SHA-512 is the long member of the SHA-2 family: a 512-bit hash written as 128 hex characters. On 64-bit computers it is often faster than SHA-256, and it is used for npm package integrity, Linux password files, and long-term signatures.
SHA-512 or SHA-256?
Both are secure. SHA-512 gives a longer hash and often runs faster on 64-bit CPUs, while SHA-256 is shorter and more widely expected. SHA-384 is SHA-512 with a different starting point, cut to 384 bits.
Where SHA-512 is used
npm lockfiles, whose integrity fields start with sha512-.
Linux password hashes that begin with $6$, which run SHA-512 many thousands of times.
File checksums for large downloads.
Checking a download
Click Hash a file and choose the file, then paste the checksum published by the site you downloaded it from into Check against a hash. A match means your copy is identical to the original, byte for byte.
From the command line
# macOS
shasum -a 512 file.zip
# Linux
sha512sum file.zip
# Windows (PowerShell)
Get-FileHash file.zip -Algorithm SHA512
Frequently asked questions
How long is a SHA-512 hash?
512 bits, written as 128 hexadecimal characters.
Is SHA-512 more secure than SHA-256?
Both have no known practical attacks. SHA-512's longer output gives a larger safety margin, but SHA-256 is strong enough for nearly every use.
Why is the npm integrity value different from this hash?
npm writes the SHA-512 hash in Base64, after sha512-. This tool shows it in hex; the bytes are the same.