February 26, 2002
Practical Aspects of Modern Cryptography
34
Elliptic Groups
n
(x
1
,y
1
)
´
(x
2
,y
2
) = (x
3
,y
3
)
n
n
x
3
= ((y
2
-y
1
)/(x
2
-x
1
))
2
- x
1
- x
2
n
y
3
= -y
1
+ ((y
2
-y
1
)/(x
2
-x
1
)) (x
1
- x
3
)
n
n
when x
1
¹
x
2