c - 在C的OpenSSL中以DER格式打印DH参数

有没有办法从OpenSSL的DH结构中打印DH参数？

最佳答案

用户dave_thompson_085基本上在his comment中给了您答案。对于您正在使用的版本，函数i2d_DHparams_fp()不可用，您必须使用i2d_DHparams()来获取未签名字符的缓冲区，然后将其写入文件。像这样的东西。

/* Just an example */
DH *dh = DH_get_2048_256();
unsigned char *der = NULL;

/* On success, len contains the length of the buffer */
int len = i2d_DHparams(dh, &der);

/* Open file, write bytes to it, close file */
FILE *fder = fopen("dhparams.der", "wb");
fwrite(der, len, 1, fder);
fclose(fder);

/* Done with the buffer */
OPENSSL_free(der);

必须添加错误检查。
您可以使用asn1parse工具检查它是否工作，如下所示：

$ openssl asn1parse -inform der -in dhparams.der
    0:d=0  hl=4 l= 521 cons: SEQUENCE
    4:d=1  hl=4 l= 257 prim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
  265:d=1  hl=4 l= 256 prim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