如何在 C# 中从文件中加载 RSA 公钥
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【中文标题】如何在 C# 中从文件中加载 RSA 公钥【英文标题】：How to load the RSA public key from file in C# 【发布时间】：2012-07-15 10:52:32 【问题描述】：我需要从文件中加载以下 RSA 公钥以用于 RSACryptoServiceProvider 类。我该怎么做？
-----BEGIN PUBLIC KEY-----
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX/syEKqEkMtQL0+d
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX+izR
KbGMRtur2TYklnyVkjeeHfAggo8vWQmWesnOG55vQYHbOOFoJbk0EkwEr5R/PbKm
byXPPN8zwnS5/XXXXXXXXXXXX
-----END PUBLIC KEY-----
此代码适用于我的 pub 密钥：http://www.jensign.com/opensslkey/
这是我正在使用的代码
static string RSA(string input)
RSACryptoServiceProvider rsa = DecodeX509PublicKey(Convert.FromBase64String(GetKey()));
return (Convert.ToBase64String(rsa.Encrypt(Encoding.ASCII.GetBytes(input), false)));
static string GetKey()
return File.ReadAllText("master.pub").Replace("-----BEGIN PUBLIC KEY-----", "").Replace("-----END PUBLIC KEY-----", "");
//.Replace("\n", "");
private static bool CompareBytearrays(byte[] a, byte[] b)
if (a.Length != b.Length)
return false;
int i = 0;
foreach (byte c in a)
if (c != b[i])
return false;
i++;
return true;
public static RSACryptoServiceProvider DecodeX509PublicKey(byte[] x509key)
// encoded OID sequence for PKCS #1 rsaEncryption szOID_RSA_RSA = "1.2.840.113549.1.1.1"
byte[] SeqOID = 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00 ;
byte[] seq = new byte[15];
// --------- Set up stream to read the asn.1 encoded SubjectPublicKeyInfo blob ------
MemoryStream mem = new MemoryStream(x509key);
BinaryReader binr = new BinaryReader(mem); //wrap Memory Stream with BinaryReader for easy reading
byte bt = 0;
ushort twobytes = 0;
try
twobytes = binr.ReadUInt16();
if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
binr.ReadByte(); //advance 1 byte
else if (twobytes == 0x8230)
binr.ReadInt16(); //advance 2 bytes
else
return null;
seq = binr.ReadBytes(15); //read the Sequence OID
if (!CompareBytearrays(seq, SeqOID)) //make sure Sequence for OID is correct
return null;
twobytes = binr.ReadUInt16();
if (twobytes == 0x8103) //data read as little endian order (actual data order for Bit String is 03 81)
binr.ReadByte(); //advance 1 byte
else if (twobytes == 0x8203)
binr.ReadInt16(); //advance 2 bytes
else
return null;
bt = binr.ReadByte();
if (bt != 0x00) //expect null byte next
return null;
twobytes = binr.ReadUInt16();
if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
binr.ReadByte(); //advance 1 byte
else if (twobytes == 0x8230)
binr.ReadInt16(); //advance 2 bytes
else
return null;
twobytes = binr.ReadUInt16();
byte lowbyte = 0x00;
byte highbyte = 0x00;
if (twobytes == 0x8102) //data read as little endian order (actual data order for Integer is 02 81)
lowbyte = binr.ReadByte(); // read next bytes which is bytes in modulus
else if (twobytes == 0x8202)
highbyte = binr.ReadByte(); //advance 2 bytes
lowbyte = binr.ReadByte();
else
return null;
byte[] modint = lowbyte, highbyte, 0x00, 0x00 ; //reverse byte order since asn.1 key uses big endian order
int modsize = BitConverter.ToInt32(modint, 0);
byte firstbyte = binr.ReadByte();
binr.BaseStream.Seek(-1, SeekOrigin.Current);
if (firstbyte == 0x00)
//if first byte (highest order) of modulus is zero, don't include it
binr.ReadByte(); //skip this null byte
modsize -= 1; //reduce modulus buffer size by 1
byte[] modulus = binr.ReadBytes(modsize); //read the modulus bytes
if (binr.ReadByte() != 0x02) //expect an Integer for the exponent data
return null;
int expbytes = (int)binr.ReadByte(); // should only need one byte for actual exponent data (for all useful values)
byte[] exponent = binr.ReadBytes(expbytes);
// ------- create RSACryptoServiceProvider instance and initialize with public key -----
RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
RSAParameters RSAKeyInfo = new RSAParameters();
RSAKeyInfo.Modulus = modulus;
RSAKeyInfo.Exponent = exponent;
RSA.ImportParameters(RSAKeyInfo);
return RSA;
catch (Exception)
return null;
finally binr.Close();
只需使用要加密的文本调用“RSA”方法即可。
【问题讨论】：
使用IO.StreamReader?
