# Io Reference

Digests / SHA1 / SHA1

An object for calculating SHA1 hashes. Each hash calculation should instantiate its own SHA1 instance.

Example:

    digest := SHA1 clone
    digest appendSeq("this is a message")
    out := digest md5String

appendSeq(aSequence)

Appends aSequence to the hash calculation. Returns self.
hmac(key, data)

Returns a hmac signature sequence or nil on error.
sha1

Completes the SHA1 calculation and returns the hash as a Buffer. Once this method is called, append() should not be called again on the receiver or it will raise an exception.
sha1String

Returns a string containing a hexadecimal representation of the sha1 hash.