使用RSA-OAEP解密用JavaScript加密的C＃中的数据时，OAEP填充错误

Question

在我不深入讨论细节之前，我要完成的高级工作是使用JavaScript加密一些数据，将其发送到Web服务器，然后使用C＃解密该加密的数据。 我遇到的问题是解密C＃中的数据。

我正在像这样用JavaScript加密一些数据（我删除了多余的代码）：

// https://github.com/diafygi/webcrypto-examples#rsa-oaep---encrypt
window.crypto.subtle.encrypt(
    {
        name: "RSA-OAEP"
    },
    publicKey,
    data
)
.then(function (encrypted) {
    // ...
});

我确认可以像这样用JavaScript对其进行解密（请注意，我实际上并不想这样做，但是我这样做是为了证明可以解密数据）：

function decryptValue () {

    // Base64 decode the encrypted data for the value "Bob".
    var data = base64Decode("CthOUMzRdtSwo+4twgtjCA674G3UosWypUZv5E7uxG7GqYPiIJ+E+Uq7vbElp/bahB1fJrgq1qbdMrUZnSypVqBwYnccSxwablO15OOXl9Rn1e7w9V9fuMxtUqvhn+YZezk1623Qd7f5XTYjf6POwixtrgfZtdA+qh00ktKiVBpQKNG/bxhV94fK9+hb+qnzPmXilr9QF5rSQTd4hYHmYcR2ljVCDDZMV3tCVUTecWjS5HbOA1254ve/q3ulBLoPQTE58g7FwDQUZnd7XBdRSwYnrBWTJh8nmJ0PDfn+mCTGEI86S7HtoFYsE+Hezd24Z523phGEVrdMC9Ob1LlXEA==");

    // Get private key.
    var keyPromise = importPrivateKey();
    return keyPromise.then(function (privateKey) {

        // Decrypt the value.
        return window.crypto.subtle.decrypt(
            {
                name: "RSA-OAEP"
            },
            privateKey,
            data
        )
        .then(function (decrypted) {

            // Log the decrypted value to the console.
            console.log(arrayBufferToString(decrypted));

        });

    });

}

为简单起见，该代码示例正在解密先前加密的“ Bob”值。 这很好。

当我尝试解密C＃中的值时，会发生问题：

public static string Decrypt()
{

    // The encrypted and base64 encoded value for "Bob".
    var encryptedValue = "CthOUMzRdtSwo+4twgtjCA674G3UosWypUZv5E7uxG7GqYPiIJ+E+Uq7vbElp/bahB1fJrgq1qbdMrUZnSypVqBwYnccSxwablO15OOXl9Rn1e7w9V9fuMxtUqvhn+YZezk1623Qd7f5XTYjf6POwixtrgfZtdA+qh00ktKiVBpQKNG/bxhV94fK9+hb+qnzPmXilr9QF5rSQTd4hYHmYcR2ljVCDDZMV3tCVUTecWjS5HbOA1254ve/q3ulBLoPQTE58g7FwDQUZnd7XBdRSwYnrBWTJh8nmJ0PDfn+mCTGEI86S7HtoFYsE+Hezd24Z523phGEVrdMC9Ob1LlXEA==";

    // Assuming RSA-OAEP.
    var doOaep = true;

    // Setup encryption algorithm.
    var provider = GetPrivateKey();

    // Decrypt value.
    var encryptedData = Convert.FromBase64String(encryptedValue);
    // This line throws an error: "Error occurred while decoding OAEP padding."
    var decryptedData = provider.Decrypt(encryptedData, doOaep);
    var decryptedText = Encoding.Unicode.GetString(decryptedData);

    // Return decrypted text.
    return decryptedText;

}

该行显示provider.Decrypt(encryptedData, doOaep)会引发错误，并显示一条消息“解码OAEP填充时发生错误”。 堆栈跟踪为：

Error occurred while decoding OAEP padding.
    at System.Security.Cryptography.RSACryptoServiceProvider.DecryptKey(SafeKeyHandle pKeyContext, Byte[] pbEncryptedKey, Int32 cbEncryptedKey, Boolean fOAEP, ObjectHandleOnStack ohRetDecryptedKey)
    at System.Security.Cryptography.RSACryptoServiceProvider.Decrypt(Byte[] rgb, Boolean fOAEP)