可能重复？ ***.com/questions/243646/…
我尝试使用 Convert.FromBase64String 将字符串转换为字节，然后将字节传递给 RSACryptoServiceProvider 构造函数，但它会引发异常。 X509Certificate.CreateFromFile 也会发生同样的情况
也许您可以先尝试针对已知的有效公钥文件测试您的代码，然后针对您上面的密钥进行测试。
我现在使用下面的代码jensign.com/opensslkey 似乎可以工作...
【参考方案1】：
您可以使用以下类（GetRSAProviderFromPemFile 方法）从 PEM 文件创建 RSACryptoServiceProvider。
警告： 不要未经验证就从 *** 复制代码！尤其不是加密代码！此代码有错误（请参阅 cmets）。您可能希望在生产中使用它之前编写和运行测试（如果您真的没有更好的选择）。我拒绝编辑代码来修复它，因为如果没有测试和积极的维护者。
来源：
这段代码似乎取自opensslkey 来自this site。
版权所有 (c) 2000 JavaScience Consulting, Michel Gallant。
原始包是在类似 BSD 的许可证下发布的，因此使用它可能是可以的（但您可能需要仔细检查）。还有一个NuGet package是同一作者的。
这是最初发布到此答案的复制粘贴源代码：
RSACryptoServiceProvider provider = PemKeyUtils.GetRSAProviderFromPemFile( @"public_key.pem" );
public class PemKeyUtils
const String pemprivheader = "-----BEGIN RSA PRIVATE KEY-----";
const String pemprivfooter = "-----END RSA PRIVATE KEY-----";
const String pempubheader = "-----BEGIN PUBLIC KEY-----";
const String pempubfooter = "-----END PUBLIC KEY-----";
const String pemp8header = "-----BEGIN PRIVATE KEY-----";
const String pemp8footer = "-----END PRIVATE KEY-----";
const String pemp8encheader = "-----BEGIN ENCRYPTED PRIVATE KEY-----";
const String pemp8encfooter = "-----END ENCRYPTED PRIVATE KEY-----";
static bool verbose = false;
public static RSACryptoServiceProvider GetRSAProviderFromPemFile( String pemfile )
bool isPrivateKeyFile = true;
string pemstr = File.ReadAllText( pemfile ).Trim();
if (pemstr.StartsWith( pempubheader ) && pemstr.EndsWith( pempubfooter ))
isPrivateKeyFile = false;
byte[] pemkey;
if (isPrivateKeyFile)
pemkey = DecodeOpenSSLPrivateKey( pemstr );
else
pemkey = DecodeOpenSSLPublicKey( pemstr );
if (pemkey == null)
return null;
if (isPrivateKeyFile)
return DecodeRSAPrivateKey( pemkey );
else
return DecodeX509PublicKey( pemkey );
//-------- Get the binary RSA PUBLIC key --------
static byte[] DecodeOpenSSLPublicKey( String instr )
const String pempubheader = "-----BEGIN PUBLIC KEY-----";
const String pempubfooter = "-----END PUBLIC KEY-----";
String pemstr = instr.Trim();
byte[] binkey;
if (!pemstr.StartsWith( pempubheader ) || !pemstr.EndsWith( pempubfooter ))
return null;
StringBuilder sb = new StringBuilder( pemstr );
sb.Replace( pempubheader, "" ); //remove headers/footers, if present
sb.Replace( pempubfooter, "" );
String pubstr = sb.ToString().Trim(); //get string after removing leading/trailing whitespace
try
binkey = Convert.FromBase64String( pubstr );
catch (System.FormatException)
