aria: comment implementation of A transform

The line-by-line comments were generated using the following Python 3 script:

 #!/usr/bin/python3

class Atom:
    def __init__(self, val):
        self.v = val

    def __str__(self):
        return self.v

    def p1(self):
        v = self.v
        return Atom(v[1] + v[0] + v[3] + v[2])

    def p2(self):
        v = self.v
        return Atom(v[2] + v[3] + v[0] + v[1])

    def __xor__(self, other):
        return Sum(self.tuple() + other.tuple())

    def tuple(self):
        return (self,)

class Sum:
    def __init__(self, terms):
        self.t = terms
        assert(type(terms) == tuple)
        for t in terms:
            assert(type(t) == Atom)

    def __str__(self):
        return '+'.join(sorted((str(t) for t in self.t),
                        key=lambda v: int(v, 16)))

    def p1(self):
        return Sum(tuple(t.p1() for t in self.t))

    def p2(self):
        return Sum(tuple(t.p2() for t in self.t))

    def tuple(self):
        return self.t

    def __xor__(self, other):
        return Sum(self.t + other.tuple())

class LoggingDict(dict):
    def __setitem__(self, key, val):
        print(key, '=', val)
        dict.__setitem__(self, key, val)

    def set(self, key, val):
        dict.__setitem__(self, key, val)

env = LoggingDict()

env.set('ra', Atom('0123'))
env.set('rb', Atom('4567'))
env.set('rc', Atom('89ab'))
env.set('rd', Atom('cdef'))
env.set('ARIA_P1', lambda x: x.p1())
env.set('ARIA_P2', lambda x: x.p2())

code = """
ta  =   rb;
rb  =   ra;
ra  =   ARIA_P2( ta );
tb  =   ARIA_P2( rd );
rd  =   ARIA_P1( rc );
rc  =   ARIA_P1( tb );
ta  ^=  rd;
tc  =   ARIA_P2( rb );
ta  =   ARIA_P1( ta ) ^ tc ^ rc;
tb  ^=  ARIA_P2( rd );
tc  ^=  ARIA_P1( ra );
rb  ^=  ta ^ tb;
tb  =   ARIA_P2( tb ) ^ ta;
ra  ^=  ARIA_P1( tb );
ta  =   ARIA_P2( ta );
rd  ^=  ARIA_P1( ta ) ^ tc;
tc  =   ARIA_P2( tc );
rc  ^=  ARIA_P1( tc ) ^ ta;
"""

exec(code, env)
This commit is contained in:
Manuel Pégourié-Gonnard 2018-02-26 14:10:23 +01:00
parent 35ad891aee
commit f205a012b8

View File

@ -78,7 +78,7 @@ static void mbedtls_zeroize( void *v, size_t n ) {
#endif
/*
* modify byte order ( A B C D ) -> ( B A D C ), i.e. swap pairs of bytes
* modify byte order: ( A B C D ) -> ( B A D C ), i.e. swap pairs of bytes
*
* This is submatrix P1 in [1] Appendix B.1
*/
@ -93,30 +93,49 @@ static void mbedtls_zeroize( void *v, size_t n ) {
/*
* ARIA Affine Transform
* (ra, rb, rc, rd) = state in/out
* (a, b, c, d) = state in/out
*
* If we denote the first by of input by 0, ..., the last byte by f,
* then inputs are: a = 0123, b = 4567, c = 89ab, d = cdef.
*
* Reading [1] 2.4 or [2] 2.4.3 in colums and performing simple
* rearrangements on adjacent pairs, output is:
*
* a = 3210 + 4545 + 6767 + 88aa + 99bb + dccd + effe
* = 3210 + 4567 + 6745 + 89ab + 98ba + dcfe + efcd
* b = 0101 + 2323 + 5476 + 8998 + baab + ecec + ffdd
* = 0123 + 2301 + 5476 + 89ab + ba98 + efcd + fedc
* c = 0022 + 1133 + 4545 + 7667 + ab89 + dcdc + fefe
* = 0123 + 1032 + 4567 + 7654 + ab89 + dcfe + fedc
* d = 1001 + 2332 + 6644 + 7755 + 9898 + baba + cedf
* = 1032 + 2301 + 6745 + 7654 + 98ba + ba98 + cdef
*
* Note: another presentation of the A transform can be found as the first
* half of App. B.1 in [1] in terms of 4-byte operators P1, P2, P3 and P4.
* The implementation below uses only P1 and P2 as they are sufficient.
*/
static inline void aria_a( uint32_t *a, uint32_t *b,
uint32_t *c, uint32_t *d )
{
uint32_t ta, tb, tc;
ta = *b;
*b = *a;
*a = ARIA_P2( ta );
tb = ARIA_P2( *d );
*d = ARIA_P1( *c );
*c = ARIA_P1( tb );
ta ^= *d;
tc = ARIA_P2( *b );
ta = ARIA_P1( ta ) ^ tc ^ *c;
tb ^= ARIA_P2( *d );
tc ^= ARIA_P1( *a );
*b ^= ta ^ tb;
tb = ARIA_P2( tb ) ^ ta;
*a ^= ARIA_P1( tb );
ta = ARIA_P2( ta );
*d ^= ARIA_P1( ta ) ^ tc;
tc = ARIA_P2( tc );
*c ^= ARIA_P1( tc ) ^ ta;
ta = *b; // 4567
*b = *a; // 0123
*a = ARIA_P2( ta ); // 6745
tb = ARIA_P2( *d ); // efcd
*d = ARIA_P1( *c ); // 98ba
*c = ARIA_P1( tb ); // fedc
ta ^= *d; // 4567+98ba
tc = ARIA_P2( *b ); // 2301
ta = ARIA_P1( ta ) ^ tc ^ *c; // 2301+5476+89ab+fedc
tb ^= ARIA_P2( *d ); // ba98+efcd
tc ^= ARIA_P1( *a ); // 2301+7654
*b ^= ta ^ tb; // 0123+2301+5476+89ab+ba98+efcd+fedc OUT
tb = ARIA_P2( tb ) ^ ta; // 2301+5476+89ab+98ba+cdef+fedc
*a ^= ARIA_P1( tb ); // 3210+4567+6745+89ab+98ba+dcfe+efcd OUT
ta = ARIA_P2( ta ); // 0123+7654+ab89+dcfe
*d ^= ARIA_P1( ta ) ^ tc; // 1032+2301+6745+7654+98ba+ba98+cdef OUT
tc = ARIA_P2( tc ); // 0123+5476
*c ^= ARIA_P1( tc ) ^ ta; // 0123+1032+4567+7654+ab89+dcfe+fedc OUT
}
/*