Hash

Hash data quickly for identifiers, integrity checks, and tooling when building on Polkadot with Pop CLI.

When you're building on Polkadot, you'll often need hashes — to verify files, derive stable identifiers, or work with chain primitives. The pop hash command gives you a fast, convenient way to generate these hashes without juggling separate tools.

You can also run the command as pop h.

What you can use it for

• Verify the integrity of artifacts (WASM, configs, datasets) before committing or deploying.

• Turn strings or hex into deterministic IDs for testing or scripting.

• Hash raw transaction/storage bytes when inspecting or debugging.

• Produce quick, non-cryptographic checksums during development loops.

Quick examples

# Verify a string or small blob (cryptographic)
pop hash sha2 256 "hello world"

# Hash raw hex bytes (great for tx/storage inspection)
pop hash keccak 256 0x68656c6c6f776f726c64

# Check a runtime you are about to deploy
pop hash blake2 256 /path/to/your/file.wasm

# Append the original bytes to the hash (BLAKE2 or TwoX only)
pop hash blake2 256 --concat "hello world"

Supported algorithms and lengths

Subcommand	Alias	Lengths (bits)	--concat
blake2	b2	64, 128, 256, 512	Yes
keccak	kk	256, 512	No
sha2	s2	256	No
twox	xx	64, 128, 256	Yes

Input handling

The positional data argument is inspected in this order:

• If it matches an existing path, Pop reads the file contents. The file must be 3 MiB or smaller.

• If it starts with 0x, Pop parses it as hex bytes.

• Otherwise, Pop hashes the raw string bytes.

Output

Pop prints the hash as lowercase hex without a 0x prefix. If you use --concat, the output is the hash bytes followed by the original input bytes, all hex-encoded.

Errors and constraints

• Unsupported length: unsupported length: <length>

• Path exists but is not a file: specified path is not a file

• File too large: file size exceeds maximum code size

Tips

• Input can be plain text, 0x-prefixed hex, or a file path — Pop detects it for you.

• Choose the algorithm that fits the job:

  • SHA-2: dependable, broadly used.

  • BLAKE2: fast and secure (widely used in the Polkadot ecosystem).

  • Keccak: common in EVM tooling and ecosystems.

  • xxHash (TwoX): very fast, non-cryptographic for dev workflows.

• Pick an output length that matches your target (256-bit is a solid default; 512-bit for extra margin, 64/128-bit for speedier non-crypto checks).