//if can't b64 decode, data is not valid
return null;
return binkey;
static RSACryptoServiceProvider DecodeX509PublicKey(byte[] x509Key)
// encoded OID sequence for PKCS #1 rsaEncryption szOID_RSA_RSA = "1.2.840.113549.1.1.1"
byte[] seqOid = 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00 ;
// --------- Set up stream to read the asn.1 encoded SubjectPublicKeyInfo blob ------
using (var mem = new MemoryStream(x509Key))
using (var binr = new BinaryReader(mem)) //wrap Memory Stream with BinaryReader for easy reading
try
var twobytes = binr.ReadUInt16();
switch (twobytes)
case 0x8130:
binr.ReadByte(); //advance 1 byte
break;
case 0x8230:
binr.ReadInt16(); //advance 2 bytes
break;
default:
return null;
var seq = binr.ReadBytes(15);
if (!CompareBytearrays(seq, seqOid)) //make sure Sequence for OID is correct
return null;
twobytes = binr.ReadUInt16();
if (twobytes == 0x8103) //data read as little endian order (actual data order for Bit String is 03 81)
binr.ReadByte(); //advance 1 byte
else if (twobytes == 0x8203)
binr.ReadInt16(); //advance 2 bytes
else
return null;
var bt = binr.ReadByte();
if (bt != 0x00) //expect null byte next
return null;
twobytes = binr.ReadUInt16();
if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
binr.ReadByte(); //advance 1 byte
else if (twobytes == 0x8230)
binr.ReadInt16(); //advance 2 bytes
else
return null;
twobytes = binr.ReadUInt16();
byte lowbyte = 0x00;
byte highbyte = 0x00;
if (twobytes == 0x8102) //data read as little endian order (actual data order for Integer is 02 81)
lowbyte = binr.ReadByte(); // read next bytes which is bytes in modulus
else if (twobytes == 0x8202)
highbyte = binr.ReadByte(); //advance 2 bytes
lowbyte = binr.ReadByte();
else
return null;
byte[] modint = lowbyte, highbyte, 0x00, 0x00 ; //reverse byte order since asn.1 key uses big endian order
int modsize = BitConverter.ToInt32(modint, 0);
byte firstbyte = binr.ReadByte();
binr.BaseStream.Seek(-1, SeekOrigin.Current);
if (firstbyte == 0x00)
//if first byte (highest order) of modulus is zero, don't include it
binr.ReadByte(); //skip this null byte
modsize -= 1; //reduce modulus buffer size by 1
byte[] modulus = binr.ReadBytes(modsize); //read the modulus bytes
if (binr.ReadByte() != 0x02) //expect an Integer for the exponent data
return null;
int expbytes = binr.ReadByte(); // should only need one byte for actual exponent data (for all useful values)
byte[] exponent = binr.ReadBytes(expbytes);
// We don't really need to print anything but if we insist to...
