " + clearText + "\n"; 
}

var keySizeBits = 1024;
var keyPair = ursa.generatePrivateKey(keySizeBits, 65537);

var encrypted = encrypt(bigText, keySizeBits/8);
console.log(encrypted);

var decrypted = decrypt(encrypted, keySizeBits/8);
console.log(decrypted);

function encrypt(clearText, keySizeBytes){
    var buffer = new Buffer(clearText);
    var maxBufferSize = keySizeBytes - 42; //according to ursa documentation
    var bytesDecrypted = 0;
    var encryptedBuffersList = [];

    //loops through all data buffer encrypting piece by piece
    while(bytesDecrypted < buffer.length){
        //calculates next maximun length for temporary buffer and creates it
        var amountToCopy = Math.min(maxBufferSize, buffer.length - bytesDecrypted);
        var tempBuffer = new Buffer(amountToCopy);

        //copies next chunk of data to the temporary buffer
        buffer.copy(tempBuffer, 0, bytesDecrypted, bytesDecrypted + amountToCopy);

        //encrypts and stores current chunk
        var encryptedBuffer = keyPair.encrypt(tempBuffer);
        encryptedBuffersList.push(encryptedBuffer);

        bytesDecrypted += amountToCopy;
    }

    //concatenates all encrypted buffers and returns the corresponding String
    return Buffer.concat(encryptedBuffersList).toString('base64');
}

function decrypt(encryptedString, keySizeBytes){

    var encryptedBuffer = new Buffer(encryptedString, 'base64');
    var decryptedBuffers = [];

    //if the clear text was encrypted with a key of size N, the encrypted 
    //result is a string formed by the concatenation of strings of N bytes long, 
    //so we can find out how many substrings there are by diving the final result
    //size per N
    var totalBuffers = encryptedBuffer.length / keySizeBytes;

    //decrypts each buffer and stores result buffer in an array
    for(var i = 0 ; i < totalBuffers; i++){
        //copies next buffer chunk to be decrypted in a temp buffer
        var tempBuffer = new Buffer(keySizeBytes);
        encryptedBuffer.copy(tempBuffer, 0, i*keySizeBytes, (i+1)*keySizeBytes);
        //decrypts and stores current chunk
        var decryptedBuffer = keyPair.decrypt(tempBuffer);
        decryptedBuffers.push(decryptedBuffer);
    }

    //concatenates all decrypted buffers and returns the corresponding String
    return Buffer.concat(decryptedBuffers).toString();
}

还是谢谢!如果有人有任何改进的想法，我们非常欢迎。

谢谢!