September Morn Update

Task/RSA-code/Visual-Basic-.NET/rsa-code.visual

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+Imports System
+Imports System.Numerics
+Imports System.Text
+
+Module Module1
+    Sub Main()
+        Dim n As BigInteger = BigInteger.Parse("9516311845790656153499716760847001433441357")
+        Dim e As BigInteger = 65537
+        Dim d As BigInteger = BigInteger.Parse("5617843187844953170308463622230283376298685")
+        Dim plainTextStr As String = "Hello, Rosetta!"
+        Dim plainTextBA As Byte() = ASCIIEncoding.ASCII.GetBytes(plainTextStr)
+        Dim pt As BigInteger = New BigInteger(plainTextBA)
+        If pt > n Then Throw New Exception() ' Blocking not implemented
+        Dim ct As BigInteger = BigInteger.ModPow(pt, e, n)
+        Console.WriteLine(" Encoded: " & ct.ToString("X"))
+        Dim dc As BigInteger = BigInteger.ModPow(ct, d, n)
+        Console.WriteLine(" Decoded: " & dc.ToString("X"))
+        Dim decoded As String = ASCIIEncoding.ASCII.GetString(dc.ToByteArray())
+        Console.WriteLine("As ASCII: " & decoded)
+    End Sub
+End Module