似乎JavaScript加密值的方式与C＃加密值的方式不兼容。 在我完全放弃这种方法并尝试使用另一个JavaScript库进行加密之前，是否有解决此错误的方法？

对于其他上下文，我猜测此错误与本文中提到的内容有关： https : //www.codeproject.com/Articles/11479/RSA-Interoperability-between-JavaScript-and-RSACry

它说：

JavaScript代码中不兼容的填充方案将在服务器端产生“错误数据”异常。

因此，JavaScript代码需要实现.NET RSA实现中使用的两种填充方案中的一种，第一种是PKCS＃1 v1.5填充，另一种是OAEP（PKCS＃1 v2）填充。

我没有得到确切的例外，但是也许自从写这篇文章以来，错误消息已经改变了。 无论如何，该文章所说的内容似乎暗示着JavaScript的加密方式与C＃的解密方式不兼容（即，由于C＃对填充的要求）。

有什么我想念的吗？ 是否有一些参数或一些简单的方法来使加密在JavaScript中起作用，而解密在C＃中起作用？ 也许有一些C＃库以与JavaScript加密方式兼容的方式解密？

这是一个完整的示例，显示JavaScript正在正确解密（仅适用于某些浏览器...可能无法在IE上运行）：

 function decryptValue () { // Base64 decode the encrypted data for the value "Bob". var data = base64Decode("CthOUMzRdtSwo+4twgtjCA674G3UosWypUZv5E7uxG7GqYPiIJ+E+Uq7vbElp/bahB1fJrgq1qbdMrUZnSypVqBwYnccSxwablO15OOXl9Rn1e7w9V9fuMxtUqvhn+YZezk1623Qd7f5XTYjf6POwixtrgfZtdA+qh00ktKiVBpQKNG/bxhV94fK9+hb+qnzPmXilr9QF5rSQTd4hYHmYcR2ljVCDDZMV3tCVUTecWjS5HbOA1254ve/q3ulBLoPQTE58g7FwDQUZnd7XBdRSwYnrBWTJh8nmJ0PDfn+mCTGEI86S7HtoFYsE+Hezd24Z523phGEVrdMC9Ob1LlXEA=="); // Get private key. var keyPromise = importPrivateKey(); return keyPromise.then(function (privateKey) { // Decrypt the value. return window.crypto.subtle.decrypt( { name: "RSA-OAEP" }, privateKey, data ) .then(function (decrypted) { // Log the decrypted value to the console. console.log("Decrypted value: " + arrayBufferToString(decrypted)); }); }); } function importPrivateKey() { var rawKey = { "alg": "RSA-OAEP-256", "d": "E4KDwgxy7jFrqeXqKjxPTGOdbEoZ2aWj5qcZhUJcnr9Qh_jg_grkgpHVwEbQifTxsipXTiR3_ygspI4XFoeV-wDVfWqWCVR3_bHChF9PW8Ak1x_dBSS28BMs8PdthI1pDbpqPhmMcF4riHCtNo1M1v8cLdeaiqiXitNVBkaTePsDiucfwOy1rgxwBqAL1CNJhP8oRiYkxD-gfE_EapWuXY9-wF9O-lXPLSTKWgMmmVxSmhUP-Uqk7cJ24UH9C7W7hnSQU4pkfD5XHx3_2WO2GMKKZcqz39wJUrQzrIO7539SYsQ3rEe4aMJyL4U-Ib4_purzVS0DRjzGxK8chT2guQ", "dp": "kibhWHk1R6yBlhZbjIrNl9beAkyV5vtFsj_F0ixbIITzjSqI_td71sWjKQvJ2rR7hu5DYTZ4p3XwBeQ2jpYQV-y5uh4v7rGngh-0GHuHqMiUQnejgYGcHgng4iCM4e3aTO7QUlP8jqRfxw6xpfNTjrVbAL8LtdCG21vmqOiLkXE", "dq": "qLF9x-zKfaXlLsNgBQ1ZnaQexrnJRqrRh9JSU85fCNy5mmpKWAUbCHB-59CGAId8wMAnAyEpjcBOKNTqWSlNzp84xeUHcyPI-Dt4Yp_Y_dXjGAYntALSJs4qeF2rk55MSpiSD_KSU4DknX_E_G2rFMY7AZOSwi1D8YcNmj5okTE", "e": "AQAB", "ext": true, "key_ops": [ "decrypt" ], "kty": "RSA", "n": "oQeTwOlTc6rIb2kddwIOc0Ywslc7YzJSRZd_PegW7T3nO3DqCI5kp5EJmnGP8JJ9sbyVYyAHFLZQtMP69UspZFn__fBk2LTp2QdqBSMHbObENcSiG2FH-pZSwCaj3Pvy-qvTjnkxxN-3OE6oB8EcX5ekZwCZzAxazbVXctY_hCcaTWG7ugwc_ZyvhsdE7wa3pnTfXYHWXcDDT8FTpYl62aqWsEIUAJSkgmQ9zce0RiDUjBJyJEM9P0ihp1Ab8BD88pEM22-PXfiOesRzp5yOsjzI3kdr5KPsshstneJEGHYae5GZXLUpnVMRY1TCFFLbkPwK6oVkRaVU1RvK9ssO3Q", "p": "2TTEToB4AuPIPPpg3yTyBlGb_m-f4r-TxpU96ConV2p696_4QI6jlPWwgcC9Vdma_Da43AGuyLzIptgkzF8nSjV80VwwDKQ1YkFPc6ZqB2isvExuieSP6_jLlB-fCyCLqtTxpPm2VcK16Pqm0s5T0QGH6cQjjm1r2Ww1wuaiQbk", "q": "vcpFwkZKZ3hx3FpHgy3ScuuTRSPO2ge8TE8UMJdCrEnpftAeYuVYrJqnxfzKgyl02OijAUi1eozJxj_lM5McxrKZEEAvo6e8wtzl2hnkUh-KWoBJ8ii0VJcu6U5vs4pcv-lYBPFC6fzoGnUw8LNWMxb5ejgYbLUWp10BbfkWGEU", "qi": "Mza7JYleki7BvmD3dX5CO2nkD3mBGz4_0P_aoWyHEkWu4p5XWillaRVWyLnQEubLvAduUCr-lhfNmzdUhHecpE438_LQNtKRyOq9zkvjsMOGDmbkKpZ7-aTSshax6KNlYOWdOkadjuLtRExCmwbzu5lgI4NwacxSs5MfjHMrTCo" }; return window.crypto.subtle.importKey( "jwk", rawKey, { name: "RSA-OAEP", hash: { name: "SHA-256" } }, true, ["decrypt"] ); } function arrayBufferToString(buffer) { var result = ''; var bytes = new Uint8Array(buffer); for (var i = 0; i < bytes.length; i++) { result += String.fromCharCode(bytes[i]); } return result; } // Decodes a base64 encoded string into an ArrayBuffer. // https://stackoverflow.com/a/36378903/2052963 function base64Decode(base64) { var binary_string = window.atob(base64); return stringToArrayBuffer(binary_string); } // Converts a string to an ArrayBuffer. function stringToArrayBuffer(value) { var bytes = new Uint8Array(value.length); for (var i = 0; i < value.length; i++) { bytes[i] = value.charCodeAt(i); } return bytes.buffer; } decryptValue(); 

