feat: hinzugefügte Index-Eigenschaft zur IAsymCryptService-Schnittstelle

- Neue Index-Eigenschaft `this[string key]` zur `IAsymCryptService`-Schnittstelle hinzugefügt.
- Ermöglicht das Abrufen spezifischer `IRSADecryptor`-Instanzen anhand eines Schlüsselstrings.
- Schnittstellendefinition aktualisiert, um die Funktionalität für implementierende Klassen zu erweitern.

DigitalData.Core.Abstractions/Security/IAsymCryptService.cs

@@ -3,6 +3,8 @@
     public interface IAsymCryptService : IRSAFactory
     {
         public IEnumerable<IRSADecryptor> Decryptors { get; }
+
+        public IRSADecryptor this[string key] { get; }
     }
 
     public interface IAsymCryptService<TParams> : IAsymCryptService, IRSAFactory<TParams> { }

DigitalData.Core.Abstractions/Security/IRSACryptographer.cs

@@ -11,7 +11,5 @@ namespace DigitalData.Core.Abstractions.Security
         public string Issuer { get; init; }
 
         public string Audience { get; init; }
-
-        public void Init();
     }
 }

DigitalData.Core.Abstractions/Security/IRSADecryptor.cs

@@ -2,7 +2,7 @@
 {
     public interface IRSADecryptor : IRSACryptographer
     {
-        public bool Encrypt { get; init; }
+        public bool IsEncrypted { get; init; }
 
         IRSAEncryptor Encryptor { get; }
 

DigitalData.Core.Abstractions/Security/IRSAFactory.cs

@@ -4,14 +4,19 @@ namespace DigitalData.Core.Abstractions.Security
 {
     public interface IRSAFactory
     {
-        string CreateRSAPrivateKeyPem(int? keySizeInBits = null);
+        string CreatePrivateKeyPem(int? keySizeInBits = null);
 
-        string CreateEncryptedPrivateKeyPem(
-            int? keySizeInBits = null,
-            string? password = null,
+        public string CreateEncryptedPrivateKeyPem(
             PbeEncryptionAlgorithm? pbeEncryptionAlgorithm = null,
             HashAlgorithmName? hashAlgorithmName = null,
-            int? iterationCount = null);
+            int? iterationCount = null,
+            int? keySizeInBits = null,
+            string? password = null);
+
+        public string CreateEncryptedPrivateKeyPem(
+            PbeParameters pbeParameters,
+            int? keySizeInBits = null,
+            string? password = null);
     }
 
     public interface IRSAFactory<TParams> : IRSAFactory { }

DigitalData.Core.Security/AsymCryptService.cs

@@ -3,16 +3,47 @@ using DigitalData.Core.Security.Config;
 using DigitalData.Core.Security.Cryptographer;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
+using System.Collections;
 
 namespace DigitalData.Core.Security
 {
-    public class AsymCryptService<TAsymCryptParams> : RSAFactory<TAsymCryptParams>, IAsymCryptService<TAsymCryptParams>, IRSAFactory<TAsymCryptParams> where TAsymCryptParams : AsymCryptParams
+    public class AsymCryptService<TAsymCryptParams> : RSAFactory<TAsymCryptParams>, IAsymCryptService<TAsymCryptParams>, IRSAFactory<TAsymCryptParams>, IEnumerable<IRSADecryptor>
+        where TAsymCryptParams : AsymCryptParams
     {
         public IEnumerable<IRSADecryptor> Decryptors => _params.Decryptors;
 
+        public IRSADecryptor this[string key]
+        {
+            get
+            {
+                var key_params = key.Split(_params.KeyNameSeparator);
+
+                if (key_params.Length != 2)
+                    throw new ArgumentException($"Invalid key format. Expected two segments separated by '{_params.KeyNameSeparator}', but received: '{key}'.", nameof(key));
+
+                return _params.Decryptors.FirstOrDefault(d => d.Issuer == key_params[0] && d.Audience == key_params[1])
+                    ?? throw new KeyNotFoundException($"No decryptor found matching the issuer '{key_params[0]}' and audience '{key_params[1]}'.");
+            }
+        }
+
         public AsymCryptService(IOptions<TAsymCryptParams> options, ILogger<AsymCryptService<TAsymCryptParams>>? logger = null) : base(options)
         {
             logger?.LogInformation("Core.Secrets version: {Version}, Created on: {CreationDate}.", Secrets.Version, Secrets.CreationDate.ToString("dd.MM.yyyy"));
         }
+
+        public IEnumerator<IRSADecryptor> GetEnumerator() => Decryptors.GetEnumerator();
+
+        IEnumerator IEnumerable.GetEnumerator() => Decryptors.GetEnumerator();
+
+        public IEnumerable<IRSAEncryptor> Encryptors
+        {
+            get
+            {
+                foreach (var decryptor in Decryptors)
+                {
+                    yield return decryptor.Encryptor;
+                }
+            }
+        }
     }
 }