//showBytes("\nExponent", exponent);
//showBytes("\nModulus", modulus);
// ------- create RSACryptoServiceProvider instance and initialize with public key -----
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
RSAParameters rsaKeyInfo = new RSAParameters
Modulus = modulus,
Exponent = exponent
;
rsa.ImportParameters(rsaKeyInfo);
return rsa;
catch (Exception)
return null;
//------- Parses binary ans.1 RSA private key; returns RSACryptoServiceProvider ---
static RSACryptoServiceProvider DecodeRSAPrivateKey( byte[] privkey )
byte[] MODULUS, E, D, P, Q, DP, DQ, IQ;
// --------- Set up stream to decode the asn.1 encoded RSA private key ------
MemoryStream mem = new MemoryStream( privkey );
BinaryReader binr = new BinaryReader( mem ); //wrap Memory Stream with BinaryReader for easy reading
byte bt = 0;
ushort twobytes = 0;
int elems = 0;
try
twobytes = binr.ReadUInt16();
if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
binr.ReadByte(); //advance 1 byte
else if (twobytes == 0x8230)
binr.ReadInt16(); //advance 2 bytes
else
return null;
twobytes = binr.ReadUInt16();
if (twobytes != 0x0102) //version number
return null;
bt = binr.ReadByte();
if (bt != 0x00)
return null;
//------ all private key components are Integer sequences ----
elems = GetIntegerSize( binr );
MODULUS = binr.ReadBytes( elems );
elems = GetIntegerSize( binr );
E = binr.ReadBytes( elems );
elems = GetIntegerSize( binr );
D = binr.ReadBytes( elems );
elems = GetIntegerSize( binr );
P = binr.ReadBytes( elems );
elems = GetIntegerSize( binr );
Q = binr.ReadBytes( elems );
elems = GetIntegerSize( binr );
DP = binr.ReadBytes( elems );
elems = GetIntegerSize( binr );
DQ = binr.ReadBytes( elems );
elems = GetIntegerSize( binr );
IQ = binr.ReadBytes( elems );
Console.WriteLine( "showing components .." );
if (verbose)
showBytes( "\nModulus", MODULUS );
showBytes( "\nExponent", E );
showBytes( "\nD", D );
showBytes( "\nP", P );
showBytes( "\nQ", Q );
showBytes( "\nDP", DP );
showBytes( "\nDQ", DQ );
showBytes( "\nIQ", IQ );
// ------- create RSACryptoServiceProvider instance and initialize with public key -----
RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
RSAParameters RSAparams = new RSAParameters();
RSAparams.Modulus = MODULUS;
RSAparams.Exponent = E;
RSAparams.D = D;
RSAparams.P = P;
RSAparams.Q = Q;
RSAparams.DP = DP;
RSAparams.DQ = DQ;
RSAparams.InverseQ = IQ;
RSA.ImportParameters( RSAparams );
return RSA;
catch (Exception)
return null;
finally binr.Close();
private static int GetIntegerSize( BinaryReader binr )
byte bt = 0;
byte lowbyte = 0x00;
byte highbyte = 0x00;
int count = 0;
bt = binr.ReadByte();
if (bt != 0x02) //expect integer
return 0;
bt = binr.ReadByte();
if (bt == 0x81)
count = binr.ReadByte(); // data size in next byte
else
if (bt == 0x82)
highbyte = binr.ReadByte(); // data size in next 2 bytes
lowbyte = binr.ReadByte();
byte[] modint = lowbyte, highbyte, 0x00, 0x00 ;
count = BitConverter.ToInt32( modint, 0 );
else
count = bt; // we already have the data size
while (binr.ReadByte() == 0x00)
//remove high order zeros in data
count -= 1;
binr.BaseStream.Seek( -1, SeekOrigin.Current ); //last ReadByte wasn't a removed zero, so back up a byte
return count;
//----- Get the binary RSA PRIVATE key, decrypting if necessary ----
static byte[] DecodeOpenSSLPrivateKey( String instr )
const String pemprivheader = "-----BEGIN RSA PRIVATE KEY-----";
const String pemprivfooter = "-----END RSA PRIVATE KEY-----";
String pemstr = instr.Trim();
byte[] binkey;
if (!pemstr.StartsWith( pemprivheader ) || !pemstr.EndsWith( pemprivfooter ))
return null;
StringBuilder sb = new StringBuilder( pemstr );
sb.Replace( pemprivheader, "" ); //remove headers/footers, if present
sb.Replace( pemprivfooter, "" );
String pvkstr = sb.ToString().Trim(); //get string after removing leading/trailing whitespace
try
// if there are no PEM encryption info lines, this is an UNencrypted PEM private key
binkey = Convert.FromBase64String( pvkstr );
return binkey;
catch (System.FormatException)
//if can't b64 decode, it must be an encrypted private key
//Console.WriteLine("Not an unencrypted OpenSSL PEM private key");
StringReader str = new StringReader( pvkstr );
//-------- read PEM encryption info. lines and extract salt -----
if (!str.ReadLine().StartsWith( "Proc-Type: 4,ENCRYPTED" ))
return null;
String saltline = str.ReadLine();
if (!saltline.StartsWith( "DEK-Info: DES-EDE3-CBC," ))
return null;
String saltstr = saltline.Substring( saltline.IndexOf( "," ) + 1 ).Trim();
byte[] salt = new byte[saltstr.Length / 2];
for (int i = 0; i < salt.Length; i++)
salt[i] = Convert.ToByte( saltstr.Substring( i * 2, 2 ), 16 );
if (!(str.ReadLine() == ""))
return null;
//------ remaining b64 data is encrypted RSA key ----
String encryptedstr = str.ReadToEnd();
try
//should have b64 encrypted RSA key now
binkey = Convert.FromBase64String( encryptedstr );
catch (System.FormatException)
// bad b64 data.
