This message digest is usually then rendered as a hexadecimal number which is 40 digits long. Hash Ladders for Shorter Lamport Signatures.md · GitHub The probability of finding any collisions is still less than 10^-9 after 500 trillion (5*10^14) years. Unlike things like sha256 or sha512 the MD5 one is a lot more predictable. What are the disadvantages of using SHA-1 for hashing passwords? Pro Git Quotes by Scott Chacon - goodreads.com > >> It's just really mixed up. $\begingroup$ What MD5 (or, ideally, a better hash function like SHA-2 or BLAKE2b) gets you is a short token that you can compare to later.Doing a byte-by-byte comparison involves reading both files entire contents from disk in order to compare them. . leaving you with about a 1- The practical full collision linked above shows why you should not be using SHA-1 anymore. (given sufficiently long input to the hash) will with overwhelming probability produce hash input that is different from the original. The git hash is made up of the following: The commit message. On a basic level, the collision-finding technique involves breaking the data down into small chunks so that changes, or disturbances, in one set of chunks is countered by twiddling bits in other chunks. In the Pro-Git Book, Scott Chacon notes that to have a probability of a SHA1-hash collision rise to 1/2, you need about 10^24 objects . An attacker would need to . The problem with SHA-1 is the collision attack that way before the actual attack shattered.io NIST dropped it in 2011 from digital signatures since finding collision has catastrophic result in Digital Signatures. With the magic constants, we expect less than 7/10 of the bits being on (we expect some collisions when adding the elements). Git can only store one half of the colliding pair, and when following a link from one object to the colliding hash name, it can't know which object the name was meant to point to. The SHA-1 digest is 20 bytes or 160 bits. Chance of short SHA1 hash collision at 7 character hash string #2 - GitHub