Question

我一直在尝试加密Swift中的字符串，但是我想让它在linux下工作。以下代码（取自these questions的答案不起作用，因为它们依赖于iOS或OSx库：

func sha256(data : Data) -> Data {
    var hash = [UInt8](repeating: 0,  count: Int(CC_SHA256_DIGEST_LENGTH))
    data.withUnsafeBytes {
        _ = CC_SHA256($0, CC_LONG(data.count), &hash)
    }
    return Data(bytes: hash)
}

如何在linux中使用Glibc来完成？

Answer 1

glibc中有一个地穴库，see manpage 您需要包含：#include <crypt.h>。

您必须使用的功能是：

char *crypt(const char *key, const char *salt);

根据该联机帮助页，SHA-256算法已经集成，因为glibc 2.7是通过salt参数选择的：

The glibc2 version of this function supports additional encryption
algorithms.

If salt is a character string starting with the characters "$id$"
followed by a string terminated by "$":

       $id$salt$encrypted

then instead of using the DES machine, id identifies the encryption
method used and this then determines how the rest of the password
string is interpreted.  The following values of id are supported:

       ID  | Method
       ─────────────────────────────────────────────────────────
       1   | MD5
       2a  | Blowfish (not in mainline glibc; added in some
           | Linux distributions)
       5   | SHA-256 (since glibc 2.7)
       6   | SHA-512 (since glibc 2.7)

So $5$salt$encrypted is an SHA-256 encoded password and
$6$salt$encrypted is an SHA-512 encoded one.

"salt" stands for the up to 16 characters following "$id$" in the
salt.  The encrypted part of the password string is the actual
computed password.  The size of this string is fixed:

MD5     | 22 characters
SHA-256 | 43 characters
SHA-512 | 86 characters

The characters in "salt" and "encrypted" are drawn from the set
[a-zA-Z0-9./].  In the MD5 and SHA implementations the entire key is
significant (instead of only the first 8 bytes in DES).

在this official GNU page和this wikipedia article上有解释和示例：

SHA-256的示例salt参数：
$5$9ks3nNEqv31FX.F$gdEoLFsCRsn/WRN3wxUnzfeZLoooVlzeF4WjLomTRFD

使用Glibc的哈希函数

1 个答案: