C#：解码 OAEP 填充奇怪问题时出错
C#: Error while decoding OAEP padding weird issue
我目前正在研究 class，它使用随机生成的加密密钥加密大量文本，该加密密钥由来自智能卡的 X509 证书加密，使用 RSACryptoServiceProvider 执行主密钥加密和解密操作。但是，当我将 fOEAP 填充选项设置为 true 时，每次解密时都会出现 "Error while decoding OAEP padding" 错误。我检查了密钥大小，它在可接受的范围内。我已经通过断点来确保从加密函数返回的 Base64 字符串与再次加载文件时传递回解密函数的加密 Base64 字符串完全相同。
密钥对绝对正确，因为没有 OAEP 也能正常工作。我也检查了文本编码。
编辑：事实证明这可能是智能卡特定问题，当我尝试使用本地 X509 证书解密时解密成功。
编辑：这是失败的解密代码：
string TestString = "Hello World!";
X509Certificate2 cert = DRXEncrypter.GetCertificate("Select a test certificate", "Select a certificate to use for this test from the local store.");
string key = DRXEncrypter.GenerateEncryptionKey(214);
Console.WriteLine("Encryption Key: " + key);
string encrypted = DRXEncrypter.EncryptBody(TestString, key);
Console.WriteLine("Encrypted Body: " + encrypted);
string cryptokey = DRXEncrypter.EncryptWithCert(cert, key);
Console.WriteLine("Encrypted Decryption Key: " + cryptokey);
string decrypted = DRXEncrypter.DecryptBody(encrypted, cryptokey, cert);
Console.WriteLine("Decrypted Body: " + decrypted);
Console.WriteLine("Output String: " + decrypted + ".");
这是我编写的来自加密提供商 class 的代码。我已经在这个问题上停留了几个小时，所以如果有人能帮助我就太好了。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.IO;
namespace CoreDRXEditor
{
public class DRXEncrypter
{
private byte[] Salt = Encoding.ASCII.GetBytes("81PO9j8I1a94j");
private string EncryptionKey;
private const bool UseOAEP = true;
public DRXEncrypter(string EncryptionKey)
{
this.EncryptionKey = EncryptionKey;
}
public static string EncryptBody(string body, string encryptionkey)
{
// Use the plaintext master key to encrypt the body.
DRXEncrypter enc = new DRXEncrypter(encryptionkey);
// Encrypt the body.
return enc.Encrypt(body);
}
public static int GetMaxKeySize(X509Certificate2 cert)
{
RSACryptoServiceProvider csp = cert.PublicKey.Key as RSACryptoServiceProvider;
return csp.KeySize;
}
public static string DecryptBody(string body, string encryptionkey, X509Certificate2 cert)
{
// Decrypt the encrypted encryption key with the certificate.
string DecryptedKey = Convert.ToBase64String(DecryptWithCert(cert, encryptionkey));
// Create a new DRXEncrypter using the decrypted encryption key to decrypt the body.
DRXEncrypter enc = new DRXEncrypter(DecryptedKey);
// Return the decrypted body.
return enc.Decrypt(body);
}
public static string GenerateEncryptionKey(int KeyLength)
{
using (RandomNumberGenerator rng = new RNGCryptoServiceProvider())
{
byte[] CryptoBytes = new byte[KeyLength];
rng.GetBytes(CryptoBytes);
return Convert.ToBase64String(CryptoBytes);
}
}
public static X509Certificate2 GetCertificate(string title, string message)
{
X509Store cstore = new X509Store(StoreLocation.CurrentUser);
cstore.Open(OpenFlags.ReadOnly);
X509CertificateCollection certs = X509Certificate2UI.SelectFromCollection(cstore.Certificates, title, message, X509SelectionFlag.SingleSelection);
if (certs.Count == 1)
{
X509Certificate2 mcert = certs[0] as X509Certificate2;
return mcert;
}
else
{
return null;
}
}
public static string EncryptWithCert(X509Certificate2 cert, string PlainText)
{
RSACryptoServiceProvider csp = cert.PublicKey.Key as RSACryptoServiceProvider;
byte[] PlainBytes = Convert.FromBase64String(PlainText);
// This converts the plain text into a byte array and then encrypts the raw bytes.
