Question

默认情况下，当您生成EVP_PKEY密钥时，它将具有SHA1摘要，可以通过以下代码进行验证：

int def_nid;
EVP_PKEY_get_default_digest_nid(pk, &def_nid);

def_nid将具有值0x64（SHA1）。有没有办法将其配置为SHA256或任何其他摘要算法？

Answer 1

有没有办法将其配置为SHA256或任何其他摘要算法？

没有。根据{{3}}的文档：

For all current standard OpenSSL public key algorithms SHA1 is returned.

如果查看实现，您将看到其硬编码且不可配置：

$ grep -R EVP_PKEY_get_default_digest_nid *
...
crypto/evp/p_lib.c:int EVP_PKEY_get_default_digest_nid(EVP_PKEY *pkey, int *pnid)
...

然后：

int EVP_PKEY_get_default_digest_nid(EVP_PKEY *pkey, int *pnid)
{
    if (!pkey->ameth || !pkey->ameth->pkey_ctrl)
        return -2;
    return pkey->ameth->pkey_ctrl(pkey, ASN1_PKEY_CTRL_DEFAULT_MD_NID,
                                  0, pnid);
}

和

$ grep -R ASN1_PKEY_CTRL_DEFAULT_MD_NID *
crypto/dsa/dsa_ameth.c:     case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
crypto/ec/ec_ameth.c:       case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
crypto/evp/evp.h:#define ASN1_PKEY_CTRL_DEFAULT_MD_NID  0x3
crypto/evp/p_lib.c:    return pkey->ameth->pkey_ctrl(pkey, ASN1_PKEY_CTRL_DEFAULT_MD_NID,
crypto/hmac/hm_ameth.c:     case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
crypto/rsa/rsa_ameth.c:        case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
engines/ccgost/gost_ameth.c:        case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
engines/ccgost/gost_ameth.c:        case ASN1_PKEY_CTRL_DEFAULT_MD_NID:

最后，来自crypto/hmac/hm_ameth.c：

static int hmac_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
{
    switch (op)
    {
        case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
            *(int *)arg2 = NID_sha1;
            return 1;

        default:
            return -2;
    }
}

而且，来自crypto/rsa/rsa_ameth.c：

static int rsa_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
{
    X509_ALGOR *alg = NULL;
    switch (op)
    {
        ... 
        case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
            *(int *)arg2 = NID_sha1;
            return 1;
        ...
}

OpenSSL使用SHA256摘要生成密钥

1 个答案: