Talk:Main step of GOST 28147-89: Difference between revisions

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task specifics

Hi,

What is goal of the task?
How does one know one has completed the task?
Do you have sample tests and sample output?

- Thanks. --Paddy3118 20:22, 31 August 2012 (UTC)

Hi!

The goal of the task is the comparison of programming languages for the implementation of some specific cryptographic algorithm, originally designed for efficient execution on 32-bit and 64-bit machines (though created in the 70's), while it operates with a 4-bit block; comparison of low-level with high-level languages in this aspect for the sake of brevity and clarity of code execution speed, consumption of computer resources and so on.
The task can be considered solved if the algorithm is implemented only true converts the input data.
Verification example can be used as follows:

the input is a text block size of 8 bytes:

[21][04][3B][04][30][04][32][04];

and item key, size 4 bytes:

[F9][04][C1][E2].

Incoming text block is divided into two parts:

[21][04][3B][04] и [30][04][32][04].

First we add modulo 2³² with the received key element, the result is

[1A][09][FC][E6].

Further, in this block is replaced with the replacement table. Are replaced by:

[A] to [1], [1] to [B], [9] to [F], [0] to [7], [C] to [0], ::[F] to [E], [6] to [5] and [E] to [8].

Finally, we obtain

[B1][7F][E0][85].

Next is the cyclic shift of reading towards senior level by 11 bits:

[2F][8C][FD][03].

This value is made up bit by bit modulo 2 with the second part on the input 8-bit block, the result is

[1F][88][CF][07].

Now is 8-byte block of data in the first part of which is located just obtained value, and the second - the first part was on the input 8-byte block. The resulting value

[1F][88][CF][07][21][04][3B][04]

and will be the result of the step.

Русский 18:54, 1 September 2012 (UTC)

@@ Line 6: / Line 6: @@
 - Thanks. --[[User:Paddy3118|Paddy3118]] 20:22, 31 August 2012 (UTC)
+: Hi!
+:* The goal of the task is the comparison of programming languages for the implementation of some specific cryptographic algorithm, originally designed for efficient execution on 32-bit and 64-bit machines (though created in the 70's), while it operates with a 4-bit block; comparison of low-level with high-level languages in this aspect for the sake of brevity and clarity of code execution speed, consumption of computer resources and so on.
+:* The task can be considered solved if the algorithm is implemented only true converts the input data.
+:* Verification example can be used as follows:
+::the input is a text block size of 8 bytes:
+:: <code>[21][04][3B][04][30][04][32][04]</code>;
+::and item key, size 4 bytes:
+:: <code>[F9][04][C1][E2]</code>.
+::Incoming text block is divided into two parts:
+:: <code>[21][04][3B][04]</code> и <code>[30][04][32][04]</code>.
+::First we add modulo 2<sup>32</sup> with the received key element, the result is
+:: <code>[1A][09][FC][E6]</code>.
+::Further, in this block is replaced with the replacement table. Are replaced by:
+:: <code>[A]</code> to <code>[1]</code>, <code>[1]</code> to <code>[B]</code>, <code>[9]</code> to <code>[F]</code>, <code>[0]</code> to <code>[7]</code>, <code>[C]</code> to <code>[0]</code>, ::<code>[F]</code> to <code>[E]</code>, <code>[6]</code> to <code>[5]</code> and <code>[E]</code> to <code>[8]</code>.
+::Finally, we obtain
+:: <code>[B1][7F][E0][85]</code>.
+::Next is the cyclic shift of reading towards senior level by 11 bits:
+:: <code>[2F][8C][FD][03]</code>.
+::This value is made up bit by bit modulo 2 with the second part on the input 8-bit block, the result is
+:: <code>[1F][88][CF][07]</code>.
+::Now is 8-byte block of data in the first part of which is located just obtained value, and the second - the first part was on the input 8-byte block. The resulting value
+:: <code>[1F][88][CF][07][21][04][3B][04]</code>
+::and will be the result of the step.
+: [[User:Русский|Русский]] 18:54, 1 September 2012 (UTC)