3 // Copyright (c) Microsoft Corporation. All rights reserved.
6 // <OWNER>Microsoft</OWNER>
10 // RSAPKCS1SignatureFormatter.cs
14 using System.Diagnostics.Contracts;
15 using System.Security.Cryptography.X509Certificates;
17 namespace System.Security.Cryptography {
18 [System.Runtime.InteropServices.ComVisible(true)]
19 public class RSAPKCS1SignatureFormatter : AsymmetricSignatureFormatter {
21 private String _strOID;
22 private bool? _rsaOverridesSignHash;
25 // public constructors
28 public RSAPKCS1SignatureFormatter() {}
30 public RSAPKCS1SignatureFormatter(AsymmetricAlgorithm key) {
32 throw new ArgumentNullException("key");
33 Contract.EndContractBlock();
41 public override void SetKey(AsymmetricAlgorithm key) {
43 throw new ArgumentNullException("key");
44 Contract.EndContractBlock();
46 _rsaOverridesSignHash = default(bool?);
49 public override void SetHashAlgorithm(String strName) {
50 _strOID = CryptoConfig.MapNameToOID(strName, OidGroup.HashAlgorithm);
53 [System.Security.SecuritySafeCritical] // auto-generated
54 public override byte[] CreateSignature(byte[] rgbHash) {
56 throw new ArgumentNullException("rgbHash");
57 Contract.EndContractBlock();
60 throw new CryptographicUnexpectedOperationException(Environment.GetResourceString("Cryptography_MissingOID"));
62 throw new CryptographicUnexpectedOperationException(Environment.GetResourceString("Cryptography_MissingKey"));
64 // Two cases here -- if we are talking to the CSP version or if we are talking to some other RSA provider.
65 if (_rsaKey is RSACryptoServiceProvider) {
66 // This path is kept around for desktop compat: in case someone is using this with a hash algorithm that's known to GetAlgIdFromOid but
67 // not from OidToHashAlgorithmName.
68 int calgHash = X509Utils.GetAlgIdFromOid(_strOID, OidGroup.HashAlgorithm);
69 return ((RSACryptoServiceProvider)_rsaKey).SignHash(rgbHash, calgHash);
71 else if (OverridesSignHash) {
72 HashAlgorithmName hashAlgorithmName = Utils.OidToHashAlgorithmName(_strOID);
73 return _rsaKey.SignHash(rgbHash, hashAlgorithmName, RSASignaturePadding.Pkcs1);
76 // Fallback compat path for 3rd-party RSA classes that don't override SignHash()
78 byte[] pad = Utils.RsaPkcs1Padding(_rsaKey, CryptoConfig.EncodeOID(_strOID), rgbHash);
79 // Create the signature by applying the private key to the padded buffer we just created.
80 return _rsaKey.DecryptValue(pad);
84 private bool OverridesSignHash {
86 if (!_rsaOverridesSignHash.HasValue) {
87 _rsaOverridesSignHash = Utils.DoesRsaKeyOverride(_rsaKey, "SignHash", new Type[] { typeof(byte[]), typeof(HashAlgorithmName), typeof(RSASignaturePadding) });
89 return _rsaOverridesSignHash.Value;