4 ms·

What is the benefit of bcrypt over several million rounds of SHA-512? It seems to me that repeating the hash function is the adjustable work factor that bcrypt

What is the benefit of bcrypt over several million rounds of SHA-512? It seems to me that repeating the hash function is the adjustable work factor that bcrypt seeks to allow and SHA-2 is already in most languages without an additional library.

tedunangst 15y ago
Not much. You are perhaps a little more likely to find super-tuned GPU/FPGA implementations of SHA2 than pessimized blowfish, but it's not inconceivable for someone to write the latter. bcrypt is easier to pronounce than PBKFD2.
idlewords 15y ago
When talking about DIY crypto, the question should be turned around - what's the benefit of this over just using bcrypt?
- pnathan 15y ago
  Well, one example might be if you were implementing your crypto in a language that doesn't have bcrypt bindings. So you would either have to port bcrypt or use existing crypto code to approximate bcrypt-level security.
  - maaku 15y ago
    False choice. Why roll your own when either porting bindings to bcrypt or porting the bcrypt implementation to your language is easier and safer?
Locke1689 15y ago
No. Making Blowfish faster is equivalent to solving a hard cryptographic problem. We have a much weaker guarantee about SHA-512. While SHA is probably good enough, bcrypt is definitely better.
rmc 15y ago
What is the benefit of bcrypt over several million rounds of SHA-512? Most advances in cracking cryptographic hashes is not from Moores law, but some insight or breakthrough in the underlying algorithm. i.e. someone figures out a way to make MD5 brute forcing 2^(lots) faster. Usually these are not done overnight, but are chipped away bit by bit. We are getting there with SHA512. The edges are starting to give. Warning signs are apparent. Eventually someone will reduce it to nothingness. 1000 iterations of nothingness is nothing ness. SHA-2 is already in most languages without an additional library. Oh dear god this is a terrible way to make a security decision. You have to install software no matter what you do. Unless you're writing software with a magnet in raw machine code, you will have to install additional software. Take the few minutes to install the bcrypt library.

tedunangst 15y ago

Not much. You are perhaps a little more likely to find super-tuned GPU/FPGA implementations of SHA2 than pessimized blowfish, but it's not inconceivable for someone to write the latter. bcrypt is easier to pronounce than PBKFD2.

idlewords 15y ago

When talking about DIY crypto, the question should be turned around - what's the benefit of this over just using bcrypt?

pnathan 15y ago
Well, one example might be if you were implementing your crypto in a language that doesn't have bcrypt bindings. So you would either have to port bcrypt or use existing crypto code to approximate bcrypt-level security.
- maaku 15y ago
  False choice. Why roll your own when either porting bindings to bcrypt or porting the bcrypt implementation to your language is easier and safer?

Locke1689 15y ago

No. Making Blowfish faster is equivalent to solving a hard cryptographic problem. We have a much weaker guarantee about SHA-512. While SHA is probably good enough, bcrypt is definitely better.

rmc 15y ago

What is the benefit of bcrypt over several million rounds of SHA-512? Most advances in cracking cryptographic hashes is not from Moores law, but some insight or breakthrough in the underlying algorithm. i.e. someone figures out a way to make MD5 brute forcing 2^(lots) faster. Usually these are not done overnight, but are chipped away bit by bit. We are getting there with SHA512. The edges are starting to give. Warning signs are apparent. Eventually someone will reduce it to nothingness. 1000 iterations of nothingness is nothing ness. SHA-2 is already in most languages without an additional library. Oh dear god this is a terrible way to make a security decision. You have to install software no matter what you do. Unless you're writing software with a magnet in raw machine code, you will have to install additional software. Take the few minutes to install the bcrypt library.