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Encrypting a string and the Euro € character

I've inherited some code part of which is to encrypt a string, and then it is saved to a file. See below.

The problem is that when the EURO € (and I presume some other characters) are included in string the are changed to a question mark ?

DES.Key = MD5.ComputeHash(System.Text.ASCIIEncoding.ASCII.GetBytes(key))
DES.Mode = CipherMode.ECB
Dim DESEncrypt As ICryptoTransform = DES.CreateEncryptor()
Dim Buffer As Byte() = System.Text.ASCIIEncoding.ASCII.GetBytes(stringToEncrypt)
Return Convert.ToBase64String(DESEncrypt.TransformFinalBlock(Buffer, 0, Buffer.Length))

I'd appreciate help on this as to how to avoid problem. The fundamental of code can't really change as there are files already saved using this method

Thanks in advance

wdosanjos

The problem with the System.Text.ASCIIEncoding.ASCII.GetBytes(), because the EURO € is not defined in the ASCII encoding. You should use System.Text.Encoding.UTF8.GetBytes() instead. You probably need to update your decrypt code to use System.Text.Encoding.UTF8.GetString() also.

rwallacej

ASKER

thanks for help,

I changed encrypt code per your comments to
DES.Key = MD5.ComputeHash(Encoding.UTF8.GetBytes(key))
DES.Mode = CipherMode.ECB
Dim DESEncrypt As ICryptoTransform = DES.CreateEncryptor()
Dim Buffer As Byte() = ASCIIEncoding.UTF32.GetBytes(stringToEncrypt)
Return Convert.ToBase64String(DESEncrypt.TransformFinalBlock(Buffer, 0, Buffer.Length))

the encrypted string is the now different.

I changed the decrypt code from what it was to
DES.Key = MD5.ComputeHash(System.Text.Encoding.UTF8.GetBytes(key))
DES.Mode = CipherMode.ECB
Dim DESDecrypt As Security.Cryptography.ICryptoTransform = DES.CreateDecryptor()
Dim Buffer As Byte() = Convert.FromBase64String(encryptedString)
Return ASCIIEncoding.ASCII.GetString(DESDecrypt.TransformFinalBlock(Buffer, 0, Buffer.Length))

but this does not decrypt string right

further help appreciated, thanks

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wdosanjos

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rwallacej

ASKER

Thanks