ASP.. NET Core 5 -解码AES-GCM-256 JWE

Question

我正在尝试解码加密令牌，但未成功。

我尝试了c#的AesGcm类，但它给了我一个关于TAG的错误:

计算的身份验证标记与输入的身份验证标记不匹配。

这是我尝试解码的方式:

string tag =  token.Split(".")[4];
byte[] tag_byte = Base64UrlEncoder.DecodeBytes(tag);
new AesGcm(secretKey_byte).Decrypt(iv_byte, ciphertext_byte, tag_byte, decryptedPayload);

然后我切换到BouncyCastle，我得到这个错误:

MAC大小:176无效

代码:

using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Security;
string ciphertext = token.Split(".")[3];          
byte[] ciphertext_byte = Encoding.UTF8.GetBytes(ciphertext);          
string cipherText_Encoded = System.Convert.ToBase64String(ciphertext_byte);
string secretKey_hash = Utils.ComputeSha256Hash(secretKey);
string iv = token.Split(".")[2];
byte[] iv_byte = Encoding.UTF8.GetBytes(iv);
string iv_Encoded = System.Convert.ToBase64String(iv_byte);
string tag = token.Split(".")[4];
byte[] tag_byte = Encoding.UTF8.GetBytes(tag);
string decryptedToken = Utils.DecryptWithGCM(cipherText_Encoded, secretKey_hash, iv_Encoded , tag_byte);

,

public static string ComputeSha256Hash(string rawData)
{
// Create a SHA256   
using (SHA256 sha256Hash = SHA256.Create())
{
// ComputeHash - returns byte array  
byte[] bytes = sha256Hash.ComputeHash(Encoding.UTF8.GetBytes(rawData));

// Convert byte array to a string   
StringBuilder builder = new StringBuilder();
for (int i = 0; i < bytes.Length; i++)
{
builder.Append(bytes[i].ToString("x2"));
}
return builder.ToString();
}
}
public static string DecryptWithGCM(string EncryptedString, string KeyString, string NonceString, byte[] tag)
{
byte[] key = Convert.FromBase64String(KeyString);
byte[] nonce = Convert.FromBase64String(NonceString);
byte[] ciphertext = Convert.FromBase64String(EncryptedString);
var plaintextBytes = new byte[ciphertext.Length];
var cipher = new GcmBlockCipher(new AesEngine());
var parameters = new AeadParameters(new KeyParameter(key), tag.Length * 8, nonce);
cipher.Init(false, parameters);
var bcCiphertext = ciphertext.Concat(tag).ToArray();
var offset = cipher.ProcessBytes(bcCiphertext, 0, bcCiphertext.Length, plaintextBytes, 0);
cipher.DoFinal(plaintextBytes, offset);
return Encoding.UTF8.GetString(plaintextBytes);
}

这是我的令牌和秘钥

<<p>键/strong>:(哈希前)

04ee52c7e54ba6452efe6769836b4aa510c6010804fd5668515b305e9b929808

标记:

eyJhbGciOiJkaXIiLCJlbmMiOiJBMjU2R0NNIiwiY3R5IjoiSldUIn0..q3vM69iWaVqnwAcs.bt64YI5c0ndwJrWuK5teMiL0gVu8ZpfPAeXNZNKsad_Hu0Hkx6oy8nu3SRZxbUhaOsQ-nPUCyaoR3tyqsPTRJm4yskk61h3iY2kmhftqWE27poCgkJurifZOUNccX1EtXOx-Qd9SbAmUbJYCWRx98tG4VYb_oztSCy5lusYmbt-M32_UYpMvFMTH8pT4Ux7JittzKC3HOtxiJlbUCGO0Zz9U6KPtIG_CWs0hjweafmigo30xD99YEEpaljULMFfFGCylrfCGeyjyR1RFjmNXGdJsO0kohraJ-DHY9K_JMNi0trlvksJAZghifi-zdHSZgurF06bi6AMJjMqw2t6V2RHn_pUz8wLVoOlvHKtHOfziyg_tsM_GVOaEz-nmu29-bboRewlP7Ihvv1YgG0cOnhpqyd3s_WI7J3CJTtnEYdRQp1F2S8z5pNwrArVy-FxmvGVY-xgdenisG0tRbg3EmGF6kdhFOlSjaVSiYA_ZnQBVftIvz7pvL5kptTxTjgEBgnfAZtM89MNpCFIZ4yTKGtwnmyY9tIfpqmgCPP9erHYWgg1Sn14VibRZO86G_c5LR6n9ZW92qB4KD3SlbJ9IaA27bipwDsYFBllhBIrlhaxTmlifQz4UuaJ_5oRCfDn9faDDv3MaFYyvquAMMhrau8yio_hEgggzUqbzykYrNd6U6rwhHcOfNdardkIc7u9HrPH7AiYsZpVMZ6H5yctvykbVwpMiDgjSpG-_ox776uNdsWIQCp9z5JFawr4nxXsibcrYRJDvwKNwQkYj3Vox-e3mBsjz9jxIc-Yon4BlzTi8U__mhUg.1YVfxEJlvIKdVQVKtHu5ew

Answer 1

好的，我已经放弃了内置的解密器和BouncyCastle，并选择尝试Jose-jwt nuget包。https://github.com/dvsekhvalnov/jose-jwt

它有效!

byte[] secretKey_byte = Utils.ComputeSha256Hash(secretKey);
JweToken decryptedToken = JWE.Decrypt(token, secretKey_byte);

那么简单。解密后的JWT将在decryptedToken下。明文