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Lec6(Practical) Computer Security

Lec6(Practical) Computer Security. Encryption التشفير. خوارزمية DES. DES (Data Encryption Standard) AES (Advanced Encryption Standard) هي النسخة التالية لـ ( DES ) البرنامجين التاليين يستخدمان الدوال الخاصة بخوارزمية DES والموجودة في VB.NET

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Lec6(Practical) Computer Security

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  1. Lec6(Practical)Computer Security Encryption التشفير

  2. خوارزمية DES • DES (Data Encryption Standard) • AES (Advanced Encryption Standard)هي النسخة التالية لـ (DES) • البرنامجين التاليين يستخدمان الدوال الخاصة بخوارزمية DES والموجودة في VB.NET • البرنامج الأول يقوم بعملية التشفير للملف file1_plaintext.txt في ملف جديد file2_encryptedtext.txt

  3. خوارزمية DES • البرنامج الثاني يقوم بعملية فك التشفير من على الملف file2_encryptedtext.txt في ملف جديد file3_decryptedtext.txt

  4. خوارزمية DES(البرنامج الأول) Imports System.Security.Cryptography Imports Microsoft Module Module1 Sub Main() Dim sourcefile As String = "f:\\ file1_plaintext.txt " Dim destfile As String = "f:\\ file2_encryptedtext.txt " Dim deskey As Byte() = {100, 55, 6, 24, 86, 206, 90, 176} Dim desiv As Byte() = {45, 76, 45, 97, 243, 68, 101, 76} Dim fin As New System.IO.FileStream(sourcefile, IO.FileMode.Open, IO.FileAccess.Read) Dim fout As New System.IO.FileStream(destfile, IO.FileMode.OpenOrCreate, IO.FileAccess.Write) Dim bin(4096) As Byte Dim rdlen As Long = 0 Dim totlen As Long = fin.Length Dim len As Integer

  5. خوارزمية DES(البرنامج الأول) Dim des As New DESCryptoServiceProvider() Dim decSstrem As New CryptoStream(fout, des.CreateEncryptor(deskey, desiv), CryptoStreamMode.Write) While rdlen < totlen len = fin.Read(bin, 0, 4096) MsgBox(len) decSstrem.Write(bin, 0, len) rdlen = Convert.ToInt32(rdlen + len / des.BlockSize * des.BlockSize) End While decSstrem.Close() fout.Close() fin.Close() End Sub End Module

  6. خوارزمية AES(البرنامج الثاني) Imports System.Security.Cryptography Module Module1 Sub Main() Dim sourcefile As String = "f:\\ file2_encryptedtext.txt " Dim destfile As String = "f:\\ file3_decryptedtext.txt " Dim deskey As Byte() = {100, 55, 6, 24, 86, 206, 90, 176} Dim desiv As Byte() = {45, 76, 45, 97, 243, 68, 101, 76} Dim fin As New System.IO.FileStream(sourcefile, IO.FileMode.Open, IO.FileAccess.Read) Dim fout As New System.IO.FileStream(destfile, IO.FileMode.OpenOrCreate, IO.FileAccess.Write) Dim bin(4096) As Byte Dim rdlen As Long = 0 Dim totlen As Long = fin.Length Dim len As Integer

  7. خوارزمية AES(البرنامج الثاني) Dim des As New DESCryptoServiceProvider() Dim decSstrem As New CryptoStream(fout, des.CreateDecryptor(deskey, desiv), CryptoStreamMode.Write) While rdlen < totlen len = fin.Read(bin, 0, 4096) MsgBox(len) decSstrem.Write(bin, 0, len) rdlen = Convert.ToInt32(rdlen + len / des.BlockSize * des.BlockSize) End While decSstrem.Close() fout.Close() fin.Close() End Sub End Module

  8. خوارزمية DES • قومي بإنشاء الملف الأول file1_plaintext.txt وأدخلي فيه أي نص • قومي بتنفيذ البرنامج الأول لإنشاء الملف المشفر file2_encryptedtext.txt • ومن ثم قومي بتنفيذ البرنامج الثاني لإنشاء الملف غير المشفر file3_decryptedtext.txt

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