what's the problem with OAuth?

[Wang]

array(7) { ["method"]=> string(4) "POST" ["url"]=> string(54) "https://api.login.yahoo.com/oauth/v2/get_request_token" ["code"]=> int(401) ["requestHeaders"]=> array(2) { [0]=> string(24) "Accept: application/json" [1]=> string(47) "Content-Type: application/x-www-form-urlencoded" } ["requestBody"]=> string(383) "oauth_callback=http%3A%2F%2Fmacmeidasoftware.com%2F~wangchao%2Fyahoo%2Fyahoo.php%3Fin_popup&oauth_consumer_key=dj0yJmk9NkJLcm1yVXBRek1EJmQ9WVdrOWEydHNlRTFKTnpBbWNHbzlOa
kEzTlRreU1qSXomcz1jb25zdW1lcnNlY3JldCZ4PTc5&oauth_nonce=d08dc3f74e5aadc890cf374102b3651b&oauth_signature=J9Lmqdc6DjMBEqHhd%2FTvdBTzQGQ%3D&oauth_signature_method=HMAC-SHA1&oauth_timestamp=1259113893&oauth_version=1.0" ["responseHeaders"]=> array(6) { ["Date"]=> string(29) "Wed, 25 Nov 2009 01:56:44 GMT" ["P3P"]=> string(209) "policyref="http://info.yahoo.com/w3c/p3p.xml", CP="CAO DSP COR CUR ADM DEV TAI PSA PSD IVAi IVDi CONi TELo OTPi OUR DELi SAMi OTRi UNRi PUBi IND PHY ONL UNI PUR FIN COM NAV INT DEM CNT STA POL HEA PRE LOC GOV"" ["WWW-Authenticate"]=> string(37) "OAuth oauth_problem=signature_invalid" ["Connection"]=> string(5) "close" ["Transfer-Encoding"]=> string(7) "chunked" ["Content-Type"]=> string(33) "application/x-www-form-urlencoded" } ["responseBody"]=> string(31) "oauth_problem=signature_invalid" }


oauth_problem=signature_invalid ?????? why ?????

[Jonathan LeBlanc]

Can you please provide the code that you are using?

- Jon