Description:
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This patch enables signing and verifying signatures with DSA keys. This currently does not work because EVP_sha1() is called when signing with SHA1 hash, and EVP_dss1() must be called for DSA-SHA1 signing.  It adds the OPENSSL_ALGO_DSS1 constant which must be used with the last parameter of openssl_sign and openssl_verify when using a DSA key.

From the <a href="http://www.die.net/doc/linux/man/man3/evp_digestinit.3.html">man page</a>: "The link between digests and signing algorithms results in a situation where EVP_sha1() must be used with RSA and EVP_dss1() must be used with DSS even though they are identical digests."

Patch available <a href="http://trigse.cx/php-openssl-patch.diff">here</a>.

Reproduce code:
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$key = file_get_contents("keys/dsa.privkey.pem");
$prkeyid = openssl_get_privatekey($key);
$ct = "Hello I am some text!";
openssl_sign($ct, $signature, $prkeyid, OPENSSL_ALGO_DSS1);
echo "Signature: ".base64_encode($signature)."<br>";

$key = file_get_contents("keys/dsa.pubkey.pem");
$pukeyid = openssl_get_publickey($key);
$valid = openssl_verify($ct, $signature, $pukeyid, OPENSSL_ALGO_DSS1);
echo "Signature validity: ".$valid;

Expected result:
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(After patch)
Signature: MCwCFGKwtl03QDikxpqoGMrr4+EPoZfZAhQYIl/Bhzur/CW50b3ZFf5dYig3PA==
Signature validity: 1

Actual result:
--------------
(Before patch)
Signature:
Signature validity: -1