![]() ![]() This is probably true for all encryption algorithms derived from SymmetricAlgorithm (Aes, DES, RC2, Rijndael, TripleDES), although I just verified that for AesManaged and a MemoryStream as output Stream. If you do not call FlushFinalBlock before Close after you wrote data to be encrypted, when decrypting data, a call to Read or CopyTo method on your CryptoStream object will raise a CryptographicException exception (message: "Padding is invalid and cannot be removed"). Calling Close method just closes the CryptoStream and the output Stream. " Calling the Close method will call FlushFinalBlock. MSDN documentation on CryptoStream.FlushFinalBlock method says: If the same key and initialization vector are used for encoding and decoding, this issue does not come from data decoding but from data encoding.Īfter you called Write method on a CryptoStream object, you must ALWAYS call FlushFinalBlock method before Close method. Replace the encryptedData element with the plaintext XML element.Įxml.ReplaceData(encryptedElement, rgbOutput) Decrypt the element using the symmetric key.īyte rgbOutput = exml.DecryptData(edElement, alg) <- I GET THE EXCEPTION HERE ![]() Create an EncryptedData object and populate it.ĮncryptedData edElement = new EncryptedData() Throw new XmlException("The EncryptedData element was not found.") If the EncryptedData element was not found, throw an exception. XmlElement encryptedElement = doc.GetElementsByTagName("EncryptedData") as XmlElement Find the EncryptedData element in the XmlDocument. Private void Decrypt(XmlDocument doc, SymmetricAlgorithm alg) Rfc2898DeriveBytes p = new Rfc2898DeriveBytes(passwordBytes, saltBytes) If the cryptoMode is false, it will call the decrypt method, which is where the exception occurs: public void Cryptography(XmlDocument doc, bool cryptographyMode)Ĭonst string passwordBytes = "Password1234" //password hereīyte saltBytes = ("SaltBytes") #Dnn password decrypt software code#The encryption works fine but when I try to decrypt, I get the following exception:Ĭan anyone tell me what I can do to solve this issue? My code below is where I get the key and other data. I have been using the example provided my msdn for encrypting and decrypting an XmlDocument using the Rijndael algorithm. The benefit of hashing is that the application never needs to store the clear text password.I have looked online for what this exception means in relation to my program but can't seem to find a solution or the reason why it's happening to my specific program. If the two hashes are an exact match, the user provided a valid username and password. Other considerations Hashing algorithm selection Encryption algorithm selection Per User Salt Protection of key Computational difficulty How does the application authenticate a user with a password hash? When the application receives a username and password from a user, it performs the hashing operation on the password and compares the resulting hashed value with the password hash stored in the database for the particular user. ![]() Table 1: Differences Between Hashing and Symmetric Encryption Hashing Symmetric Encryption One-way function Reversible Operation Invertible Operation? No, Yes, For modern hashing algorithms it is not easy to reverse the hash value to obtain the original input value Symmetric encryption is designed to allow anyone with access to the encryption key to decrypt and obtain the original input value.See note below on rainbow tables, salts, etc. Anyone possessing the key can decrypt an encrypted value to obtain the original value. ![]()
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