<PackageReference Include="BouncyCastle.Cryptography" Version="2.3.1" />

PemParser

class PemParser
using Org.BouncyCastle.Asn1; using Org.BouncyCastle.Utilities; using Org.BouncyCastle.Utilities.Encoders; using System.IO; using System.Text; namespace Org.BouncyCastle.X509 { internal class PemParser { private readonly string _header1; private readonly string _header2; private readonly string _footer1; private readonly string _footer2; internal PemParser(string type) { _header1 = "-----BEGIN " + type + "-----"; _header2 = "-----BEGIN X509 " + type + "-----"; _footer1 = "-----END " + type + "-----"; _footer2 = "-----END X509 " + type + "-----"; } private string ReadLine(Stream inStream) { StringBuilder stringBuilder = new StringBuilder(); int num; while (true) { if ((num = inStream.ReadByte()) != 13 && num != 10 && num >= 0) { if (num != 13) stringBuilder.Append((char)num); } else if (num < 0 || stringBuilder.Length != 0) { break; } } if (num < 0) return null; return stringBuilder.ToString(); } internal Asn1Sequence ReadPemObject(Stream inStream) { StringBuilder stringBuilder = new StringBuilder(); string source; while ((source = ReadLine(inStream)) != null && !Platform.StartsWith(source, _header1) && !Platform.StartsWith(source, _header2)) { } while ((source = ReadLine(inStream)) != null && !Platform.StartsWith(source, _footer1) && !Platform.StartsWith(source, _footer2)) { stringBuilder.Append(source); } if (stringBuilder.Length != 0) { Asn1Object asn1Object = Asn1Object.FromByteArray(Base64.Decode(stringBuilder.ToString())); if (!(asn1Object is Asn1Sequence)) throw new IOException("malformed PEM data encountered"); return (Asn1Sequence)asn1Object; } return null; } } }