openssl_sign(): supplied key param cannot be coerced into a private key

PHP RSA 报错
openssl_sign(): supplied key param cannot be coerced into a private key
原因：
本地测试正常，服务器报错
使用测试数据和测试秘钥，本地和服务器都正常
这种情况说明与PHP和OPENSSL版本无关（已经重新编译过PHP和OPENSSL，浪费好多时间）
解决方式：
http://www.itguai.com/php/a5246028.html
看了这篇文章，终于找到解决方式了，
RSA 的秘钥一般都有固定换行格式，是不是这种情况导致的呢
按照此格式试试，问题竟然顺利解决

私钥

$str='你的私钥（改成一行）';
$str        = chunk_split($str, 64, "\n");
        $key = "-----BEGIN RSA PRIVATE KEY-----\n$str-----END RSA PRIVATE KEY-----\n";
        $signature = '';
        if (openssl_sign($data, $signature, $key, OPENSSL_ALGO_MD5)) {
            echo base64_encode($signature);
        }

公钥

$data='内容';
$str='你的公钥（改成一行）';
$str               = chunk_split($str, 64, "\n");
        $key = "-----BEGIN PUBLIC KEY-----\n$str-----END PUBLIC KEY-----\n";
        $signature = "";
        if (openssl_verify(base64_decode($data), $signature, $key, OPENSSL_ALGO_MD5) == 1) {
            echo $signature;
        }

案例：
http://php.net/manual/en/function.openssl-sign.php 官方案例 改造了一下
官方的公钥私钥格式太标准，所以要改造一下。
因为我们拿到的公钥私钥有可能就是一行的

$data = "Beeeeer is really good.. hic...";
$private_key = <<
$public_key = <<

/
//上面是官方的  改造一下
///
//例如我们拿到的公钥私钥是一行的
//私钥
$str='MIIBOgIBAAJBANDiE2+Xi/WnO+s120NiiJhNyIButVu6zxqlVzz0wy2j4kQVUC4ZRZD80IY+4wIiX2YxKBZKGnd2TtPkcJ/ljkUCAwEAAQJAL151ZeMKHEU2c1qdRKS9sTxCcc2pVwoAGVzRccNX16tfmCf8FjxuM3WmLdsPxYoHrwb1LFNxiNk1MXrxjH3R6QIhAPB7edmcjH4bhMaJBztcbNE1VRCEi/bisAwiPPMq9/2nAiEA3lyc5+f6DEIJh1y6BWkdVULDSM+jpi1XiV/DevxuijMCIQCAEPGqHsF+4v7Jj+3HAgh9PU6otj2nY79nJtCYmvhoHwIgNDePaS4inApN7omp7WdXyhPZhBmulnGDYvEoGJN66d0CIHraI2SvDkQ5CmrzkW5qPaE2oO7BSqAhRZxiYpZFb5CI';
$str        = chunk_split($str, 64, "\n");
$private_key = "-----BEGIN RSA PRIVATE KEY-----\n$str-----END RSA PRIVATE KEY-----\n";

//公钥
$str='MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBANDiE2+Xi/WnO+s120NiiJhNyIButVu6zxqlVzz0wy2j4kQVUC4ZRZD80IY+4wIiX2YxKBZKGnd2TtPkcJ/ljkUCAwEAAQ==';
$str               = chunk_split($str, 64, "\n");
        $public_key = "-----BEGIN PUBLIC KEY-----\n$str-----END PUBLIC KEY-----\n";

$binary_signature = "";

openssl_sign($data, $binary_signature, $private_key, OPENSSL_ALGO_SHA1);

// Check signature
$ok = openssl_verify($data, $binary_signature, $public_key, OPENSSL_ALGO_SHA1);
echo "check #1: ";
if ($ok == 1) {
    echo "signature ok (as it should be)\n";
} elseif ($ok == 0) {
    echo "bad (there's something wrong)\n";
} else {
    echo "ugly, error checking signature\n";
}

$ok = openssl_verify('tampered'.$data, $binary_signature, $public_key, OPENSSL_ALGO_SHA1);
echo "check #2: ";
if ($ok == 1) {
    echo "ERROR: Data has been tampered, but signature is still valid! Argh!\n";
} elseif ($ok == 0) {
    echo "bad signature (as it should be, since data has beent tampered)\n";
} else {
    echo "ugly, error checking signature\n";
}