That was exactly what Labour expected when they introduced RIPA. "Oh, as a child-molesting, money laundering terrorists I could go to prison for two years if I don't reveal my key and my evil plans...or reveal the key and go down for life. Fair cop, there you go, guvnor, here's me keys".
Which is why they changed it. It now reads:
(5)A person guilty of an offence under this section shall be liable—
(a)on conviction on indictment, to imprisonment for a term not exceeding [the appropriate maximum term] or to a fine, or to both;
(b)on summary conviction, to imprisonment for a term not exceeding six months or to a fine not exceeding the statutory maximum, or to both.
(5A)In subsection (5) ‘the appropriate maximum term’ means—
(a)in a national security case [or a child indecency case], five years; and
(b)in any other case, two years.
I seem to recall some judge thinking it should be increased to the same term as the potential offense it could be hiding, so 10+ years for failing to decrypt a file that might contain child porn (but cannot be proven to contain anything). May as well go hog wild and make it a life sentence to fail to provide a password, because you can tell they just want the good old days of "guilty until proven innocent" back.