12 digits 3des?

[moraldo]

HAPPY NEW YEAR ALL satpimps.co.uk
if any one help me !!
can make 3des mode from 12 digits
if ok any exe use to make this
thanks

[007.4]

I do not understand your question.

3DES requires the use of three 8 byte keys. However, often just two are used and the first and third have the same value.

3DES is just DES repeated three times using either

"encrypt with key1 - decrypt with key 2 - encrypt with key 3" (but as mentioned, key 3 could be key 1 again). This is known as DED.

OR

"decrypt with key1 - encrypt with key 2 - decrypt with key 3" (but as mentioned, key 3 could be key 1 again). This is known as EDE.

Each 8 byte key constsist of 64 bits but if I remember correctly only 56 bits are actually used for DES.

I cannot see how just 12 digits could be used - unless they were repeated to fill out the whole key or each key had very low entropy. (Which is known for some providers).

HTH

007.4

[moraldo]

thanks
from 64 bits ..how make 3des?? methode
ex:

FB 94 A2 0C 9D 30 A4 36 E9 69 2A 1E 7F E1 5B 35
64 E3 91 16 11 06 E0 25 D9 E7 C1 34 D9 A9 EF 8C
65 E4 5E 3E 49 AE 2F 32 54 07 09 D0 23 33 00 ED
21 72 65 FC 9D F8 A9 90 02 D7 7C AD E6 5B 13 AB
16 per 16 bits or how
please explain me just this

[007.4]

Your question makes no sense. Sorry.

What exactly are you trying to do?

[Eugenie]

Moraldo...those are 64 bytes you posted, not bits. Either way, regular DES (ECB) uses a 64 bit (8 byte) key were the eighth bit of every byte is a parity bit which is used for data transfer error detection....so only a 56 bit encryption strength remains. Like 007.4 described quite correctly, TripleDES simply runs the regular 56-bit algo 3 times using 2 or 3 56-bit keys resulting in a 168 bit encryption strength. 12 bytes for genuine TripleDES...nope, that's not the way it works. 14 bytes is the minimum if one would disregard the error detection bits.

You are posting this in the BISS section...tell us what it is you are trying to accomplish. I get the feeling you have gotten on the wrong end of things.

[007.4]

I get the feeling you have gotten on the wrong end of things.

I agree!!! :)

[moraldo]

Eugenie
Thanks !!
i have understand now
BISS E also BISS 1 :)
happy new year