DigitalData.Core.Security/Config/AsymCryptParams.cs

@@ -6,19 +6,35 @@ namespace DigitalData.Core.Security.Config
     {
         public string PemDirectory { get; init; } = string.Empty;
 
-        public string Separator { get; init; } = "_-_";
-
-        public IEnumerable<RSADecryptor> Decryptors { get; init; } = new List<RSADecryptor>();
+        /// <summary>
+        /// Represents the separator used to concatenate the components of a file-related token string.
+        /// </summary>
+        /// <remarks>
+        /// The resulting file-related token string is constructed as follows:
+        /// <c>string.Join(FileNameSeparator, Issuer, Audience, Secret_version)</c>.
+        /// If <c>Secret_version</c> is not null, it will be included in the concatenation.
+        /// </remarks>
+        /// <example>
+        /// For example, if <c>FileNameSeparator = "_-_"</c>, the output might look like:
+        /// <c>"Issuer_-_Audience_-_Secret_version"</c>.
+        /// </example>
+        public string FileNameSeparator { get; init; } = "_-_";
 
         /// <summary>
-        /// 0: Issuer - 1: Audience - 2: Secret version (if is encrypted)
+        /// Represents the separator used to concatenate the components of a key-related token string.
         /// </summary>
-        private string CreateFileName(params object[] objs) => string.Join(Separator, objs);
+        /// <remarks>
+        /// The resulting key-related token string is constructed as follows:
+        /// <c>string.Join(KeyNameSeparator, Issuer, Audience, Secret_version)</c>.
+        /// If <c>Secret_version</c> is not null, it will be included in the concatenation.
+        /// </remarks>
+        /// <example>
+        /// For example, if <c>KeyNameSeparator = ":"</c>, the output might look like:
+        /// <c>"Issuer:Audience:Secret_version"</c>.
+        /// </example>
+        public string KeyNameSeparator { get; init; } = ":";
 
-        private string CreatePem(bool isEncrypted) => isEncrypted
-            ? Instance.RSAFactory.CreateEncryptedPrivateKeyPem(keySizeInBits: KeySizeInBits, password: Secrets.PBE_PASSWORD,
-                pbeEncryptionAlgorithm: PbeEncryptionAlgorithm, hashAlgorithmName: PbeHashAlgorithmName, iterationCount: PbeIterationCount)
-            : Instance.RSAFactory.CreateRSAPrivateKeyPem(keySizeInBits: KeySizeInBits);
+        public IEnumerable<RSADecryptor> Decryptors { get; init; } = new List<RSADecryptor>();
 
         public override void OnDeserialized()
         {
@@ -28,29 +44,33 @@ namespace DigitalData.Core.Security.Config
             if (!Directory.Exists(PemDirectory))
                 Directory.CreateDirectory(PemDirectory);
 
-            foreach (var crypt in Decryptors)
+            foreach (var decryptor in Decryptors)
             {
                 // set default path
-                if (crypt.IsPemNull)
+                if (decryptor.IsPemNull)
                 {
-                    var file_name_params = new List<object> { crypt.Issuer, crypt.Audience };
-                    if (crypt.Encrypt)
+                    var file_name_params = new List<object> { decryptor.Issuer, decryptor.Audience };
+                    if (decryptor.IsEncrypted)
                         file_name_params.Add(Secrets.Version);
 
-                    var file_name = CreateFileName(file_name_params);
-                    var path = Path.Combine(PemDirectory, file_name);
+                    var path = Path.Combine(PemDirectory, string.Join(FileNameSeparator, file_name_params));
 
                     if (File.Exists(path))
-                        crypt.SetPem(File.ReadAllText(path));
+                        decryptor.SetPem(File.ReadAllText(path));
                     else
                     {
-                        var pem = CreatePem(crypt.Encrypt);
-                        crypt.SetPem(File.ReadAllText(pem));
+                        var pem = decryptor.IsEncrypted
+                            ? Instance.RSAFactory.CreateEncryptedPrivateKeyPem(pbeParameters: PbeParameters, keySizeInBits: KeySizeInBits, password: Secrets.PBE_PASSWORD)
+                            : Instance.RSAFactory.CreatePrivateKeyPem(keySizeInBits: KeySizeInBits);
+
+                        decryptor.SetPem(File.ReadAllText(pem));
+
+                        // Save file in background
                         Task.Run(async () => await File.WriteAllTextAsync(path: path, pem));
                     }
                 }
 
-                crypt.Init();
+                decryptor.Init();
             }
         }
     }

DigitalData.Core.Security/Cryptographer/RSACryptographer.cs

@@ -5,19 +5,8 @@ namespace DigitalData.Core.Security.Cryptographer
 {
     public class RSACryptographer : IRSACryptographer
     {
-        protected string? _pem;
-
-        public string Pem
-        {
-            get => _pem
-                ?? throw PemIsNullException;
-            init => _pem = value;
-        }
-
-        internal bool IsPemNull => _pem is null;
-        
-        private InvalidOperationException PemIsNullException => new($"Pem is not initialized. Please ensure that the PEM is set or properly loaded from the file. Issuer: {Issuer}, Audience: {Audience}.");
-        
+        public virtual string Pem { get; init; }
+                
         public RSAEncryptionPadding Padding { get; init; } = RSAEncryptionPadding.OaepSHA256;
 
         protected virtual RSA RSA { get; } = RSA.Create();
@@ -26,14 +15,8 @@ namespace DigitalData.Core.Security.Cryptographer
 
         public string Audience { get; init; } = string.Empty;
 