return null;
//------ Get the 3DES 24 byte key using PDK used by OpenSSL ----
SecureString despswd = GetSecPswd( "Enter password to derive 3DES key==>" );
//Console.Write("\nEnter password to derive 3DES key: ");
//String pswd = Console.ReadLine();
byte[] deskey = GetOpenSSL3deskey( salt, despswd, 1, 2 ); // count=1 (for OpenSSL implementation); 2 iterations to get at least 24 bytes
if (deskey == null)
return null;
//showBytes("3DES key", deskey) ;
//------ Decrypt the encrypted 3des-encrypted RSA private key ------
byte[] rsakey = DecryptKey( binkey, deskey, salt ); //OpenSSL uses salt value in PEM header also as 3DES IV
if (rsakey != null)
return rsakey; //we have a decrypted RSA private key
else
Console.WriteLine( "Failed to decrypt RSA private key; probably wrong password." );
return null;
// ----- Decrypt the 3DES encrypted RSA private key ----------
static byte[] DecryptKey( byte[] cipherData, byte[] desKey, byte[] IV )
MemoryStream memst = new MemoryStream();
TripleDES alg = TripleDES.Create();
alg.Key = desKey;
alg.IV = IV;
try
CryptoStream cs = new CryptoStream( memst, alg.CreateDecryptor(), CryptoStreamMode.Write );
cs.Write( cipherData, 0, cipherData.Length );
cs.Close();
catch (Exception exc)
Console.WriteLine( exc.Message );
return null;
byte[] decryptedData = memst.ToArray();
return decryptedData;
//----- OpenSSL PBKD uses only one hash cycle (count); miter is number of iterations required to build sufficient bytes ---
static byte[] GetOpenSSL3deskey( byte[] salt, SecureString secpswd, int count, int miter )
IntPtr unmanagedPswd = IntPtr.Zero;
int HASHLENGTH = 16; //MD5 bytes
byte[] keymaterial = new byte[HASHLENGTH * miter]; //to store contatenated Mi hashed results
byte[] psbytes = new byte[secpswd.Length];
unmanagedPswd = Marshal.SecureStringToGlobalAllocAnsi( secpswd );
Marshal.Copy( unmanagedPswd, psbytes, 0, psbytes.Length );
Marshal.ZeroFreeGlobalAllocAnsi( unmanagedPswd );
//UTF8Encoding utf8 = new UTF8Encoding();
//byte[] psbytes = utf8.GetBytes(pswd);
// --- contatenate salt and pswd bytes into fixed data array ---
byte[] data00 = new byte[psbytes.Length + salt.Length];
Array.Copy( psbytes, data00, psbytes.Length ); //copy the pswd bytes
Array.Copy( salt, 0, data00, psbytes.Length, salt.Length ); //concatenate the salt bytes
// ---- do multi-hashing and contatenate results D1, D2 ... into keymaterial bytes ----
MD5 md5 = new MD5CryptoServiceProvider();
byte[] result = null;
byte[] hashtarget = new byte[HASHLENGTH + data00.Length]; //fixed length initial hashtarget
for (int j = 0; j < miter; j++)
// ---- Now hash consecutively for count times ------
if (j == 0)
result = data00; //initialize
else
Array.Copy( result, hashtarget, result.Length );
Array.Copy( data00, 0, hashtarget, result.Length, data00.Length );
result = hashtarget;
