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m ≥ a b
m m | (a − b )
a
b
m
a ≡ b (mod m)
m (a − b )
a ≡ b (mod m)
≡
(mod
)
≡ (mod )
(
|(
−
) =
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m ∈ Z m
a
a ≡ a(mod m)
a
b
a ≡ b (mod m)
b ≡ a(mod m)
a
b
c
a ≡ b (mod m)
b ≡ c (mod m)
a ≡ c (mod m)
m
Z
m
Zm
· · · ≡ −
≡ −
≡
≡
≡
. . . (mod
)· · · ≡ −
≡ −
≡
≡
≡
. . . (mod )
· · · ≡ − ≡ −
≡
≡
≡
. . . (mod
)
· · · ≡ − ≡ −
≡
≡
≡
. . . (mod
)
· · · ≡ − ≡ − ≡ ≡ ≡ . . . (mod )
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a b c m m > a ≡ b (mod m)
a + c ≡ b + c (mod m)
a − c ≡ b − c (mod m)
ac ≡ bc (mod m)
≡ (mod )
=
+
≡
+
=
(mod
)
= − ≡ − = (mod )
=
× ≡ × = (mod )
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a, b , c , m ∈ Z c = m > mdc (c , m) = d
ac ≡ bc (mod m)
a ≡ b (mod m
d )
= × ≡ = × (mod ) mdc ( , ) =
×
≡ ×
(mod
), ≡ (mod ).
a, b , c , m ∈ Z c = m > mdc (c , m) =
ac ≡ bc (mod m)
a ≡ b (mod m)
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ax ≡ b (mod m),
x ∈ Z
x ≡
(mod
)
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a, b , m ∈ Z
m >
mdc (a, m) = d
d b
ax ≡ b (mod m) d |b ax ≡ b (mod m) d
m
x i = x
+ m
d ×,
x
x ≡
(mod
)
mdc (
,
) =
|
x
=
x
= +
× = ,
x
= +
×
=
,
x
= +
×
=
,
x =
+
×
= .
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a mdc (a, m) = ax ≡ (mod m)
a
m
x ≡ (mod )
x ≡ (mod
),
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×
a, b , c , d , e , f , m ∈ Z m > mdc (∆, m) = ∆ = ad − bc =
ax + by ≡ e (mod m)
cx + dy ≡ f (mod m)
m
x ≡ ∆̄(de − bf )(mod m)
y ≡ ∆̄(af − ce )(mod m),
∆̄
∆
m
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×
x +
y ≡
(mod
)
x +
y ≡
(mod
)
.
∆ = ad − bc =
×
−
×
=
mdc (∆, m) = mdc ( , ) =
x ≡ × (de − bf ) =
× (
.
−
.
) = −
≡
(mod
)
y ≡ × (af − ce ) = × ( . − . ) = ≡ (mod ).
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f P
C
f
f −
f
P f −→ C
f −
−−→ P
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A, B , . . . Z , , . . .
P ∈ { ,
,
, . . .
}
f
{ , , , . . . }
f (P ) = P +
, x < ,
P − , x ≥
,
,
.
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f − (P ) =
P − , x < ,P +
,
x ≥
.
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f
C = f (P ) ≡ P + b (mod m).
C ∈ {
,
, . . . , m −
}
P = f − (C ) ≡ C − b (mod m).
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C = f (P ) ≡ P + b (mod m) P = f − (C ) ≡ C − b (mod m).
.
b
≡
+ b (mod
),
b =
QHGKYCUTUI =
→ = ARQUIMEDES
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f
C ≡ aP + b (mod m),
a
b
a =
b =
C ≡
P +
(mod
),
ARQUIMEDES =
→
= MBUWQSOHOI
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n
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A
B
n × k
Z
A
B
m aij ≡ b ij (mod m) ≤ i ≤ n ≤ j ≤ k A
B
m
A ≡ B (mod m),
A ≡ B (mod m).
≡ −
(mod ).
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a
x
+ a
x
+ . . . a
nx n ≡ b
(mod m)
a
x
+ a
x
+ . . . a nx n ≡ b (mod m)
. . . . . . . . . . . .
. . . . . . . . . . . .
an x + an x + . . . annx n ≡ b n(mod m)
n
AX ≡ B (mod m),
A =
a
a
. . . a
n
a
a
. . . a n
: : : :
an
an
. . . ann
, X =
x
x
:
x n
B =
b
b
:
b n
.
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A Ā n × n
AĀ ≡ ĀA ≡ I (mod m),
I
n
Ā
A
=
≡
(mod
)
=
≡
(mod
)
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A
n × n
Z
m ∈ Z
mdc (∆, m) = ∆
Ā = ∆̄Adj (A)
A
m
∆̄
∆
m
A =
a b
c d ∆ = detA = ad − bc
m
Ā = ∆̄
d −b −c a
∆̄
∆
m
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A =
.
∆ = −
mdc (∆, ) =
∆̄ =
Ā = (adj (A)) =
− − −
−
≡
(mod ).
A
m
AX ≡ B (mod m),
X = ĀB (mod m)
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n
n
E n×n
, , , . . . m − m
n
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E n×n
m
m −
t
n
p i n ×
E
p
, p
, . . . , p t
c
= Ep
, c
= Ep
, c
= Ep
, . . . , c t = Ep t
c
, c
, . . . , c t
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E =
.
detA = − ≡ (mod )
PASCAL.
.
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.
P
×
P =
.
E
P
C = EP =
.
≡
(mod
).
−→ EBQMHK .
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D = Ē (mod m)
C
P = DC
P
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(mod ) =
C
AJXGTRJXDGKKIXL
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C =
P = DC =
P
→
TEORIADOSNUMEROS →
.
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C = EP
C
P
P
C = EP E = C P
E
D
n
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CRIPTOGRAFIAELEGAL.
n =
n =
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n =
n =
→
.
→
→
,
→
,
−→
, . . .
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n =
×
P =
det (P ) = −
P
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P
P =
det (P ) = −
≡
(mod
)
= E
E =
(mod
) =
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CRIPTOGRAFIAELEGAL.
P =
,
C = EP =
.
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n =
E
×
C = EP
= E
.
×
P =
,
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P =
.
det (P )(mod
) =
= E
.
E =
−
(mod ) =
.
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=
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mdc (∆, m)
¯∆
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E
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E
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E
−→
−→
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E
P
C
−→
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