Question How reliable is SHA-256

[ditrate]

I never used hash checking, but now I started to use SHA-256 for my files, should I change it for a different hashing type (MD5 or SHA-1)?

 

[rgd1101]

what do you mean how reliable?

 

[USAFRet]

I never used hash checking, but now I started to use SHA-256 for my files, should I change it for a different hashing type (MD5 or SHA-1)?

What have you read to indicate is is not a good method or algorithm?

 

[ex_bubblehead]

I never used hash checking, but now I started to use SHA-256 for my files, should I change it for a different hashing type (MD5 or SHA-1)?

If your truly that paranoid about files being altered then you take multiple chksums, generated by different algorithms, for every file. The 3 you've listed are excellent choices. It's virtually impossible to change a file in a manner that all three chksums would remain unchanged.

 

[hotaru.hino]

The only thing that makes a hashing function "useful" is how low the chances two different inputs will produce the same result. For MD5, it's 1 in 340282366920938463463374607431768211456. For SHA1 it's 1 in 1461501637330902918203684832716283019655932542976. For SHA 256 it's 1 in 115792089237316195423570985008687907853269984665640564039457584007913129639936

If you're using a hash function to verify the integrity of a file, then hashing is 100% reliable. Whether or not you'll find a problem depends on your record keeping.