//Console.WriteLine("Updated new initial hash target:") ;
//showBytes(result) ;
for (int i = 0; i < count; i++)
result = md5.ComputeHash( result );
Array.Copy( result, 0, keymaterial, j * HASHLENGTH, result.Length ); //contatenate to keymaterial
//showBytes("Final key material", keymaterial);
byte[] deskey = new byte[24];
Array.Copy( keymaterial, deskey, deskey.Length );
Array.Clear( psbytes, 0, psbytes.Length );
Array.Clear( data00, 0, data00.Length );
Array.Clear( result, 0, result.Length );
Array.Clear( hashtarget, 0, hashtarget.Length );
Array.Clear( keymaterial, 0, keymaterial.Length );
return deskey;
static SecureString GetSecPswd( String prompt )
SecureString password = new SecureString();
Console.ForegroundColor = ConsoleColor.Gray;
Console.Write( prompt );
Console.ForegroundColor = ConsoleColor.Magenta;
while (true)
ConsoleKeyInfo cki = Console.ReadKey( true );
if (cki.Key == ConsoleKey.Enter)
Console.ForegroundColor = ConsoleColor.Gray;
Console.WriteLine();
return password;
else if (cki.Key == ConsoleKey.Backspace)
// remove the last asterisk from the screen...
if (password.Length > 0)
Console.SetCursorPosition( Console.CursorLeft - 1, Console.CursorTop );
Console.Write( " " );
Console.SetCursorPosition( Console.CursorLeft - 1, Console.CursorTop );
password.RemoveAt( password.Length - 1 );
else if (cki.Key == ConsoleKey.Escape)
Console.ForegroundColor = ConsoleColor.Gray;
Console.WriteLine();
return password;
else if (Char.IsLetterOrDigit( cki.KeyChar ) || Char.IsSymbol( cki.KeyChar ))
if (password.Length < 20)
password.AppendChar( cki.KeyChar );
Console.Write( "*" );
else
Console.Beep();
else
Console.Beep();
static bool CompareBytearrays( byte[] a, byte[] b )
if (a.Length != b.Length)
return false;
int i = 0;
foreach (byte c in a)
if (c != b[i])
return false;
i++;
return true;
static void showBytes( String info, byte[] data )
Console.WriteLine( "0 [1 bytes]", info, data.Length );
for (int i = 1; i <= data.Length; i++)
Console.Write( "0:X2 ", data[i - 1] );
if (i % 16 == 0)
Console.WriteLine();
Console.WriteLine( "\n\n" );
【讨论】：
很抱歉，OP 没有将您的答案标记为已接受。这是一个非常好的。 嗯...例如，这个openssl键不起作用，也不是来自某些库，你可以看看：github.com/dvsekhvalnov/jose-jwt/issues/…^^' 此代码（尤其是在GetIntegerSize 中跳过前导零）会由于值太短而导致ImportParameters 中的CryptographicException。它只是偶尔发生。由于值太长，不跳过前导零可能会导致相同的异常。如果不跳过GetIntegerSize 中的前导零，值是否会变得太短尚不清楚，因为这取决于输入。有关详细信息，请参阅 ***.com/a/39135984/2279059。
字符串 private_key = File.ReadAllText(private_key_file).Trim();正则表达式 regex = new Regex(@"-----(BEGIN|END) (RSA|OPENSSH|ENCRYPTED) PRIVATE KEY-----[\W]*"); string private_key_base64 = regex.Replace(private_key, ""); byte[] bytes_privake_key = Convert.FromBase64String(private_key_base64); rsa.ImportRSAPrivateKey(new ReadOnlySpan如果您说的是 X509 证书：
FileStream fs = new FileStream("your_cert_file.crt", FileMode.Open);
byte[] certBytes = new byte[fs.Length];
fs.Read(certBytes, 0, (Int32)fs.Length);
