SHA-512 and SHA-384
SHA-512 is the largest member of the SHA-2 family standardised by NIST in FIPS 180-4. It produces a 512-bit digest, written as 128 hexadecimal characters, and has no known practical weaknesses. It appears in file checksums for Linux distributions and package managers, in HMAC-SHA512 signatures for APIs and exchanges, and inside password hashing schemes such as sha512crypt.
SHA-384 is SHA-512 with different starting values, cut to 384 bits. It is used in TLS cipher suites and wherever a shorter digest that resists length-extension attacks is preferred.
Worked example
The SHA-512 of abc begins ddaf35a193617aba and ends a54ca49f; the full value is the official FIPS 180-4 test vector, which this page reproduces exactly. Adding a single space changes every one of the 128 characters.
Hashes are not passwords
A plain SHA-512 of a password can be attacked by trying billions of guesses per second on a GPU. Password storage needs a deliberately slow, salted function such as Argon2 or bcrypt.
How this works
The page encodes your text as UTF-8 and asks the browser's Web Crypto API for the digest. SHA-512 pads the message to a multiple of 1,024 bits and runs 80 rounds per block over eight 64-bit state words, as defined in FIPS 180-4. SHA-384 uses the same steps with different initial values and keeps the first 384 bits. The result is shown in lowercase hexadecimal. Test vectors from the standard are checked on every build. Nothing leaves your browser.
Frequently asked
Is SHA-512 more secure than SHA-256?
Both have no known practical attacks. SHA-512 has a larger margin and is often faster on 64-bit machines; SHA-256 is more widely supported.
How long is a SHA-512 hash?
512 bits: 128 hexadecimal characters or 64 bytes. SHA-384 is 96 hex characters.
Can I use SHA-512 to store passwords?
Not on its own. Use a slow, salted password hash such as Argon2, scrypt or bcrypt.
Is my text uploaded?
No. The browser computes the hash locally.
Sources
Reviewed Oct 17, 2026 · test vectors fixtures/dev/sha512-hash/