SHA-256
The hash that secures bitcoin, certificates, and half the internet.
NIST published SHA-256 as FIPS 180. It is the hash inside Bitcoin and certificates.
NIST FIPS 180
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The bars are an original sketch of the compression step in NIST FIPS 180, not an OpenSSL file. A lawyer cleared this listing.
NIST published SHA-256 in FIPS 180. A hash turns any message into a fixed 256-bit digest: the same input always gives the same output, and you cannot run it backward. It is the hash inside bitcoin and behind the padlock in your browser.
The bars are an original sketch of the compression step, not a file from OpenSSL. The message is padded and walked in 512-bit blocks. Each block expands to sixty-four words and runs sixty-four rounds that mix eight state words. The bars are that whirl.