fs.Close();
System.Security.Cryptography.X509Certificates.X509Certificate x509cert =
new X509Certificate(certBytes);
Console.WriteLine(x509cert.GetPublicKey());
Console.WriteLine(x509cert.GetPublicKeyString());
在“7/16/2012 15:04:58 Z”中完成@hkproj 的评论后编辑：
环顾四周，我找到了“Reading PEM RSA Public Key Only using Bouncy Castle”。 我想你想要的是这样的：
using (StreamReader reader = File.OpenText(@"c:\RSA.txt"))
Org.BouncyCastle.OpenSsl.PemReader pr =
new Org.BouncyCastle.OpenSsl.PemReader(reader);
Org.BouncyCastle.Utilities.IO.Pem.PemObject po = pr.ReadPemObject();
Console.WriteLine("PemObject, Type: " + po.Type);
Console.WriteLine("PemObject, Length: " + po.Content.Length);
但是，对于您的文件，我收到一个错误：System.IO.IOException : base64 data appears to be truncated。
因此将您的文件更改为：
-----BEGIN PUBLIC KEY-----
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX/syEKqEkMtQL0+d
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX+izR
KbGMRtur2TYklnyVkjeeHfAggo8vWQmWesnOG55vQYHbOOFoJbk0EkwEr5R/PbKm
byXPPN8zwnS5/XXXXXXXXXXXXZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
-----END PUBLIC KEY-----
结果是：
PemObject, Type: PUBLIC KEY
PemObject, Length: 192
【讨论】：
已经试过了。没用。抛出“CryptographicException”并显示以下消息：找不到请求的对象。【参考方案3】：您是在谈论存储在文件中的证书吗？
如果你有这样的对象：
X509Certificate2 certificate;
您可以使用以下代码：
RSACryptoServiceProvider rsaprovider =
(RSACryptoServiceProvider)certificate.PublicKey.Key;
然后使用类 RSACryptoServiceProvider（参见http://msdn.microsoft.com/en-us/library/system.security.cryptography.rsacryptoserviceprovider.aspx）。
要加载 X509Certificate2，请使用其构造函数（请参阅http://msdn.microsoft.com/en-us/library/system.security.cryptography.x509certificates.x509certificate2.aspx）。
这个程序对我来说很好用：
static void Main(string[] args)
try
X509Certificate2 certificate =
new X509Certificate2("<PFX Certificate Path", "<Certificate-Password>");
RSACryptoServiceProvider rsaprovider = (RSACryptoServiceProvider)certificate.PublicKey.Key;
catch(Exception e)
【讨论】：
抛出 'CryptographicException' 并显示此消息：找不到请求的对象 我知道构造函数等待二进制证书（DER 格式），而不是 base64 一个...阅读您的解决方案我注意到这个“FromBase64String”所以您使用的是 Base64 二进制格式？ 证书保存为base64格式。所以我使用 FromBase64String 将其转换为字节数组，以便可以将其传递给构造函数。顺便说一句，我解决了。如果您查看我的解决方案，我正在使用一种从“opensslkey”工具（它是开源的）中“窃取”的方法。希望对您有所帮助。【参考方案4】：从 .Net 5.0 开始，您可以像这样从字符串中导入 RSA 公钥：
var rsaPublicKey = RSA.Create();
rsaPublicKey.ImportFromPem(publicKeyString);
如果您不知道如何将文件读取到字符串，请参阅
How to read an entire file to a string using C#?
【讨论】：
【参考方案5】：string private_key = File.ReadAllText(private_key_file).Trim();
Regex regex = new Regex(@"-----(BEGIN|END) (RSA|OPENSSH|ENCRYPTED) PRIVATE KEY-----[\W]*");
string private_key_base64 = regex.Replace(private_key, "");
byte[] bytes_privake_key = Convert.FromBase64String(private_key_base64);
rsa.ImportRSAPrivateKey(new ReadOnlySpan<byte>(bytes_privake_key), out bytesRead);
【讨论】：
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