sha256-update

Arguments: context data &key start end external-format

Add data to the running SHA256 computation in context (sha256-init returns a context). data may be a string or an (unsigned-byte 8) vector.

If data is a string, the start and end keyword arguments specify character positions in the string. start defaults to 0 and end defaults to nil, equivalent to the length of the string. external-format specifies the external hashing of the string that will be used to update the context. If not specified, the default external format will be used.

If data is an (unsigned-byte 8) vector, start and end refer to locations in the vector (again defaulting to 0 and nil, meaning the length of the vector). external-format is ignored.

This function returns no values, but side-effects context.

See MD*, SHA*, HMAC, and other message digest support in miscellaneous.htm. See also digest-update.

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This page has had moderate revisions compared to the 8.2 page.
Created 2019.8.20.