Magento 1.9 Unknown cipher in list: TLSv1
If you have updated Magento to 1.9.2, you may encounter this error when using the downloader. The problem is due to older ciphers and remains an uncorrected bug. But this is fixed by adjusting one line of code.
To correct this, in downloader/lib/Mage/HTTP/Client/Curl.php, change:
$this->curlOption(CURLOPT_SSL_CIPHER_LIST, 'TLSv1'); to $this->curlOption(CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1);