11 ms·
In this case yes as md5 has a lower bit size and both algos are broken. When done correctly, it increases the security. It's like encrypting a file with AES an
by dannyw 5y ago
In this case yes as md5 has a lower bit size and both algos are broken.
When done correctly, it increases the security. It's like encrypting a file with AES and then encrypting it with Twofish and then Serpent.
The security is actually the strongest link; not the weakest.
That's why bitcoin addresses use SHA256(RIPEMD160(X)) for output into a 160 bit hash.
- atq2119 5y agoThe "when done correctly" is a huge caveat, given that what you're replying to does it incorrectly. If X and Y collide, so that SHA-1(X) = SHA-1(Y), then f(SHA-1(X)) = f(SHA-1(Y)) no matter what f is -- so you get a collision. Concatenating the outputs of the hash functions fixes that particular issue. But concatenating makes preimage attacks easier.