SHA-1 — 160-bit — an older secure hash, now effectively retired

SHA-1 is a function that produces a 160-bit (40-char) hash and was once widely used in Git, TLS, and certificates.

A real-world collision was disclosed in 2017, proving it insecure. New systems should replace it with SHA-256 or stronger, and its use should be avoided except for compatibility purposes.

Type

Cryptographic hash (legacy)

Bits

160

Output length

40 hex chars

Example · hash of "hello"

aaf4c61ddcc5e8a2dabede0f3b482cd9aea9434d

When to use it

Identifying legacy Git commits and tags
Verifying compatibility with older systems
Non-security fingerprints (not recommended for new use)

Hash with this algorithm