Main step of GOST 28147-89: Difference between revisions

{{task|Encryption}}

 

 

Implement the main step of this encryption algorithm.

 

=={{header|C}}==

Version with packed replacement table.

 

static unsigned char k65[256];

static unsigned char k43[256];

k43[x>> 8 & 255] << 8 | k21[x & 255];

return x<<11 | x>>(32-11);

 

 

{

}

 

}

 

{

UINT_64 N;

S = N1 + X % 0x4000000000000;

S = ReplaceBlock(S);

N2 = N1;

N1 = S;

return SWAP32(N2,N1);

 

Variable "BS" is the replacement table.

 

 

 

=={{header|Glagol}}==

 

=={{header|Go}}==

 

import "fmt"

type gost struct {

k87, k65, k43, k21 [256]byte

}

 

g.k21[i] = s[1][i>>4]<<4 | s[0][i&15]

}

return &g

}

// code above adapted from posted C code

 

 

var cbrf = sBox{

{4, 10, 9, 2, 13, 8, 0, 14, 6, 11, 1, 12, 7, 15, 5, 3},

}

 

key32 := u32(key)

input1 := u32(input[:4])

input2 := u32(input[4:])

 

g := newGost(&cbrf)

fmt.Printf("[%02x]", b)

}

fmt.Println()

{{out}}

<pre>

</pre>

 

 

 

 

# sboxes from http://en.wikipedia.org/wiki/GOST_(block_cipher)

[4, 10, 9, 2, 13, 8, 0, 14, 6, 11, 1, 12, 7, 15, 5, 3],

[14, 11, 4, 12, 6, 13, 15, 10, 2, 3, 8, 1, 0, 7, 5, 9],

[4, 11, 10, 0, 7, 2, 1, 13, 3, 6, 8, 5, 9, 12, 15, 14],

[13, 11, 4, 1, 3, 15, 5, 9, 0, 10, 14, 7, 6, 8, 2, 12],

);

 

 

}

 

}

 

my @input = 0x21, 0x04, 0x3B, 0x04, 0x30, 0x04, 0x32, 0x04;

my @key = 0xF9, 0x04, 0xC1, 0xE2;

 

 

 

 

{{out}}

<pre>

</pre>

 

=={{header|Tcl}}==

proc tcl::mathfunc::k {a b} {

variable ::GOST::replacementTable

return $textBlock

}

Note that only the <tt>idx</tt>'th row of the split-up <tt>textBlock</tt> (which contains the two pieces to intermingle/exchange at this step) is altered; it is the responsibility of the caller to iterate over all the steps through the entire plaintext/ciphertext.

 

* The contents of the segment registers unchanged.

 

.model flat

.code

ret

_gost32 endp