RSA/ECB/PKCS1将C#解密错误字符串填充到PrivateKey

Question

我在私钥转换中遇到错误，无法解密。错误：系统。InvalidCastException：无法强制转换"Org"类型的对象。BouncyCastle。加密。AsymmetricCipherKeyPair"类型为"Org。BouncyCastle。加密。AsymmetricKeyParameter"。

当我将其转换为AsymmetricCipherKeyPair类型时，该类型在底线中不匹配。我在等你的帮助。

static void Main()
{
var plainData = "plain_text";
RSA publicKeyEncryptor = getRSAPublic(@"MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAlYB5JrwA9fMxZxTRhG0NnKRwJizMZGJNq/xFfFxaEmKp3O6vZgsZMlFTi2kSC++yR/KriGKuGgbIYrgomn7BueoooAw5KLVO9CKKtNyQgg28vdOBbnQqljA+KID0PouAD8MqpDk9opi41zeEQPOSkAUsq5sHMptG7h9cgj0mNr2c4ffNolHAhPsrZVtGYtswhtznDkG463VOKLAmDLDeY9bASUsQXFOY+Em93GHFjStgZSTIEBof6HbUqIQf2rGjuPYCQsB/94BFma58epGz12zUPwKFMuxg89wbLOCjyAkocgS9zDnwKr7DVv08GmCUVVqI6ySzbWpKhiqWQvz4hwIDAQAB");
var plainBytes = Encoding.ASCII.GetBytes(plainData);
string encryptedPayload = System.Convert.ToBase64String(publicKeyEncryptor.Encrypt(plainBytes, RSAEncryptionPadding.Pkcs1));

RSA privateKeyDecyrpt = getRSAPrivate();
var y = privateKeyDecyrpt.Decrypt(Encoding.ASCII.GetBytes(encryptedPayload), RSAEncryptionPadding.Pkcs1);
Console.WriteLine(encryptedPayload);
}
public static RSA getRSAPublic(string publicKey)
{
string publicKeyPem = $"-----BEGIN PUBLIC KEY-----rn{ publicKey }rn-----END PUBLIC KEY-----rn";
var pemReader = new PemReader(new StringReader(publicKeyPem));
AsymmetricKeyParameter keyPairRaw = (AsymmetricKeyParameter)pemReader.ReadObject();
RSAParameters rsaParams = DotNetUtilities.ToRSAParameters((RsaKeyParameters)keyPairRaw);
RSA rsaObj = System.Security.Cryptography.RSA.Create();
rsaObj.ImportParameters(rsaParams);
return rsaObj;
}
public static RSA getRSAPrivate()
{
string privateKeyPem = @"-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----";
var pemReader = new PemReader(new StringReader(privateKeyPem));
AsymmetricKeyParameter keyPairRaw = (AsymmetricKeyParameter)pemReader.ReadObject();
RSAParameters rsaParams = DotNetUtilities.ToRSAParameters((RsaKeyParameters)keyPairRaw);
RSA rsaObj = System.Security.Cryptography.RSA.Create();
rsaObj.ImportParameters(rsaParams);
return rsaObj;
}

Answer 1

代码本质上包含与转换相关的错误，这些错误在调试过程中最容易通过确定对象类型来识别：

我在私钥转换中遇到错误，无法解密。错误：系统。InvalidCastException：无法强制转换"Org"类型的对象。BouncyCastle。加密。AsymmetricCipherKeyPair"类型为"Org。BouncyCastle。加密。AsymmetricKeyParameter"。

不能像公钥那样1:1导入私钥，因为两者的格式不同。在私钥的情况下，PemReader返回不同的对象类型，即AsymmetricCipherKeyPair，不能将其强制转换为AsymmetricKeyParameter。这就是错误消息所说的内容。所以它一定是：

AsymmetricCipherKeyPair keyPairRaw = (AsymmetricCipherKeyPair)pemReader.ReadObject();

当我将其转换为AsymmetricCipherKeyPair类型时，该类型在底线中不匹配。

您还需要修改此行。在这里，您必须传递一个必须转换为RsaPrivateCrtKeyParameters:的keyPairRaw.Private

RSAParameters rsaParams = DotNetUtilities.ToRSAParameters((RsaPrivateCrtKeyParameters)keyPairRaw.Private);

通过这些更改，私钥的导入工作正常。

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另一个错误在解密中。密文在加密过程中是Base64编码的，因此在解密过程中必须是Base64解码的，而不是ASCII编码的，即正确的是：

var decrypted = privateKeyDecyrpt.Decrypt(Convert.FromBase64String(encryptedPayload), RSAEncryptionPadding.Pkcs1);

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请记住，在中导入密钥的选项。NET高度依赖于版本。有些版本可以开箱即用地导入PEM密钥(例如，从.NET 5开始(，因此不需要BouncyCastle。