Moved RSA+Cipher to separate file. Added RSAEncryptionVariant enum for future support of various encryption / decryption types.

Sources/CryptoSwift/RSA+Cipher.swift

@@ -0,0 +1,65 @@
+//
+//  RSA+Cipher.swift
+//
+//
+//  Created by Brandon Toms on 7/7/22.
+//
+
+import Foundation
+
+// MARK: Cipher
+
+extension RSA: Cipher {
+
+  public enum RSAEncryptionVariant {
+    case raw
+    /// https://datatracker.ietf.org/doc/html/rfc2313#section-8.1
+    // case pksc1v15
+
+    @inlinable func prepare(_ bytes: Array<UInt8>, blockSize: Int) -> Array<UInt8> {
+      switch self {
+        case .raw:
+          return bytes
+//      case .pksc1v15:
+      }
+    }
+
+    @inlinable func removePadding(_ bytes: Array<UInt8>, blockSize: Int) -> Array<UInt8> {
+      switch self {
+        case .raw:
+          return bytes
+//      case .pksc1v15:
+      }
+    }
+  }
+
+  @inlinable
+  public func encrypt(_ bytes: ArraySlice<UInt8>) throws -> Array<UInt8> {
+    // Calculate encrypted data
+    return BigUInteger(Data(bytes)).power(self.e, modulus: self.n).serialize().bytes
+  }
+
+  @inlinable
+  public func encrypt(_ bytes: Array<UInt8>, variant: RSAEncryptionVariant) throws -> Array<UInt8> {
+    // prep the data for the specified variant
+    return try self.encrypt(variant.prepare(bytes, blockSize: self.keySize))
+  }
+
+  @inlinable
+  public func decrypt(_ bytes: ArraySlice<UInt8>) throws -> Array<UInt8> {
+    // Check for Private Exponent presence
+    guard let d = d else {
+      throw RSA.Error.noPrivateKey
+    }
+
+    // Calculate decrypted data
+    return BigUInteger(Data(bytes)).power(d, modulus: self.n).serialize().bytes
+  }
+
+  public func decrypt(_ bytes: Array<UInt8>, variant: RSAEncryptionVariant) throws -> Array<UInt8> {
+    // prep the data for the specified variant
+    let decrypted = try self.decrypt(bytes)
+
+    return variant.removePadding(decrypted, blockSize: self.keySize)
+  }
+}