顺便说一句，我的一些代码示例显示了我正在使用的私钥。 这是为了帮助您理解代码（这是一个扔掉的钥匙）。 实际上，这就是我在C＃中获取私钥的方法：

private static RSACryptoServiceProvider GetPrivateKey()
{
    RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
    RSAParameters RSAparams = new RSAParameters();
    RSAparams.Modulus = Base64UrlDecode("oQeTwOlTc6rIb2kddwIOc0Ywslc7YzJSRZd_PegW7T3nO3DqCI5kp5EJmnGP8JJ9sbyVYyAHFLZQtMP69UspZFn__fBk2LTp2QdqBSMHbObENcSiG2FH-pZSwCaj3Pvy-qvTjnkxxN-3OE6oB8EcX5ekZwCZzAxazbVXctY_hCcaTWG7ugwc_ZyvhsdE7wa3pnTfXYHWXcDDT8FTpYl62aqWsEIUAJSkgmQ9zce0RiDUjBJyJEM9P0ihp1Ab8BD88pEM22-PXfiOesRzp5yOsjzI3kdr5KPsshstneJEGHYae5GZXLUpnVMRY1TCFFLbkPwK6oVkRaVU1RvK9ssO3Q");
    RSAparams.Exponent = Base64UrlDecode("AQAB");
    RSAparams.D = Base64UrlDecode("E4KDwgxy7jFrqeXqKjxPTGOdbEoZ2aWj5qcZhUJcnr9Qh_jg_grkgpHVwEbQifTxsipXTiR3_ygspI4XFoeV-wDVfWqWCVR3_bHChF9PW8Ak1x_dBSS28BMs8PdthI1pDbpqPhmMcF4riHCtNo1M1v8cLdeaiqiXitNVBkaTePsDiucfwOy1rgxwBqAL1CNJhP8oRiYkxD-gfE_EapWuXY9-wF9O-lXPLSTKWgMmmVxSmhUP-Uqk7cJ24UH9C7W7hnSQU4pkfD5XHx3_2WO2GMKKZcqz39wJUrQzrIO7539SYsQ3rEe4aMJyL4U-Ib4_purzVS0DRjzGxK8chT2guQ");
    RSAparams.P = Base64UrlDecode("2TTEToB4AuPIPPpg3yTyBlGb_m-f4r-TxpU96ConV2p696_4QI6jlPWwgcC9Vdma_Da43AGuyLzIptgkzF8nSjV80VwwDKQ1YkFPc6ZqB2isvExuieSP6_jLlB-fCyCLqtTxpPm2VcK16Pqm0s5T0QGH6cQjjm1r2Ww1wuaiQbk");
    RSAparams.Q = Base64UrlDecode("vcpFwkZKZ3hx3FpHgy3ScuuTRSPO2ge8TE8UMJdCrEnpftAeYuVYrJqnxfzKgyl02OijAUi1eozJxj_lM5McxrKZEEAvo6e8wtzl2hnkUh-KWoBJ8ii0VJcu6U5vs4pcv-lYBPFC6fzoGnUw8LNWMxb5ejgYbLUWp10BbfkWGEU");
    RSAparams.DP = Base64UrlDecode("kibhWHk1R6yBlhZbjIrNl9beAkyV5vtFsj_F0ixbIITzjSqI_td71sWjKQvJ2rR7hu5DYTZ4p3XwBeQ2jpYQV-y5uh4v7rGngh-0GHuHqMiUQnejgYGcHgng4iCM4e3aTO7QUlP8jqRfxw6xpfNTjrVbAL8LtdCG21vmqOiLkXE");
    RSAparams.DQ = Base64UrlDecode("qLF9x-zKfaXlLsNgBQ1ZnaQexrnJRqrRh9JSU85fCNy5mmpKWAUbCHB-59CGAId8wMAnAyEpjcBOKNTqWSlNzp84xeUHcyPI-Dt4Yp_Y_dXjGAYntALSJs4qeF2rk55MSpiSD_KSU4DknX_E_G2rFMY7AZOSwi1D8YcNmj5okTE");
    RSAparams.InverseQ = Base64UrlDecode("Mza7JYleki7BvmD3dX5CO2nkD3mBGz4_0P_aoWyHEkWu4p5XWillaRVWyLnQEubLvAduUCr-lhfNmzdUhHecpE438_LQNtKRyOq9zkvjsMOGDmbkKpZ7-aTSshax6KNlYOWdOkadjuLtRExCmwbzu5lgI4NwacxSs5MfjHMrTCo");
    RSA.ImportParameters(RSAparams);
    return RSA;
}

// From the PDF here: https://www.rfc-editor.org/info/rfc7515
// Also see: https://auth0.com/docs/jwks
public static byte[] Base64UrlDecode(string arg)
{
    string s = arg;
    s = s.Replace('-', '+'); // 62nd char of encoding
    s = s.Replace('_', '/'); // 63rd char of encoding
    switch (s.Length % 4) // Pad with trailing '='s
    {
        case 0: break; // No pad chars in this case
        case 2: s += "=="; break; // Two pad chars
        case 3: s += "="; break; // One pad char
        default:
            throw new System.Exception(
        "Illegal base64url string!");
    }
    return Convert.FromBase64String(s); // Standard base64 decoder
}