byte[] CryptoBytes = csp.Encrypt(PlainBytes, UseOAEP);
// This converts the encrypted bytes into a Base64 string.
string ReturnString = Convert.ToBase64String(CryptoBytes);
return ReturnString;
}
public static byte[] DecryptWithCert(X509Certificate2 cert, string EncryptedText)
{
RSACryptoServiceProvider csp = cert.PrivateKey as RSACryptoServiceProvider;
//CspParameters csps = new CspParameters();
byte[] EncryptedBytes = Convert.FromBase64String(EncryptedText);
// This converts the encrypted, Base64 encoded byte array from EncryptWithCert() to a byte[] and decrypts it.
byte[] CryptoBytes = csp.Decrypt(EncryptedBytes, UseOAEP);
return CryptoBytes;
}
public string Encrypt(string PlainText)
{
RijndaelManaged Algorithm = null;
string Output = null;
try
{
Rfc2898DeriveBytes PrivateKey = new Rfc2898DeriveBytes(this.EncryptionKey, this.Salt);
Algorithm = new RijndaelManaged();
Algorithm.Key = PrivateKey.GetBytes(Algorithm.KeySize / 8);
Algorithm.Padding = PaddingMode.PKCS7;
ICryptoTransform Encryption = Algorithm.CreateEncryptor(Algorithm.Key, Algorithm.IV);
using (MemoryStream msa = new MemoryStream())
{
msa.Write(BitConverter.GetBytes(Algorithm.IV.Length), 0, sizeof(int));
msa.Write(Algorithm.IV, 0, Algorithm.IV.Length);
using (CryptoStream csa = new CryptoStream(msa, Encryption, CryptoStreamMode.Write))
{
using (StreamWriter swa = new StreamWriter(csa))
{
swa.Write(PlainText);
}
}
Output = Convert.ToBase64String(msa.ToArray());
}
}
finally
{
if (Algorithm != null)
{
Algorithm.Clear();
}
}
return Output;
}
public string Decrypt(string EncryptedText)
{
RijndaelManaged Algorithm = null;
string Output = null;
try
{
Rfc2898DeriveBytes PrivateKey = new Rfc2898DeriveBytes(this.EncryptionKey, this.Salt);
byte[] KeyBytes = Convert.FromBase64String(EncryptedText);
using (MemoryStream msb = new MemoryStream(KeyBytes))
{
Algorithm = new RijndaelManaged();
Algorithm.Key = PrivateKey.GetBytes(Algorithm.KeySize / 8);
Algorithm.IV = ReadByteArray(msb);
Algorithm.Padding = PaddingMode.PKCS7;
ICryptoTransform Decryption = Algorithm.CreateDecryptor(Algorithm.Key, Algorithm.IV);
using (CryptoStream csb = new CryptoStream(msb, Decryption, CryptoStreamMode.Read))
{
using (StreamReader srb = new StreamReader(csb))
{
Output = srb.ReadToEnd();
}
}
}
}
finally
{
if (Algorithm != null)
{
Algorithm.Clear();
}
}
return Output;
}
public static string Sha512(string ToHash)
{
using (SHA512 SHA = new SHA512Managed())
{
byte[] HashByte = Encoding.UTF8.GetBytes(ToHash);
byte[] HashBytes = SHA.ComputeHash(HashByte);
string Hash = System.Text.Encoding.UTF8.GetString(HashBytes, 0, HashBytes.Length);
return Hash;
}
}
public static string Base64Encode(string data)
{
byte[] str = Encoding.UTF8.GetBytes(data);
return Convert.ToBase64String(str);
}
public static string Base64Decode(string data)
{
byte[] str = Convert.FromBase64String(data);
return Encoding.UTF8.GetString(str);
}
private byte[] ReadByteArray(Stream st)
{
byte[] Length = new byte[sizeof(int)];
st.Read(Length, 0, Length.Length);
byte[] Buffer = new byte[BitConverter.ToInt32(Length, 0)];
st.Read(Buffer, 0, Buffer.Length);
return Buffer;
}
}
}
确保您的密钥大小不会太小或太大。
查看来自 MSDN
的评论
The RSACryptoServiceProvider supports key sizes from 384 bits to 16384
bits in increments of 8 bits if you have the Microsoft Enhanced
Cryptographic Provider installed. It supports key sizes from 384 bits
to 512 bits in increments of 8 bits if you have the Microsoft Base
Cryptographic Provider installed.
