Initialization Vector
Encryption work by taking a number of text blocks and then applies a key to these to produce cipher .blocks. Cipher blocks could end up being the same for the same input text. Thus an intruder could try and guess the cipher text. This is knows as electronic code book.You will find that every time you encrypt, you will find that every time you encrypt you will get the same value. Apart from using a password to generate an encryption key, which complete decimates the key space, we have the problem of the algorithm used to process the plain text. If this is ECB then we have repeating cipher blocks for the same plain text. If I take "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" and encrypt with 3-DES and a key of "beginner12345" we get: encrypted: DDE22EE186FA0425 DDE22EE186FA0425 DDE22EE186FA0425 DDE22EE186FA0425 DDE22EE186FA0425 DDE22EE186FA0425 DDE22EE186FA0425 B2460B702A2508AE Where we can see that the "a...a" values are always code...