SHA-512 Generator

What is SHA-512?

SHA-512 is the largest of the standard SHA-2 hash functions. It maps input of any length to a fixed 512-bit digest, written as 128 hexadecimal characters. It is specified in the NIST Secure Hash Standard (FIPS 180-4) and in RFC 6234.

Where SHA-256 is built around 32-bit words, SHA-512 uses 64-bit words. The padded message is cut into 1024-bit blocks, each block is expanded into eighty 64-bit words, and eighty rounds of rotations, shifts, bitwise logic and modular addition update eight 64-bit state registers. Those registers, concatenated, form the digest. The constants that start the process are taken from the fractional parts of square and cube roots of small primes, a choice made so that nobody can suspect they were tuned to hide a weakness.

Reference values for testing any implementation:

How to use the SHA-512 generator

1. Type or paste the text into the String box.
2. Press Calculate. The 128-character hash appears in the results table, with a button to copy it.
3. Compare it with the checksum you expect, or store it as a fingerprint of that exact text.

What is hashed. The tool hashes the UTF-8 bytes of the text exactly as you typed it. Nothing is trimmed, normalised or added, and the digest is shown in lower-case hexadecimal. What affects the result:

• Exact characters. Capital letters, spaces and trailing blanks all matter, so Report and report give unrelated hashes.
• UTF-8 encoding. A plain ASCII character is one byte, é is two (c3 a9), 日 is three (e6 97 a5) and an emoji such as 😀 is four (f0 9f 98 80), which is what most languages and command-line tools do.
• Line breaks are kept as they arrive. A browser text box stores each line break as a single line-feed character (LF, byte 0a), and text pasted with Windows CR LF line endings normally arrives as LF too. The tool does not convert it to anything else, so the digest equals what printf piped into sha512sum gives for the same text. A final line break counts as a byte of its own.
• Nothing for empty input. An empty box produces no result, although the SHA-512 of an empty message is a defined value.

To get the digest of a file that uses Windows CR LF line endings, hash the file itself with a command-line tool. This page can only hash text the way a browser text box holds it.

The hash is calculated in your browser. A direct link to a result includes your input in its address, so do not share links for passwords or other secrets.

SHA-512 compared with SHA-256

Both are considered secure, and no practical attack on either full algorithm is known. A 128-bit collision margin is already far beyond reach, so the longer digest is not a necessity for security. The practical differences are speed and size. On a 64-bit processor without dedicated SHA-256 instructions, SHA-512 often hashes long inputs faster per byte, because it processes 128 bytes per block using native 64-bit arithmetic. On 32-bit and many embedded devices SHA-256 is faster. The result is twice as long to store or print.

Variants: SHA-384, SHA-512/256 and SHA-512/224

The same core algorithm is reused with different starting values and a shortened output:

• SHA-384 keeps the first 384 bits (96 hex characters) of a SHA-512-style computation with its own initial values.
• SHA-512/256 and SHA-512/224 truncate to 256 and 224 bits. They give SHA-256-sized output with SHA-512's speed on 64-bit machines, and because part of the internal state is never revealed, they resist length-extension attacks.

These are not simply the first characters of a normal SHA-512 hash: the different initial values change every digit. If you cut a SHA-512 hash down by hand, the result is not a standard SHA-384 or SHA-512/256 value.

Where SHA-512 is used

• Ed25519 signatures use SHA-512 internally, as part of SSH keys, signed software and many modern protocols.
• Linux password hashes that start with $6$ use the SHA-512-crypt scheme. It is a salted scheme that repeats SHA-512 thousands of times, not a single SHA-512 of the password, and newer systems often prefer yescrypt.
• Cryptocurrency wallets: BIP-32 key derivation uses HMAC-SHA-512, and BIP-39 turns a mnemonic phrase into a seed with PBKDF2 and HMAC-SHA-512.
• Integrity checks: many Linux distributions publish SHA-512 checksum files, and Subresource Integrity attributes can pin a script to a sha512- hash.
• Long-term fingerprints where a larger security margin is wanted by policy.

A single SHA-512 is not suitable for storing user passwords, salted or not. It is built to be fast, so attackers can test many billions of guesses per second. Use a deliberately slow, salted, purpose-built scheme such as Argon2, scrypt or bcrypt, or PBKDF2 with many iterations.

For a shorter modern digest see the SHA-256 generator. The SHA1 generator and MD5 generator cover older algorithms with known collision attacks, and the random password generator is the right tool when you need a secret rather than a fingerprint.