因此您可能需要用一些字节填充短密钥字符串以获得最小密钥长度
好的，我设法检查了一下，据我所知，我的一些证书有问题。我不确定为什么有些证书有效而其他证书无效。最好知道为什么有些证书在这种情况下会失败？
无论如何，我使用 windows "Manage File Encryption Certificates" 创建了一个新的自签名证书并使用了这个证书，一切似乎都有效。
您的代码输出。
Encryption Key: aUc/GXWDoh2LktaEGeCJfju1dHP118yD/fzfT0iJLuhOq2QeyGpG6m3aBHaxvdH0ufeXRHbMjmlmPgIL/bhABzkT2C5Oa6ZhY3IFXb5t7JXZ3AtUunvtNAnRyFJ7MzklrSZGgQ
vF67DSNfIVE17doKt6j6mkCpSco56ooZCrOs2Mp3vSXqNjvjiwMEfQbk41aYUNVNVNlBGhdNQCIZIAKezQCUpWqzn2II27FIDfqDIEW4ieyzpXC05GzUlGXDxFOiFUPk3n0Y94vgeF8AlCD74eyZtz
WQ==
Encrypted Body: EAAAANS/W7+GGRbT1q5NCYvZlDZYtxaA8g55HzUqP5qxhenn
Encrypted Decryption Key: vc/tcsApmY1503BFi7oSu/RDvZivA1Ed58KJuLoEC6eE8q0BIa6ye2JvtXyxkVbzzL0MA51pZ2ZhMIsfCnBsEDjCgy+JLTZTGM1Mv+em9frFUKb0zHbICnPUa/3H
yd1yOWsdn5ws19QN2dzC6eau+ExhT2T/vyZO4Nf9NdHKnB8n2yB1rrQ/T+N2EYCNH/AVPDAsme6JG7k9Od2XIipBXMyCgXgWYZmQusq+JQjA9d3c4CrQYcg/ERF+K3oZv/gPicBkAR5taxwSxAajGg
bpkJNsbhTMHTN9bOn333qZ6ojlo5e882baZXuZWPr9qtj1b7ONoOyuSx/OvGKjt93BQg==
Decrypted Body: Hello World!
Output String: Hello World!.
