公共RSA密钥末尾的用户名和主机名有什么用处

Question

目的是什么：

username@hostname

在RSA公钥的末尾？我知道它与密钥的生成器匹配，但它是否曾用于任何重要的东西？

Answer 1

这只是一个评论，可以帮助您保持每个公钥的来源。

在openSSH源代码中（v6.3，auth-rsa.c：57-65）：

/*
 * The .ssh/authorized_keys file contains public keys, one per line, in the
 * following format:
 *   options bits e n comment
 * where bits, e and n are decimal numbers,
 * and comment is any string of characters up to newline.  The maximum
 * length of a line is SSH_MAX_PUBKEY_BYTES characters.  See sshd(8) for a
 * description of the options.
 */

阅读：

    case KEY_RSA1:
            /* Get number of bits. */
            if (*cp < '0' || *cp > '9')
                    return -1;      /* Bad bit count... */
            for (bits = 0; *cp >= '0' && *cp <= '9'; cp++)
                    bits = 10 * bits + *cp - '0';
            if (bits == 0)  
                    return -1;
            *cpp = cp;
            /* Get public exponent, public modulus. */
            if (!read_bignum(cpp, ret->rsa->e))
                    return -1;
            if (!read_bignum(cpp, ret->rsa->n))
                    return -1;
            /* validate the claimed number of bits */
            if ((u_int)BN_num_bits(ret->rsa->n) != bits) {
                    verbose("key_read: claimed key size %d does not match "
                       "actual %d", bits, BN_num_bits(ret->rsa->n));
                    return -1;
            }
            success = 1;
            break;

它甚至不解析评论。