SHA-384 — The 96-Character Digest from the SHA-2 Family

What is SHA-384?

SHA-384 is a cryptographic hash function in the SHA-2 family, standardized by NIST in 2001. It produces a 384-bit digest displayed as 96 hexadecimal characters.

SHA-384 is essentially SHA-512 run with different initial values and the output truncated to 384 bits. This makes it faster than independently designed 384-bit hashes — it reuses the optimized SHA-512 pipeline.

SHA-384 vs the SHA-2 Family

SHA-384 sits between SHA-256 and SHA-512 in the SHA-2 family:

SHA-384 and SHA-512 share the same underlying algorithm — 80 rounds with 64-bit arithmetic and 1024-bit blocks. They differ only in their initialization constants and output length (SHA-384 truncates SHA-512’s state before output).

How SHA-384 Works

SHA-384 follows the same four-step process as SHA-512:

SHA-384 Output Format

Example outputs:

Where SHA-384 is Used

SHA-384 Performance

Since SHA-384 uses the same 64-bit arithmetic engine as SHA-512, performance characteristics are nearly identical:

• On 64-bit CPUs: slightly faster than SHA-256 per byte for large inputs (wider words, more bits per operation)
• On 32-bit CPUs: significantly slower (64-bit operations emulated)
• Hardware acceleration: Intel and ARM both provide SHA-512 instructions that also accelerate SHA-384

When to Choose SHA-384

Computing SHA-384 Hashes

echo -n "hello" | sha384sum
sha384sum filename.txt

echo -n "hello" | shasum -a 384
shasum -a 384 filename.txt

import hashlib
digest = hashlib.sha384(b"hello").hexdigest()
print(digest)

const crypto = require('crypto');
const hash = crypto.createHash('sha384').update('hello').digest('hex');
console.log(hash);

Or use the Hash Generator for instant in-browser computation across all SHA-2 variants.

Key Takeaways

• SHA-384 produces a 96-character hexadecimal digest (384 bits)
• It’s SHA-512 internally, with different init values and truncated output
• Fully secure — larger security margin than SHA-256
• Used in TLS cipher suites, P-384 signatures, and government security requirements
• On 64-bit CPUs, performance is comparable to or faster than SHA-256
• For most applications, SHA-256 is sufficient; SHA-384 when compliance demands it