希望对您有所帮助
我今天一直在用智能卡（或者更准确地说，是启用了智能卡 PIV 小程序的 Yubikey Neo）争论这个问题；使用此代码：
var encryptor = (RSACryptoServiceProvider)c.PublicKey.Key;
var decryptor = (RSACryptoServiceProvider)c.PrivateKey;
var encrypt = encryptor.Encrypt(bytes, RSAEncryptionPadding.Pkcs1);
var decrypt = decryptor.Decrypt(encrypt, RSAEncryptionPadding.Pkcs1);
我发现我使用的填充算法很重要。如果我使用 PKCS1 填充，一切正常。如果我使用 OaepSHA1，我会收到 Error while decoding [...] 错误。如果我使用其他任何东西（例如 OaepSHA256），我会收到 Not supported 错误。
我只能得出结论，我的智能卡不能正确支持 OAEP SHA1，但是用 PKCS#1 填充一切都很好。
即使这回答了您已知的问题，对于其他使用智能卡的人来说，它也可能用作另一个数据点。
我目前正在研究 class，它使用随机生成的加密密钥加密大量文本，该加密密钥由来自智能卡的 X509 证书加密，使用 RSACryptoServiceProvider 执行主密钥加密和解密操作。但是，当我将 fOEAP 填充选项设置为 true 时，每次解密时都会出现 "Error while decoding OAEP padding" 错误。我检查了密钥大小，它在可接受的范围内。我已经通过断点来确保从加密函数返回的 Base64 字符串与再次加载文件时传递回解密函数的加密 Base64 字符串完全相同。
密钥对绝对正确，因为没有 OAEP 也能正常工作。我也检查了文本编码。
编辑：事实证明这可能是智能卡特定问题，当我尝试使用本地 X509 证书解密时解密成功。
编辑：这是失败的解密代码：
string TestString = "Hello World!";
X509Certificate2 cert = DRXEncrypter.GetCertificate("Select a test certificate", "Select a certificate to use for this test from the local store.");
string key = DRXEncrypter.GenerateEncryptionKey(214);
Console.WriteLine("Encryption Key: " + key);
string encrypted = DRXEncrypter.EncryptBody(TestString, key);
Console.WriteLine("Encrypted Body: " + encrypted);
string cryptokey = DRXEncrypter.EncryptWithCert(cert, key);
Console.WriteLine("Encrypted Decryption Key: " + cryptokey);
string decrypted = DRXEncrypter.DecryptBody(encrypted, cryptokey, cert);
Console.WriteLine("Decrypted Body: " + decrypted);
Console.WriteLine("Output String: " + decrypted + ".");
这是我编写的来自加密提供商 class 的代码。我已经在这个问题上停留了几个小时，所以如果有人能帮助我就太好了。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.IO;
namespace CoreDRXEditor
{
public class DRXEncrypter
{
private byte[] Salt = Encoding.ASCII.GetBytes("81PO9j8I1a94j");
private string EncryptionKey;
private const bool UseOAEP = true;
public DRXEncrypter(string EncryptionKey)
{
this.EncryptionKey = EncryptionKey;
}
public static string EncryptBody(string body, string encryptionkey)
{
// Use the plaintext master key to encrypt the body.
DRXEncrypter enc = new DRXEncrypter(encryptionkey);
// Encrypt the body.
return enc.Encrypt(body);
}
public static int GetMaxKeySize(X509Certificate2 cert)
{
RSACryptoServiceProvider csp = cert.PublicKey.Key as RSACryptoServiceProvider;
return csp.KeySize;
}
public static string DecryptBody(string body, string encryptionkey, X509Certificate2 cert)
{
// Decrypt the encrypted encryption key with the certificate.
string DecryptedKey = Convert.ToBase64String(DecryptWithCert(cert, encryptionkey));
// Create a new DRXEncrypter using the decrypted encryption key to decrypt the body.
DRXEncrypter enc = new DRXEncrypter(DecryptedKey);
// Return the decrypted body.
return enc.Decrypt(body);
}
public static string GenerateEncryptionKey(int KeyLength)
{
using (RandomNumberGenerator rng = new RNGCryptoServiceProvider())
{
byte[] CryptoBytes = new byte[KeyLength];
rng.GetBytes(CryptoBytes);
return Convert.ToBase64String(CryptoBytes);
}
}
public static X509Certificate2 GetCertificate(string title, string message)
{
X509Store cstore = new X509Store(StoreLocation.CurrentUser);
cstore.Open(OpenFlags.ReadOnly);
X509CertificateCollection certs = X509Certificate2UI.SelectFromCollection(cstore.Certificates, title, message, X509SelectionFlag.SingleSelection);
if (certs.Count == 1)
{
X509Certificate2 mcert = certs[0] as X509Certificate2;
return mcert;
}
else
{
return null;
}
}
public static string EncryptWithCert(X509Certificate2 cert, string PlainText)
{
RSACryptoServiceProvider csp = cert.PublicKey.Key as RSACryptoServiceProvider;
byte[] PlainBytes = Convert.FromBase64String(PlainText);
// This converts the plain text into a byte array and then encrypts the raw bytes.