Answer 1

由于您将OAEP与SHA-2-256结合使用，因此需要从RSACryptoServiceProvider迁移到RSACng（.NET 4.6+）。 请注意，除了ctor调用之外，我还消除了有关使用哪种实现的知识。

private static RSA GetPrivateKey()
{
    // build the RSAParams as before, then
    RSA rsa = new RSACng();
    rsa.ImportParameters(RSAparams);
    return rsa;
}

// Setup encryption algorithm.
var provider = GetPrivateKey();
...
var decryptedData = provider.Decrypt(encryptedData, RSAEncryptionPadding.OaepSHA256);

Answer 2

我无法测试@bartonjs的答案，因为我无法访问Windows计算机，并且Mono显然未实现RSACng。 以下是使用Bouncycastle C＃库解密密文的示例。 注意， OaepPadding(... ）对Oaep哈希和MGF哈希都使用SHA-256。 显然，这是与您的javascript代码进行互操作所需要的。 另外，请注意，我使用了Encoding.UTF8.GetString()而您使用了Encoding.Unicode.GetString() 。 编码绝对不是UTF-16，这是Encoding.Unicode给您的。

using System;
using System.Text;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Digests;
using Org.BouncyCastle.Crypto.Encodings;
using Org.BouncyCastle.Crypto.Engines;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Math;

namespace RsaSha256OaepDecrypt
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            var encryptedValue = "CthOUMzRdtSwo+4twgtjCA674G3UosWypUZv5E7uxG7GqYPiIJ+E+Uq7vbElp/bahB1fJrgq1qbdMrUZnSypVqBwYnccSxwablO15OOXl9Rn1e7w9V9fuMxtUqvhn+YZezk1623Qd7f5XTYjf6POwixtrgfZtdA+qh00ktKiVBpQKNG/bxhV94fK9+hb+qnzPmXilr9QF5rSQTd4hYHmYcR2ljVCDDZMV3tCVUTecWjS5HbOA1254ve/q3ulBLoPQTE58g7FwDQUZnd7XBdRSwYnrBWTJh8nmJ0PDfn+mCTGEI86S7HtoFYsE+Hezd24Z523phGEVrdMC9Ob1LlXEA==";
            var encryptedData = Convert.FromBase64String(encryptedValue);
            var rsaPrivate = GetPrivateKey();
            IAsymmetricBlockCipher cipher0 = new RsaBlindedEngine();
            cipher0 = new OaepEncoding(cipher0, new Sha256Digest(), new Sha256Digest(), null);
            BufferedAsymmetricBlockCipher cipher = new BufferedAsymmetricBlockCipher(cipher0);
            cipher.Init(false, rsaPrivate);
            cipher.ProcessBytes(encryptedData, 0, encryptedData.Length);
            var decryptedData = cipher.DoFinal();
            var decryptedText = Encoding.UTF8.GetString(decryptedData);
            Console.WriteLine(decryptedText);
        }

        private static BigInteger makeBigInt(String b64Url)
        {
            var bytes = Base64UrlDecode(b64Url);
            if ((sbyte)bytes[0] < 0)
            {
                // prepend a zero byte to make it positive.
                var bytes1 = new byte[bytes.Length + 1];
                bytes1[0] = 0;
                bytes.CopyTo(bytes1, 1);
                bytes = bytes1;
            }

