Monday, November 08, 2010 at 12:01 AM.

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system.verbs.apps.OAuth.getHmac

on getHmac (data, key) {
	<<Changes
		<<3/27/06; 5:57:47 PM by LMO
			<<Initial implementation, stolen from Digest::HMAC in Perl
	local (BLOCK_SIZE=64);
	on sha1 (data) {
		<<See: http://www.spicynoodles.net/projects/crypto.html
		return (crypto.hashSHA1(data, false))};
	local(k_ipad, k_opad, i);
	if string.length (key) > BLOCK_SIZE {
		key = sha1 (key)};
	for i = 0 to BLOCK_SIZE-1 {
		if i < string.length(key) {
			<<XOR characters of the key
			k_char = string.nthChar(key, i+1);
			k_ipad = k_ipad + char(bit.logicalXor(k_char, char(0x36)));
			k_opad = k_opad + char(bit.logicalXor(k_char, char(0x5c)))}
		else {
			<<Pad out the rest of the block size length
			k_ipad = k_ipad + char(0x36);
			k_opad = k_opad + char(0x5c)}};
	return (sha1 (k_opad + sha1 (k_ipad + data)))}

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This listing is for code that runs in the OPML Editor environment. I created these listings because I wanted the search engines to index it, so that when I want to look up something in my codebase I don't have to use the much slower search functionality in my object database. Dave Winer.