byte[] CryptoBytes = csp.Encrypt(PlainBytes, UseOAEP);
// This converts the encrypted bytes into a Base64 string.
string ReturnString = Convert.ToBase64String(CryptoBytes);
return ReturnString;
}
public static byte[] DecryptWithCert(X509Certificate2 cert, string EncryptedText)
{
RSACryptoServiceProvider csp = cert.PrivateKey as RSACryptoServiceProvider;
//CspParameters csps = new CspParameters();
byte[] EncryptedBytes = Convert.FromBase64String(EncryptedText);
// This converts the encrypted, Base64 encoded byte array from EncryptWithCert() to a byte[] and decrypts it.
byte[] CryptoBytes = csp.Decrypt(EncryptedBytes, UseOAEP);
return CryptoBytes;
}
public string Encrypt(string PlainText)
{
RijndaelManaged Algorithm = null;
string Output = null;
try
{
Rfc2898DeriveBytes PrivateKey = new Rfc2898DeriveBytes(this.EncryptionKey, this.Salt);
Algorithm = new RijndaelManaged();
Algorithm.Key = PrivateKey.GetBytes(Algorithm.KeySize / 8);
Algorithm.Padding = PaddingMode.PKCS7;
ICryptoTransform Encryption = Algorithm.CreateEncryptor(Algorithm.Key, Algorithm.IV);
using (MemoryStream msa = new MemoryStream())
{
msa.Write(BitConverter.GetBytes(Algorithm.IV.Length), 0, sizeof(int));
msa.Write(Algorithm.IV, 0, Algorithm.IV.Length);
using (CryptoStream csa = new CryptoStream(msa, Encryption, CryptoStreamMode.Write))
{
using (StreamWriter swa = new StreamWriter(csa))
{
swa.Write(PlainText);
}
}
Output = Convert.ToBase64String(msa.ToArray());
}
}
finally
{
if (Algorithm != null)
{
Algorithm.Clear();
}
}
return Output;
}
public string Decrypt(string EncryptedText)
{
RijndaelManaged Algorithm = null;
string Output = null;
try
{
Rfc2898DeriveBytes PrivateKey = new Rfc2898DeriveBytes(this.EncryptionKey, this.Salt);
byte[] KeyBytes = Convert.FromBase64String(EncryptedText);
using (MemoryStream msb = new MemoryStream(KeyBytes))
{
Algorithm = new RijndaelManaged();
Algorithm.Key = PrivateKey.GetBytes(Algorithm.KeySize / 8);
Algorithm.IV = ReadByteArray(msb);
Algorithm.Padding = PaddingMode.PKCS7;
ICryptoTransform Decryption = Algorithm.CreateDecryptor(Algorithm.Key, Algorithm.IV);
using (CryptoStream csb = new CryptoStream(msb, Decryption, CryptoStreamMode.Read))
{
using (StreamReader srb = new StreamReader(csb))
{
Output = srb.ReadToEnd();
}
}
}
}
finally
{
if (Algorithm != null)
{
Algorithm.Clear();
}
}
return Output;
}
public static string Sha512(string ToHash)
{
using (SHA512 SHA = new SHA512Managed())
{
byte[] HashByte = Encoding.UTF8.GetBytes(ToHash);
byte[] HashBytes = SHA.ComputeHash(HashByte);
string Hash = System.Text.Encoding.UTF8.GetString(HashBytes, 0, HashBytes.Length);
return Hash;
}
}
public static string Base64Encode(string data)
{
byte[] str = Encoding.UTF8.GetBytes(data);
return Convert.ToBase64String(str);
}
public static string Base64Decode(string data)
{
byte[] str = Convert.FromBase64String(data);
return Encoding.UTF8.GetString(str);
}
private byte[] ReadByteArray(Stream st)
{
byte[] Length = new byte[sizeof(int)];
st.Read(Length, 0, Length.Length);
byte[] Buffer = new byte[BitConverter.ToInt32(Length, 0)];
st.Read(Buffer, 0, Buffer.Length);
return Buffer;
}
}
}
确保您的密钥大小不会太小或太大。
查看来自 MSDN
的评论The RSACryptoServiceProvider supports key sizes from 384 bits to 16384 bits in increments of 8 bits if you have the Microsoft Enhanced Cryptographic Provider installed. It supports key sizes from 384 bits to 512 bits in increments of 8 bits if you have the Microsoft Base Cryptographic Provider installed.