+#pragma warning disable CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.
         internal RSACryptographer() { }
-
-        internal void SetPem(string pem) => _pem = pem;
-
-        public virtual void Init()
-        {
-            if (_pem is null)
-                throw PemIsNullException;
-        }
+#pragma warning restore CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.
     }
 }

DigitalData.Core.Security/Cryptographer/RSADecryptor.cs

@@ -6,7 +6,13 @@ namespace DigitalData.Core.Security.Cryptographer
 {
     public class RSADecryptor : RSACryptographer, IRSADecryptor, IRSACryptographer
     {
-        public bool Encrypt { get; init; }
+        private string? _pem;
+
+        public override string Pem { get => _pem ?? throw PemIsNullException; init => _pem = value; }
+
+        public bool IsPemNull => _pem is null;
+
+        public bool IsEncrypted { get; init; }
 
         private readonly Lazy<IRSAEncryptor> _lazyEncryptor;
 
@@ -25,13 +31,19 @@ namespace DigitalData.Core.Security.Cryptographer
 
         public string Decrypt(string data) => RSA.Decrypt(data.Base64ToByte(), Padding).BytesToString();
 
-        public override void Init()
+        internal void SetPem(string pem) => _pem = pem;
+
+        public void Init()
         {
-            base.Init();
-            if (Encrypt)
+            if (_pem is null)
+                throw PemIsNullException;
+
+            if (IsEncrypted)
                 RSA.ImportFromEncryptedPem(Pem, Secrets.PBE_PASSWORD.AsSpan());
             else
                 RSA.ImportFromPem(Pem);
         }
+
+        private InvalidOperationException PemIsNullException => new($"Pem is not initialized. Please ensure that the PEM is set or properly loaded from the file. Issuer: {Issuer}, Audience: {Audience}.");
     }
 }

DigitalData.Core.Security/Cryptographer/RSAEncryptor.cs

@@ -4,17 +4,21 @@ using DigitalData.Core.Security.Extensions;
 namespace DigitalData.Core.Security.Cryptographer
 {
     public class RSAEncryptor : RSACryptographer, IRSAEncryptor, IRSACryptographer
-    {   
+    {
+        public override string Pem 
+        {
+            get => base.Pem;
+            init
+            {
+                base.Pem = value;
+                RSA.ImportFromPem(value);
+            }
+        }
+
         public byte[] Encrypt(byte[] data) => RSA.Encrypt(data, Padding);
 
         public string Encrypt(string data) => RSA.Encrypt(data.Base64ToByte(), Padding).BytesToString();
 
         public bool Verify(string data, string signature) => Encrypt(data) == signature;
-
-        public override void Init()
-        {
-            base.Init();
-            RSA.ImportFromPem(base.Pem);
-        }
     }
 }

DigitalData.Core.Security/Cryptographer/RSAFactory.cs

@@ -11,15 +11,15 @@ namespace DigitalData.Core.Security.Cryptographer
 
         public RSAFactory(IOptions<TRSAFactoryParams> options) => _params = options.Value;
 
-        public string CreateRSAPrivateKeyPem(int? keySizeInBits = null)
+        public string CreatePrivateKeyPem(int? keySizeInBits = null)
             => RSA.Create(keySizeInBits ?? _params.KeySizeInBits).ExportRSAPrivateKeyPem();
 
         public string CreateEncryptedPrivateKeyPem(
-            int? keySizeInBits = null,
-            string? password = null,
             PbeEncryptionAlgorithm? pbeEncryptionAlgorithm = null,
             HashAlgorithmName? hashAlgorithmName = null,
-            int? iterationCount = null)
+            int? iterationCount = null,
+            int? keySizeInBits = null,
+            string? password = null)
         {
             password ??= _params.PbePassword;
 
@@ -36,5 +36,19 @@ namespace DigitalData.Core.Security.Cryptographer
 
             return new string(pemChars);
         }
+
+        public string CreateEncryptedPrivateKeyPem(
+            PbeParameters pbeParameters,
+            int? keySizeInBits = null,
+            string? password = null)
+        {
+            password ??= _params.PbePassword;
+
+            var encryptedPrivateKey = RSA.Create(keySizeInBits ?? _params.KeySizeInBits).ExportEncryptedPkcs8PrivateKey(password.AsSpan(), pbeParameters);
+
+            var pemChars = PemEncoding.Write(_params.EncryptedPrivateKeyPemLabel, encryptedPrivateKey);
+
+            return new string(pemChars);
+        }
     }
 }