dsa.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Security / Cryptography / dsa.cs / 1 / dsa.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 

// 
// DSA.cs 
//
 
namespace System.Security.Cryptography {
    using System.Text;
    using System.Runtime.Serialization;
    using System.Security.Util; 
    using System.Globalization;
 
    // DSAParameters is serializable so that one could pass the public parameters 
    // across a remote call, but we explicitly make the private key X non-serializable
    // so you cannot accidently send it along with the public parameters. 
    [Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
    public struct DSAParameters {
        public byte[]      P; 
        public byte[]      Q;
        public byte[]      G; 
        public byte[]      Y; 
        public byte[]      J;
        [NonSerialized] public byte[]      X; 
        public byte[]      Seed;
        public int         Counter;
    }
 
[System.Runtime.InteropServices.ComVisible(true)]
    public abstract class DSA : AsymmetricAlgorithm 
    { 
        //
        //  Extending this class allows us to know that you are really implementing 
        //  an DSA key.  This is required for anybody providing a new DSA key value
        //  implemention.
        //
        //  The class provides no methods, fields or anything else.  Its only purpose is 
        //  as a heirarchy member for identification of the algorithm.
        // 
 
        protected DSA() { }
 
        //
        // public methods
        //
 
        new static public DSA Create() {
            return Create("System.Security.Cryptography.DSA"); 
        } 

        new static public DSA Create(String algName) { 
            return (DSA) CryptoConfig.CreateFromName(algName);
        }

        abstract public byte[] CreateSignature(byte[] rgbHash); 

        abstract public bool VerifySignature(byte[] rgbHash, byte[] rgbSignature); 
 
        // We can provide a default implementation of FromXmlString because we require
        // every DSA implementation to implement ImportParameters 
        // All we have to do here is parse the XML.

        public override void FromXmlString(String xmlString) {
            if (xmlString == null) throw new ArgumentNullException("xmlString"); 
            DSAParameters dsaParams = new DSAParameters();
            Parser p = new Parser(xmlString); 
            SecurityElement topElement = p.GetTopElement(); 

            // P is always present 
            String pString = topElement.SearchForTextOfLocalName("P");
            if (pString == null) {
                throw new CryptographicException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Cryptography_InvalidFromXmlString"),"DSA","P"));
            } 
            dsaParams.P = Convert.FromBase64String(Utils.DiscardWhiteSpaces(pString));
 
            // Q is always present 
            String qString = topElement.SearchForTextOfLocalName("Q");
            if (qString == null) { 
                throw new CryptographicException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Cryptography_InvalidFromXmlString"),"DSA","Q"));
            }
            dsaParams.Q = Convert.FromBase64String(Utils.DiscardWhiteSpaces(qString));
 
            // G is always present
            String gString = topElement.SearchForTextOfLocalName("G"); 
            if (gString == null) { 
                throw new CryptographicException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Cryptography_InvalidFromXmlString"),"DSA","G"));
            } 
            dsaParams.G = Convert.FromBase64String(Utils.DiscardWhiteSpaces(gString));

            // Y is always present
            String yString = topElement.SearchForTextOfLocalName("Y"); 
            if (yString == null) {
                throw new CryptographicException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Cryptography_InvalidFromXmlString"),"DSA","Y")); 
            } 
            dsaParams.Y = Convert.FromBase64String(Utils.DiscardWhiteSpaces(yString));
 
            // J is optional
            String jString = topElement.SearchForTextOfLocalName("J");
            if (jString != null) dsaParams.J = Convert.FromBase64String(Utils.DiscardWhiteSpaces(jString));
 
            // X is optional -- private key if present
            String xString = topElement.SearchForTextOfLocalName("X"); 
            if (xString != null) dsaParams.X = Convert.FromBase64String(Utils.DiscardWhiteSpaces(xString)); 

            // Seed and PgenCounter are optional as a unit -- both present or both absent 
            String seedString = topElement.SearchForTextOfLocalName("Seed");
            String pgenCounterString = topElement.SearchForTextOfLocalName("PgenCounter");
            if ((seedString != null) && (pgenCounterString != null)) {
                dsaParams.Seed = Convert.FromBase64String(Utils.DiscardWhiteSpaces(seedString)); 
                dsaParams.Counter = Utils.ConvertByteArrayToInt(Convert.FromBase64String(Utils.DiscardWhiteSpaces(pgenCounterString)));
            } else if ((seedString != null) || (pgenCounterString != null)) { 
                if (seedString == null) { 
                    throw new CryptographicException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Cryptography_InvalidFromXmlString"),"DSA","Seed"));
                } else { 
                    throw new CryptographicException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Cryptography_InvalidFromXmlString"),"DSA","PgenCounter"));
                }
            }
 
            ImportParameters(dsaParams);
        } 
 
        // We can provide a default implementation of ToXmlString because we require
        // every DSA implementation to implement ImportParameters 
        // If includePrivateParameters is false, this is just an XMLDSIG DSAKeyValue
        // clause.  If includePrivateParameters is true, then we extend DSAKeyValue with
        // the other (private) elements.
 
        public override String ToXmlString(bool includePrivateParameters) {
            // From the XMLDSIG spec, RFC 3075, Section 6.4.1, a DSAKeyValue looks like this: 
            /* 
               
                  
                   
                     
                       
                        
                       
                        
                        
                     
                      
                       
                       
                     
                    
                 
                
            */ 
            // we extend appropriately for private component X
            DSAParameters dsaParams = this.ExportParameters(includePrivateParameters); 
            StringBuilder sb = new StringBuilder();
            sb.Append("");
            // Add P, Q, G and Y
            sb.Append("
"+Convert.ToBase64String(dsaParams.P)+"
"); 
            sb.Append(""+Convert.ToBase64String(dsaParams.Q)+"");
            sb.Append(""+Convert.ToBase64String(dsaParams.G)+""); 
            sb.Append(""+Convert.ToBase64String(dsaParams.Y)+""); 
            // Add optional components if present
            if (dsaParams.J != null) { 
                sb.Append(""+Convert.ToBase64String(dsaParams.J)+"");
            }
            if ((dsaParams.Seed != null)) {  // note we assume counter is correct if Seed is present
                sb.Append(""+Convert.ToBase64String(dsaParams.Seed)+""); 
                sb.Append(""+Convert.ToBase64String(Utils.ConvertIntToByteArray(dsaParams.Counter))+"");
            } 
 
            if (includePrivateParameters) {
                // Add the private component 
                sb.Append(""+Convert.ToBase64String(dsaParams.X)+"");
            }
            sb.Append("");
            return(sb.ToString()); 
        }
 
        abstract public DSAParameters ExportParameters(bool includePrivateParameters); 

        abstract public void ImportParameters(DSAParameters parameters); 
    }
}

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