Dear all,
I need some help with encrypting/decrypting a file. I've tried to use DES encryption as follows:
The problem is that I get an OutOfMemory error if the input file is too big. If I split the input file in chunks (I tried 64k chunks) it only works with AES/CFB encryption, which is not supported by many devices, while regular AES/ECB or AES/CBC fails. The tutorial http://docstore.mik.ua/orelly/java-ent/security/ch13_05.htm explains the difference, but I have not been able to find a solution splitting the file.
I've been searching in Android Developers and there is an object called "CipherInputStream" (https://developer.android.com/reference/javax/crypto/CipherInputStream.html) that could do the trick: it is supposed to be a virtual stream linked to InputStream doing the encryption so you just need to File.Copy2 it to an OutputStream, but it is not included in Agraham's Encryption Library. I'm not familiar to java. Could it be possible to build such a stream using the reflection library, or wrap the function in some way?
Thanks
I need some help with encrypting/decrypting a file. I've tried to use DES encryption as follows:
B4X:
Dim Ins As InputStream
Dim Outs, Out2 As OutputStream
Dim data() As Byte
Dim k As KeyGenerator
Dim cph as Cipher
Dim bc As ByteConverter
k.Initialize("DES")
k.KeyFromBytes(bc.HexToBytes("8512851A5CF27849"))
InitializeCipher(cph, "DES")
cph.InitialisationVector = "8512851A5CF27849"
Outs.InitializeToBytesArray(100)
File.Copy2(Ins, Outs)
data = Starter.cph.Encrypt(Outs.ToBytesArray, k.key, True)
Out2 = File.OpenOutput(cdestino, fdestino, False)
Out2.WriteBytes(data, 0, data.length)
Out2.Close
Outs.Close
Return bc.HexFromBytes(k.KeyToBytes)The problem is that I get an OutOfMemory error if the input file is too big. If I split the input file in chunks (I tried 64k chunks) it only works with AES/CFB encryption, which is not supported by many devices, while regular AES/ECB or AES/CBC fails. The tutorial http://docstore.mik.ua/orelly/java-ent/security/ch13_05.htm explains the difference, but I have not been able to find a solution splitting the file.
I've been searching in Android Developers and there is an object called "CipherInputStream" (https://developer.android.com/reference/javax/crypto/CipherInputStream.html) that could do the trick: it is supposed to be a virtual stream linked to InputStream doing the encryption so you just need to File.Copy2 it to an OutputStream, but it is not included in Agraham's Encryption Library. I'm not familiar to java. Could it be possible to build such a stream using the reflection library, or wrap the function in some way?
Thanks