Editing Block cipher (section)

==Relation to other cryptographic primitives==
Block ciphers can be used to build other cryptographic primitives, such as those below. For these other primitives to be cryptographically secure, care has to be taken to build them the right way.

* [[Stream cipher]]s can be built using block ciphers. OFB mode and CTR mode are block modes that turn a block cipher into a stream cipher.
* [[Cryptographic hash function]]s can be built using block ciphers.<ref>{{cite web| url = http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=44737| title = ISO/IEC 10118-2:2010 ''Information technology — Security techniques — Hash-functions — Part 2: Hash-functions using an n-bit block cipher''}}</ref>{{sfn|Menezes|van Oorschot|Vanstone|1996|loc=Chapter 9: Hash Functions and Data Integrity}} See the [[one-way compression function]] for descriptions of several such methods. The methods resemble the block cipher modes of operation usually used for encryption.
* [[Cryptographically secure pseudorandom number generator]]s (CSPRNGs) can be built using block ciphers.<ref>{{cite journal| url = http://csrc.nist.gov/publications/nistpubs/800-90A/SP800-90A.pdf | title = NIST Special Publication 800-90A ''Recommendation for Random Number Generation Using Deterministic Random Bit Generators''| year = 2012| doi = 10.6028/NIST.SP.800-90A| last1 = Barker| first1 = E. B.| last2 = Kelsey| first2 = J. M.}}</ref>{{sfn|Menezes|van Oorschot|Vanstone|1996|loc=Chapter 5: Pseudorandom Bits and Sequences}}
* Secure [[pseudorandom permutation]]s of arbitrarily sized finite sets can be constructed with block ciphers; see [[Format-Preserving Encryption]].
* A publicly known [[unpredictable permutation]] combined with key whitening is enough to construct a block cipher -- such as the single-key [[Even–Mansour cipher]], perhaps the simplest possible provably secure block cipher.<ref name="DKS">
[[Orr Dunkelman]], [[Nathan Keller]], and [[Adi Shamir]].
[http://eprint.iacr.org/2011/541.pdf "Minimalism in Cryptography: The Even–Mansour Scheme Revisited"].
</ref>
* [[Message authentication code]]s (MACs) are often built from block ciphers. [[CBC-MAC]], [[One-key MAC|OMAC]], and [[PMAC (cryptography)|PMAC]] are such MACs.
* [[Authenticated encryption]] is also built from block ciphers. It means to both encrypt and MAC at the same time. That is to both provide [[confidentiality]] and [[authentication]]. [[CCM mode|CCM]], [[EAX mode|EAX]], [[Galois/Counter Mode|GCM]], and [[OCB mode|OCB]] are such authenticated encryption modes.

Just as block ciphers can be used to build hash functions, like SHA-1 and SHA-2 are based on block ciphers which are also used independently as [[SHACAL]], hash functions can be used to build block ciphers. Examples of such block ciphers are [[BEAR and LION ciphers|BEAR and LION]].