Is a Double SHA-256 hash reversible?

No. Double SHA-256 is a one-way hash; you cannot reverse it. You can only guess inputs and compare, which is what hashcat and John do.

What is the hashcat mode for Double SHA-256?

Use `-m 1420` to tell hashcat to treat the input as Double SHA-256.

How long does it take to crack Double SHA-256?

Double SHA-256 is fast to compute, so weak passwords often fall in seconds to minutes on a GPU; strong, long passwords remain infeasible.

Is a Double SHA-256 hash reversible?

No. Double SHA-256 is a one-way hash; you cannot reverse it. You can only guess inputs and compare, which is what hashcat and John do.

What is the hashcat mode for Double SHA-256?

Use `-m 1420` to tell hashcat to treat the input as Double SHA-256.

How long does it take to crack Double SHA-256?

Double SHA-256 is fast to compute, so weak passwords often fall in seconds to minutes on a GPU; strong, long passwords remain infeasible.

How to identify and crack a Double SHA-256 hash

Double SHA-256 is a raw / unsalted hash type. It is fast and typically unsalted, which makes weak passwords recoverable quickly on consumer GPU hardware. This page shows how to recognise it and the exact commands to attack it.

All identification runs locally in WebAssembly. The commands below write the hash to a local file on your machine — nothing is sent to this site.

Identifying the hash

The hash identifier on the home page detects Double SHA-256 entirely in your browser — your hash is never uploaded. A typical example looks like this:

7df1e1c5fe97f1cffbd61492054351c5d6371a4c6614f0a98f752b4a4f6e87e4

Cracking Double SHA-256 with hashcat

Save the hash to a file and run hashcat in mode -m 1420. Start with a wordlist such as rockyou.txt:

echo '7df1e1c5fe97f1cffbd61492054351c5d6371a4c6614f0a98f752b4a4f6e87e4' > hash.txt && hashcat -m 1420 hash.txt /usr/share/wordlists/rockyou.txt

Add a rule set to mutate dictionary words (capitalisation, leetspeak, appended digits) and dramatically widen coverage:

echo '7df1e1c5fe97f1cffbd61492054351c5d6371a4c6614f0a98f752b4a4f6e87e4' > hash.txt && hashcat -m 1420 hash.txt /usr/share/wordlists/rockyou.txt -r /usr/share/hashcat/rules/best64.rule