Warren and Brandice were classic liberal jurists. In the context of cryptography, liberalism lies on three central supports: personal liberty, social liberty, and international liberty. These liberties construct a framework for how people can expect to be treated by their government and peers. However, this framework is not unambiguous.
The first right, that of personal liberty, is a right to be ``dealt with in accordance with the law.'' To a liberal, the law is your protection against tyranny as well as anarchy. It is a solid grounding to stand on that can be reasonably expected not to move under one's feet. It is necessary to have a rule of law that applies equally to everyone, because otherwise people will not be ruled by law but by other people, and that is defined to be the opposite of liberty.
As Warren and Brandice stated in The Right to Privacy, this applies directly to the notion of privacy. Without privacy, people have no ``freedom from inquisition into opinions that a man forms in his own mind - the inner citadel where, if anywhere, the individual must rule.''  Cryptography gives people a form of protection for their opinions; however to what extent liberalism protects these opinions outside of the realm of thoughts is debatable. To what extent this right even exist is also debatable given the use of lie detector tests, which are compulsory for some criminals and required for some jobs. Perhaps the right to sovereignty of your own thoughts, free from the ``inquisition'' of other men, does not exists. Perhaps it should.
Social liberty is the second important liberal right. It includes freedom to pursue an occupation and freedom of association. Cryptography, particularly in encrypting voice transmission and mail, helps facilitate the freedom of association, however the freedom of association in liberal parlance only extends so far as the associations themselves are liberal. This means if associations further an agenda that hurts the liberty of others, then the associations themselves are not liberal and therefore the freedom does not exist. It is difficult to distinguish between a liberal and non-liberal association protected through cryptographic means, and so whether the government has the right to control cryptography used for association despite the unknown nature of the association is debatable.
The third important liberty is international liberty. And this is where liberalism appears to require some control of cryptography. A liberal government needs to protect its citizens from encroachment by non-liberal states or groups. For instance, when Adolf Hitler threatened the liberty of Europe and Russia, the potential existed for this threat to extend to the US. To preserve the liberty of Americans, the US not only helped defeat Hitler but also seeded Europe with democratic governments.
Leonard Trelawney argues that ``There is a point at which speech becomes indistinguishable from action, and free speech may mean the right to create disorder... No modern state would tolerate a form of religious worship which should include cannibalism, human sacrifice, or the burning of witches.''  This would appear to directly address the issue of cryptographic computer code not being protected by free speech because computer code fits the description of speech that is almost indistinguishable from action. In the RIAA vs 2600 appeals case, the judges treated the decss code as both a work of protected speech and something indistinguishable from action... a device for which the creator has a responsibility for. It is analogous to a Rube Goldberg machine that performs lethal injections: while it may be a work of art, it may also be an illegal device. Thus, protection on free speech does not protect program code that acts as an illegal device. This ruling is very much in accordance with liberal philosophy, however ignoring liberal rights in the process of preventing potentially non-liberal infringements on those rights seems, I would argue, to be sacrificing the liberal principles to save them.