// // ASN1Convert.cs: Abstract Syntax Notation 1 convertion routines // // Authors: // Sebastien Pouliot // Jesper Pedersen // // (C) 2003 Motus Technologies Inc. (http://www.motus.com) // (C) 2004 IT+ A/S (http://www.itplus.dk) // Copyright (C) 2004-2007 Novell, Inc (http://www.novell.com) // // Permission is hereby granted, free of charge, to any person obtaining // a copy of this software and associated documentation files (the // "Software"), to deal in the Software without restriction, including // without limitation the rights to use, copy, modify, merge, publish, // distribute, sublicense, and/or sell copies of the Software, and to // permit persons to whom the Software is furnished to do so, subject to // the following conditions: // // The above copyright notice and this permission notice shall be // included in all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. // using System; using System.Globalization; using System.Security.Cryptography; using System.Text; namespace Emby.Server.Core.Cryptography { // References: // a. ITU ASN.1 standards (free download) // http://www.itu.int/ITU-T/studygroups/com17/languages/ public static class ASN1Convert { // RFC3280, section 4.2.1.5 // CAs conforming to this profile MUST always encode certificate // validity dates through the year 2049 as UTCTime; certificate validity // dates in 2050 or later MUST be encoded as GeneralizedTime. // Under 1.x this API requires a Local datetime to be provided // Under 2.0 it will also accept a Utc datetime static public ASN1 FromDateTime (DateTime dt) { if (dt.Year < 2050) { // UTCTIME return new ASN1 (0x17, Encoding.ASCII.GetBytes ( dt.ToUniversalTime ().ToString ("yyMMddHHmmss", CultureInfo.InvariantCulture) + "Z")); } else { // GENERALIZEDTIME return new ASN1 (0x18, Encoding.ASCII.GetBytes ( dt.ToUniversalTime ().ToString ("yyyyMMddHHmmss", CultureInfo.InvariantCulture) + "Z")); } } static public ASN1 FromInt32 (Int32 value) { byte[] integer = BitConverterLE.GetBytes (value); Array.Reverse (integer); int x = 0; while ((x < integer.Length) && (integer [x] == 0x00)) x++; ASN1 asn1 = new ASN1 (0x02); switch (x) { case 0: asn1.Value = integer; break; case 4: asn1.Value = new byte [1]; break; default: byte[] smallerInt = new byte [4 - x]; Buffer.BlockCopy (integer, x, smallerInt, 0, smallerInt.Length); asn1.Value = smallerInt; break; } return asn1; } static public ASN1 FromOid (string oid) { if (oid == null) throw new ArgumentNullException ("oid"); return new ASN1 (CryptoConfig.EncodeOID (oid)); } static public ASN1 FromUnsignedBigInteger (byte[] big) { if (big == null) throw new ArgumentNullException ("big"); // check for numbers that could be interpreted as negative (first bit) if (big [0] >= 0x80) { // in thie cas we add a new, empty, byte (position 0) so we're // sure this will always be interpreted an unsigned integer. // However we can't feed it into RSAParameters or DSAParameters int length = big.Length + 1; byte[] uinteger = new byte [length]; Buffer.BlockCopy (big, 0, uinteger, 1, length - 1); big = uinteger; } return new ASN1 (0x02, big); } static public int ToInt32 (ASN1 asn1) { if (asn1 == null) throw new ArgumentNullException ("asn1"); if (asn1.Tag != 0x02) throw new FormatException ("Only integer can be converted"); int x = 0; for (int i=0; i < asn1.Value.Length; i++) x = (x << 8) + asn1.Value [i]; return x; } // Convert a binary encoded OID to human readable string representation of // an OID (IETF style). Based on DUMPASN1.C from Peter Gutmann. static public string ToOid (ASN1 asn1) { if (asn1 == null) throw new ArgumentNullException ("asn1"); byte[] aOID = asn1.Value; StringBuilder sb = new StringBuilder (); // Pick apart the OID byte x = (byte) (aOID[0] / 40); byte y = (byte) (aOID[0] % 40); if (x > 2) { // Handle special case for large y if x = 2 y += (byte) ((x - 2) * 40); x = 2; } sb.Append (x.ToString (CultureInfo.InvariantCulture)); sb.Append ("."); sb.Append (y.ToString (CultureInfo.InvariantCulture)); ulong val = 0; for (x = 1; x < aOID.Length; x++) { val = ((val << 7) | ((byte) (aOID [x] & 0x7F))); if ( !((aOID [x] & 0x80) == 0x80)) { sb.Append ("."); sb.Append (val.ToString (CultureInfo.InvariantCulture)); val = 0; } } return sb.ToString (); } static public DateTime ToDateTime (ASN1 time) { if (time == null) throw new ArgumentNullException ("time"); string t = Encoding.ASCII.GetString (time.Value); // to support both UTCTime and GeneralizedTime (and not so common format) string mask = null; int year; switch (t.Length) { case 11: // illegal format, still it's supported for compatibility mask = "yyMMddHHmmZ"; break; case 13: // RFC3280: 4.1.2.5.1 UTCTime year = Convert.ToInt16 (t.Substring (0, 2), CultureInfo.InvariantCulture); // Where YY is greater than or equal to 50, the // year SHALL be interpreted as 19YY; and // Where YY is less than 50, the year SHALL be // interpreted as 20YY. if (year >= 50) t = "19" + t; else t = "20" + t; mask = "yyyyMMddHHmmssZ"; break; case 15: mask = "yyyyMMddHHmmssZ"; // GeneralizedTime break; case 17: // another illegal format (990630000000+1000), again supported for compatibility year = Convert.ToInt16 (t.Substring (0, 2), CultureInfo.InvariantCulture); string century = (year >= 50) ? "19" : "20"; // ASN.1 (see ITU X.680 section 43.3) deals with offset differently than .NET char sign = (t[12] == '+') ? '-' : '+'; t = String.Format ("{0}{1}{2}{3}{4}:{5}{6}", century, t.Substring (0, 12), sign, t[13], t[14], t[15], t[16]); mask = "yyyyMMddHHmmsszzz"; break; } return DateTime.ParseExact (t, mask, CultureInfo.InvariantCulture, DateTimeStyles.AdjustToUniversal); } } }