public void FindPrefixLength()
{
EncryptionOracleWithRandomPrefix eo = new EncryptionOracleWithRandomPrefix();
int expected = eo.RandomPrefixLength;
RandomPrefixAESCracker cracker = new RandomPrefixAESCracker(unknownString);
int actual = cracker.FindRandomPrefixLength();
Assert.AreEqual(expected, actual);
}
public int FindRandomPrefixLength()
{
int blockSize = 16;
_randomPrefixLength = 1;
EncryptionOracleWithRandomPrefix encryption = new EncryptionOracleWithRandomPrefix();
string[] firstBlock = new string[blockSize];
firstBlock[0] = encryption.EncryptConsistentKey("", base.unknownString).Substring(0, blockSize).ToString();
for (int i = 1; i < blockSize; i++)
{
firstBlock[i] = encryption.EncryptConsistentKey(new String('A', i), base.unknownString).Substring(0, blockSize).ToString();
if (firstBlock[i] == firstBlock[i - 1])
{
_randomPrefixLength = 17 - i;
break;
}
}
return(_randomPrefixLength.Value);
}
