无法使用 .pem 解密字符串答案

【问题标题】：Fail to decrypt string using .pem无法使用 .pem 解密字符串
【发布时间】：2016-03-18 04:12:39
【问题描述】：

我想将解密后的字符串转换为数据字符串（我可以读取属性）

我尝试了here的代码

string token ="eyJhbGciOiJSUzI1NiJ9.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.CfcVsKidaHi6QEneYDfox9509SnIQUQZS6OUWf3jBN4OnTEQ-xFeHeIuQP6qgEK3b_0fLjWZ4OT7qnItLMKYg0vd68OxjDbHw79C4jQNnxq1EUgsEs72-gNNBV42n6I0R5VZy4t6AuKgHTFp6gN4fTisfA7vnX2Vq5Sg2faAoMl2nevN7F1P9YEWFPea9qoDqmPwGY72DvEauZNZmIb7OvtRvoBFAK_cIJvuRShIzUfQ5q4W4sMiRH92Ou_6S7k4NfqO8kOdoJkSqZCDlhJIdAmyW4IBsYc5TvgeoGIrzgKCVr2_1wM0RHXE3vq6oobe2rB68Rc8eQ0VYzH6fH4KQA";
var bytesToDecrypt = Convert.FromBase64String(token); // string to decrypt, base64 encoded

AsymmetricCipherKeyPair keyPair; 

using (var reader = File.OpenText(@"c:\myprivatekey.pem")) // file containing RSA PKCS1 private key
    keyPair = (AsymmetricCipherKeyPair) new PemReader(reader).ReadObject(); 

var decryptEngine = new Pkcs1Encoding(new RsaEngine());
decryptEngine.Init(false, keyPair.Private); 

var decrypted = Encoding.UTF8.GetString(decryptEngine.ProcessBlock(bytesToDecrypt, 0, bytesToDecrypt.Length));

但是，它在第 2 行抛出异常：

var bytesToDecrypt = Convert.FromBase64String(token); //exception

例外是：

The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.

如何解决？

【问题讨论】：

标签： c# encryption pem

【解决方案1】：

我对您的代码进行了一些尝试，这对我有用：

        string token = "eyJhbGciOiJSUzI1NiJ9.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.CfcVsKidaHi6QEneYDfox9509SnIQUQZS6OUWf3jBN4OnTEQ-xFeHeIuQP6qgEK3b_0fLjWZ4OT7qnItLMKYg0vd68OxjDbHw79C4jQNnxq1EUgsEs72-gNNBV42n6I0R5VZy4t6AuKgHTFp6gN4fTisfA7vnX2Vq5Sg2faAoMl2nevN7F1P9YEWFPea9qoDqmPwGY72DvEauZNZmIb7OvtRvoBFAK_cIJvuRShIzUfQ5q4W4sMiRH92Ou_6S7k4NfqO8kOdoJkSqZCDlhJIdAmyW4IBsYc5TvgeoGIrzgKCVr2_1wM0RHXE3vq6oobe2rB68Rc8eQ0VYzH6fH4KQA";
        string converted = token.Replace("-", "");
        converted = converted.Replace("_", "");
        converted = converted.Replace(".", "");
        int mod4 = converted.Length % 4;
        if (mod4 > 0)
        {
            converted += new string('=', 4 - mod4);
        }
        var bytesToDecrypt = Convert.FromBase64String(converted);

您遇到异常可能是因为有一些字符（如（-、_、.）在 base 64 字符串中无效，另一个是您的字符串长度应该具有正确的长度还。有关更多信息，您可以看到这个- Wikipedia 和 MSDN

【讨论】：