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 ??