因此您可能需要用一些字节填充短密钥字符串以获得最小密钥长度
好的，我设法检查了一下，据我所知，我的一些证书有问题。我不确定为什么有些证书有效而其他证书无效。最好知道为什么有些证书在这种情况下会失败？
无论如何，我使用 windows "Manage File Encryption Certificates" 创建了一个新的自签名证书并使用了这个证书，一切似乎都有效。
您的代码输出。
Encryption Key: aUc/GXWDoh2LktaEGeCJfju1dHP118yD/fzfT0iJLuhOq2QeyGpG6m3aBHaxvdH0ufeXRHbMjmlmPgIL/bhABzkT2C5Oa6ZhY3IFXb5t7JXZ3AtUunvtNAnRyFJ7MzklrSZGgQ
vF67DSNfIVE17doKt6j6mkCpSco56ooZCrOs2Mp3vSXqNjvjiwMEfQbk41aYUNVNVNlBGhdNQCIZIAKezQCUpWqzn2II27FIDfqDIEW4ieyzpXC05GzUlGXDxFOiFUPk3n0Y94vgeF8AlCD74eyZtz
WQ==
Encrypted Body: EAAAANS/W7+GGRbT1q5NCYvZlDZYtxaA8g55HzUqP5qxhenn
Encrypted Decryption Key: vc/tcsApmY1503BFi7oSu/RDvZivA1Ed58KJuLoEC6eE8q0BIa6ye2JvtXyxkVbzzL0MA51pZ2ZhMIsfCnBsEDjCgy+JLTZTGM1Mv+em9frFUKb0zHbICnPUa/3H
yd1yOWsdn5ws19QN2dzC6eau+ExhT2T/vyZO4Nf9NdHKnB8n2yB1rrQ/T+N2EYCNH/AVPDAsme6JG7k9Od2XIipBXMyCgXgWYZmQusq+JQjA9d3c4CrQYcg/ERF+K3oZv/gPicBkAR5taxwSxAajGg
bpkJNsbhTMHTN9bOn333qZ6ojlo5e882baZXuZWPr9qtj1b7ONoOyuSx/OvGKjt93BQg==
Decrypted Body: Hello World!
Output String: Hello World!.
希望对您有所帮助
我今天一直在用智能卡（或者更准确地说，是启用了智能卡 PIV 小程序的 Yubikey Neo）争论这个问题；使用此代码：
var encryptor = (RSACryptoServiceProvider)c.PublicKey.Key;
var decryptor = (RSACryptoServiceProvider)c.PrivateKey;
var encrypt = encryptor.Encrypt(bytes, RSAEncryptionPadding.Pkcs1);
var decrypt = decryptor.Decrypt(encrypt, RSAEncryptionPadding.Pkcs1);
我发现我使用的填充算法很重要。如果我使用 PKCS1 填充，一切正常。如果我使用 OaepSHA1，我会收到 Error while decoding [...] 错误。如果我使用其他任何东西（例如 OaepSHA256），我会收到 Not supported 错误。
我只能得出结论，我的智能卡不能正确支持 OAEP SHA1，但是用 PKCS#1 填充一切都很好。
即使这回答了您已知的问题，对于其他使用智能卡的人来说，它也可能用作另一个数据点。