There is no way of finding b but what about others ??
f(s, p) is a function that encrypts s with p[password]
g(s, p) is a function that decrypts s with p[password]
f(s, p) NOT= f(p, s) and g(s, p) NOT= f(p, s)
e.g.
if X = f(s, p) then s = g(X, p)
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after encryption abcd becomes IJKL where
I = f(a, p)
J = f(I, c)
K = f(J, d)
L = f(d, p)
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Now I know only IJKL, and p
Its easy to decrypt a and d but How can I decrypt b and c ??
Is it possible ??