Abbreviations;
- PseudoRandom Permutations : PRP
- PseudoRandom Functions : PRF
- PseudoRandom Generators :PRG
- One-Way Functions: OWF
Does "pseudorandom permutations (aka block ciphers)" mean that pseudorandom generators and block ciphers are the same concepts? Isn't it that a block cipher is a mapping: {key}x{plaintext}->{ciphertext}? Isn't it that a pseudorandom permutation is a random function: {plaintext}->{ciphertext}?
PRPs and block ciphers are synonymous. Both are defined as the keyed family of permutations ( where each permutation is selected with a key or more than one key). They are designed to have a small PRP advantage to the attacker with the same syntax security target.
Determining the exact advantage is hard like nobody showed that AES is a PRP or not in more than 20 years.
There is also ideal-block cipher ( like the random oracle) that is a model for the adversaries.
?Does "pseudorandom generators (aka stream ciphers)" mean that pseudorandom generators and stream ciphers are the same concepts? Why?
Stream ciphers (for a single fixed message number) and PRGs are more or less synonymous
PRG's
- have fixed-length output
- produce output in “one shot”
If we fix the output length of stream-cipher they are more or less the same thing. In general, stream ciphers
- can be viewed as producing an “infinite” stream of
pseudorandom bits, on-demand
- more flexible, more efficient
Are pseudorandom generators, pseudorandom permutations, and hash functions all keyless?
PRG and PRP are keyed. The hash function is rather a wide subject. Hash functions constructed for collision resistance like SHA-2 are keyless. HMAC, as a method of construction PRFs ( also as a MAC from hash functions like HMAC-SHA-2), is sometimes called keyed hash function.
Are one-way functions also keyless?
OWFs are not keyed.
Are one-way functions and hash functions the same concept, or very closely related concepts?
Being OWF is required of collision resistance hash functions and OWF is not synonymous with hash functions.