            return new BigInteger(bytes);
        }
        private static AsymmetricKeyParameter GetPrivateKey()
        {
            //RSAParameters RSAparams = new RSAParameters();
            var Modulus = makeBigInt("oQeTwOlTc6rIb2kddwIOc0Ywslc7YzJSRZd_PegW7T3nO3DqCI5kp5EJmnGP8JJ9sbyVYyAHFLZQtMP69UspZFn__fBk2LTp2QdqBSMHbObENcSiG2FH-pZSwCaj3Pvy-qvTjnkxxN-3OE6oB8EcX5ekZwCZzAxazbVXctY_hCcaTWG7ugwc_ZyvhsdE7wa3pnTfXYHWXcDDT8FTpYl62aqWsEIUAJSkgmQ9zce0RiDUjBJyJEM9P0ihp1Ab8BD88pEM22-PXfiOesRzp5yOsjzI3kdr5KPsshstneJEGHYae5GZXLUpnVMRY1TCFFLbkPwK6oVkRaVU1RvK9ssO3Q");
            var Exponent = makeBigInt("AQAB");
            var D = makeBigInt("E4KDwgxy7jFrqeXqKjxPTGOdbEoZ2aWj5qcZhUJcnr9Qh_jg_grkgpHVwEbQifTxsipXTiR3_ygspI4XFoeV-wDVfWqWCVR3_bHChF9PW8Ak1x_dBSS28BMs8PdthI1pDbpqPhmMcF4riHCtNo1M1v8cLdeaiqiXitNVBkaTePsDiucfwOy1rgxwBqAL1CNJhP8oRiYkxD-gfE_EapWuXY9-wF9O-lXPLSTKWgMmmVxSmhUP-Uqk7cJ24UH9C7W7hnSQU4pkfD5XHx3_2WO2GMKKZcqz39wJUrQzrIO7539SYsQ3rEe4aMJyL4U-Ib4_purzVS0DRjzGxK8chT2guQ");
            var P = makeBigInt("2TTEToB4AuPIPPpg3yTyBlGb_m-f4r-TxpU96ConV2p696_4QI6jlPWwgcC9Vdma_Da43AGuyLzIptgkzF8nSjV80VwwDKQ1YkFPc6ZqB2isvExuieSP6_jLlB-fCyCLqtTxpPm2VcK16Pqm0s5T0QGH6cQjjm1r2Ww1wuaiQbk");
            var Q = makeBigInt("vcpFwkZKZ3hx3FpHgy3ScuuTRSPO2ge8TE8UMJdCrEnpftAeYuVYrJqnxfzKgyl02OijAUi1eozJxj_lM5McxrKZEEAvo6e8wtzl2hnkUh-KWoBJ8ii0VJcu6U5vs4pcv-lYBPFC6fzoGnUw8LNWMxb5ejgYbLUWp10BbfkWGEU");
            var DP = makeBigInt("kibhWHk1R6yBlhZbjIrNl9beAkyV5vtFsj_F0ixbIITzjSqI_td71sWjKQvJ2rR7hu5DYTZ4p3XwBeQ2jpYQV-y5uh4v7rGngh-0GHuHqMiUQnejgYGcHgng4iCM4e3aTO7QUlP8jqRfxw6xpfNTjrVbAL8LtdCG21vmqOiLkXE");
            var DQ = makeBigInt("qLF9x-zKfaXlLsNgBQ1ZnaQexrnJRqrRh9JSU85fCNy5mmpKWAUbCHB-59CGAId8wMAnAyEpjcBOKNTqWSlNzp84xeUHcyPI-Dt4Yp_Y_dXjGAYntALSJs4qeF2rk55MSpiSD_KSU4DknX_E_G2rFMY7AZOSwi1D8YcNmj5okTE");
            var InverseQ = makeBigInt("Mza7JYleki7BvmD3dX5CO2nkD3mBGz4_0P_aoWyHEkWu4p5XWillaRVWyLnQEubLvAduUCr-lhfNmzdUhHecpE438_LQNtKRyOq9zkvjsMOGDmbkKpZ7-aTSshax6KNlYOWdOkadjuLtRExCmwbzu5lgI4NwacxSs5MfjHMrTCo");
            var rsa = new RsaPrivateCrtKeyParameters(Modulus, Exponent, D, P, Q, DP, DQ, InverseQ);
            return rsa;
        }

        // From the PDF here: https://www.rfc-editor.org/info/rfc7515
        // Also see: https://auth0.com/docs/jwks

        public static byte[] Base64UrlDecode(string arg)
        {
            string s = arg;
            s = s.Replace('-', '+'); // 62nd char of encoding
            s = s.Replace('_', '/'); // 63rd char of encoding
            switch (s.Length % 4) // Pad with trailing '='s
            {
                case 0: break; // No pad chars in this case
                case 2: s += "=="; break; // Two pad chars
                case 3: s += "="; break; // One pad char
                default:
                    throw new System.Exception(
                "Illegal base64url string!");
            }
            return Convert.FromBase64String(s); // Standard base64 decoder
        }
    }
}