Error on encryption/decryption files
When I decrypt an encrypted file; it doesn't have the same size in bytes as the original file and the the hash of the file is different.
I get the bytes of the file using File.ReadAllBytes and send to EncryptBytes with the password. Also the same with DecryptBytes.
When I receive the bytes encrypted or decrypted i save them using File.WriteAllBytes.
I need that the decrypted file and original file have the same hash an bytes.
Please help
This my code:
Public Function EncryptBytes(ByVal pass As String, ByVal bytes() As Byte)
Dim myRijndael As New RijndaelManaged
myRijndael.Padding = PaddingMode.Zeros
myRijndael.KeySize = 256
myRijndael.BlockSize = 256
Dim encrypted() As Byte
Dim key() As Byte = CreateKey(pass)
Dim IV() As Byte = CreateIV(pass)
Dim encryptor As ICryptoTransform = myRijndael.CreateEncryptor(key, IV)
Dim msEncrypt As New MemoryStream()
Dim csEncrypt As New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)
csEncrypt.Write(bytes, 0, bytes.开发者_开发百科Length)
csEncrypt.FlushFinalBlock()
encrypted = msEncrypt.ToArray()
Return encrypted
End Function
Public Function DecryptBytes(ByVal pass As String, ByVal bytes() As Byte)
Dim myRijndael As New RijndaelManaged
myRijndael.Padding = PaddingMode.Zeros
myRijndael.KeySize = 256
myRijndael.BlockSize = 256
Dim key() As Byte = CreateKey(pass)
Dim IV() As Byte = CreateIV(pass)
Dim decryptor As ICryptoTransform = myRijndael.CreateDecryptor(key, IV)
Dim fromEncrypt() As Byte = New Byte(bytes.Length) {}
Dim msDecrypt As New MemoryStream(bytes)
Dim csDecrypt As New CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)
csDecrypt.Read(fromEncrypt, 0, fromEncrypt.Length)
Return fromEncrypt
End Function
Private Function CreateKey(ByVal strPassword As String) As Byte()
Dim chrData() As Char = strPassword.ToCharArray
Dim intLength As Integer = chrData.GetUpperBound(0)
Dim bytDataToHash(intLength) As Byte
For i As Integer = 0 To chrData.GetUpperBound(0)
bytDataToHash(i) = CByte(Asc(chrData(i)))
Next
Dim SHA512 As New System.Security.Cryptography.SHA512Managed
Dim bytResult As Byte() = SHA512.ComputeHash(bytDataToHash)
Dim bytKey(31) As Byte
For i As Integer = 0 To 31
bytKey(i) = bytResult(i)
Next
Return bytKey
End Function
Private Function CreateIV(ByVal strPassword As String) As Byte()
Dim chrData() As Char = strPassword.ToCharArray
Dim intLength As Integer = chrData.GetUpperBound(0)
Dim bytDataToHash(intLength) As Byte
For i As Integer = 0 To chrData.GetUpperBound(0)
bytDataToHash(i) = CByte(Asc(chrData(i)))
Next
Dim SHA512 As New System.Security.Cryptography.SHA512Managed
Dim bytResult As Byte() = SHA512.ComputeHash(bytDataToHash)
Dim bytIV(31) As Byte
For i As Integer = 32 To 47
bytIV(i - 32) = bytResult(i)
Next
Return bytIV
End Function
Your DecryptBytes() method is broken. You are not using the return value of csDecrypt.Read(), it tells you have many bytes were decrypted. That will not be the same as fromEncrypt.Length. You'd also have a very hard time guessing how large a byte array to pass to this function.
Consider changing the function to return a MemoryStream. Call Read() in a loop and write what was read to the memory stream. Exit the loop when Read() returns 0.
Try this:
Public Function EncryptBytes(ByVal pass As String, ByVal bytes() As Byte)
Dim myRijndael As New RijndaelManaged
myRijndael.Padding = PaddingMode.PKCS7
myRijndael.Mode = CipherMode.CBC
myRijndael.KeySize = 256
myRijndael.BlockSize = 256
Dim encrypted() As Byte
Dim key() As Byte = CreateKey(pass)
Dim IV() As Byte = CreateIV(pass)
Dim encryptor As ICryptoTransform = myRijndael.CreateEncryptor(key, IV)
Dim msEncrypt As New MemoryStream()
Dim csEncrypt As New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)
csEncrypt.Write(bytes, 0, bytes.Length)
csEncrypt.FlushFinalBlock()
encrypted = msEncrypt.ToArray()
Return encrypted
msEncrypt.Close()
csEncrypt.Close()
End Function
Public Function DecryptBytes(ByVal pass As String, ByVal bytes() As Byte)
Dim myRijndael As New RijndaelManaged
myRijndael.Padding = PaddingMode.PKCS7
myRijndael.Mode = CipherMode.CBC
myRijndael.KeySize = 256
myRijndael.BlockSize = 256
Dim decrypted() As Byte
Dim key() As Byte = CreateKey(pass)
Dim IV() As Byte = CreateIV(pass)
Dim decryptor As ICryptoTransform = myRijndael.CreateDecryptor(key, IV)
Dim msDecrypt As New MemoryStream()
Dim csDecrypt As New CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Write)
csDecrypt.Write(bytes, 0, bytes.Length)
csDecrypt.FlushFinalBlock()
decrypted = msDecrypt.ToArray()
Return decrypted
msDecrypt.Close()
csDecrypt.Close()
End Function
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