science vs cryptography

science and cryptography both are nouns.

Word	Noun	Adjective	Verb	Adverb
science	Yes	No	No	No
cryptography	Yes	No	No	No

As nouns, cryptography is a hyponym of science; that is, cryptography is a word with a more specific, narrower meaning than science:

science: a particular branch of scientific knowledge
cryptography: the science of analyzing and deciphering codes and ciphers and cryptograms

science (noun)	cryptography (noun)
a particular branch of scientific knowledge	act of writing in code or cipher
ability to produce solutions in some problem domain	the science of analyzing and deciphering codes and ciphers and cryptograms