不幸的是，您所引用的答案中的代码并不是真正正确的-它导出 私钥 PEM格式，但是仅正确设置了公钥字段，这与以标准格式导出RSA公钥不同。
我实际上是在该问题的另一个答案中编写代码的，当时我编写了一种以标准格式导出公钥的模式，但未在此答案中包含它，因为它不是必需的。这里是：
private static void ExportPublicKey(RSACryptoServiceProvider csp, TextWriter outputStream){ var parameters = csp.ExportParameters(false); using (var stream = new MemoryStream()) { var writer = new BinaryWriter(stream); writer.Write((byte)0x30); // SEQUENCE using (var innerStream = new MemoryStream()) { var innerWriter = new BinaryWriter(innerStream); innerWriter.Write((byte)0x30); // SEQUENCE EnpreLength(innerWriter, 13); innerWriter.Write((byte)0x06); // OBJECT IDENTIFIER var rsaEncryptionOid = new byte[] { 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01 }; EnpreLength(innerWriter, rsaEncryptionOid.Length); innerWriter.Write(rsaEncryptionOid); innerWriter.Write((byte)0x05); // NULL EnpreLength(innerWriter, 0); innerWriter.Write((byte)0x03); // BIT STRING using (var bitStringStream = new MemoryStream()) { var bitStringWriter = new BinaryWriter(bitStringStream); bitStringWriter.Write((byte)0x00); // # of unused bits bitStringWriter.Write((byte)0x30); // SEQUENCE using (var paramsStream = new MemoryStream()) { var paramsWriter = new BinaryWriter(paramsStream); EnpreIntegerBigEndian(paramsWriter, parameters.Modulus); // Modulus EnpreIntegerBigEndian(paramsWriter, parameters.Exponent); // Exponent var paramsLength = (int)paramsStream.Length; EnpreLength(bitStringWriter, paramsLength); bitStringWriter.Write(paramsStream.GetBuffer(), 0, paramsLength); } var bitStringLength = (int)bitStringStream.Length; EnpreLength(innerWriter, bitStringLength); innerWriter.Write(bitStringStream.GetBuffer(), 0, bitStringLength); } var length = (int)innerStream.Length; EnpreLength(writer, length); writer.Write(innerStream.GetBuffer(), 0, length); } var base64 = Convert.Tobase64String(stream.GetBuffer(), 0, (int)stream.Length).ToCharArray(); outputStream.WriteLine("-----BEGIN PUBLIC KEY-----"); for (var i = 0; i < base64.Length; i += 64) { outputStream.WriteLine(base64, i, Math.Min(64, base64.Length - i)); } outputStream.WriteLine("-----END PUBLIC KEY-----"); }}private static void EnpreLength(BinaryWriter stream, int length){ if (length < 0) throw new ArgumentOutOfRangeException("length", "Length must be non-negative"); if (length < 0x80) { // Short form stream.Write((byte)length); } else { // Long form var temp = length; var bytesRequired = 0; while (temp > 0) { temp >>= 8; bytesRequired++; } stream.Write((byte)(bytesRequired | 0x80)); for (var i = bytesRequired - 1; i >= 0; i--) { stream.Write((byte)(length >> (8 * i) & 0xff)); } }}private static void EnpreIntegerBigEndian(BinaryWriter stream, byte[] value, bool forceUnsigned = true){ stream.Write((byte)0x02); // INTEGER var prefixZeros = 0; for (var i = 0; i < value.Length; i++) { if (value[i] != 0) break; prefixZeros++; } if (value.Length - prefixZeros == 0) { EnpreLength(stream, 1); stream.Write((byte)0); } else { if (forceUnsigned && value[prefixZeros] > 0x7f) { // Add a prefix zero to force unsigned if the MSB is 1 EnpreLength(stream, value.Length - prefixZeros + 1); stream.Write((byte)0); } else { EnpreLength(stream, value.Length - prefixZeros); } for (var i = prefixZeros; i < value.Length; i++) { stream.Write(value[i]); } }}
