多种OpenSSL RSA签名方法产生不同的结果 [英] Multiple OpenSSL RSA signing methods produce different results

问题描述

尝试绕过签名并使用/测试各种选项.

Trying to wrap my head around signing and use/test various options.

我可以使用以下命令签名:

I can sign using this command:

openssl dgst -sha256 -sign private_key.pem -binary -out sig_file data_file

但是文档似乎说我也可以使用这种方法

But the documentation seems to say that I can also use this method

openssl dgst -sha256 -binary data_file > hash_file
openssl rsautl -sign -inkey private_key.pem -keyform PEM -in hash_file > sig_file2

但是当我希望它们相同时，签名是不同的.我可能错过了选项中的某些内容，或者我的假设中有其他错误的地方.

But the signatures are different when I'd expect them to be identical. Either I missed something in the options or something else is wrong in my assumptions.

这个问题的真正问题是:有一种方法可以使用命令行选项进行签名，因为我已经具有哈希值并产生与上面的第一个命令相同的签名.

The real question from this issue: Is there a way to sign using command line options given that I already have the hash value and produce a signature that is identical to the first command above.

要添加更多内容，我可以轻松地在代码中重现第一个命令，并且它与上面的第一个命令匹配，这意味着我可以使用首先计算出的哈希值进行签名.

To add more to this, I can reproduce the first command easily in code and it matches the first command above meaning that I can sign with the hash value calculated first.

mdctx = EVP_MD_CTX_create();
EVP_DigestInit_ex(mdctx, EVP_sha256(), NULL);
EVP_DigestUpdate(mdctx, data, len);
EVP_DigestFinal_ex(mdctx, hash, &s);
EVP_MD_CTX_destroy(mdctx);

kfile = fopen64(key_file, "r");
key = PEM_read_RSAPrivateKey(kfile, NULL, NULL, NULL);
fclose(kfile);

*sig = malloc(RSA_size(key));
RSA_sign(NID_sha256, hash, hlen, *sig, siglen, key);

推荐答案

重复:差异在openSSL rsautl和dgst之间
密切相关:
为什么我用OpenSSL和Java生成的RSA-SHA256签名是否不同?
使用C例程和openssl时的签名不同dgst，rsautl命令
使用openssl.exe使用256位RSA密钥对20字节消息进行签名，但不能在代码中使用
交叉复制: https://superuser. com/questions/943972/openssl-pkeyutl-sign-和openssl-rsautl-sign之间的区别是什么

Dupe: Difference between openSSL rsautl and dgst
Closely related:
Why are the RSA-SHA256 signatures I generate with OpenSSL and Java different?
Different signatures when using C routines and openssl dgst, rsautl commands
Signing 20-byte message with 256-bit RSA key working with openssl.exe but not in code
Crossdupe: https://superuser.com/questions/943972/what-is-the-difference-between-openssl-pkeyutl-sign-and-openssl-rsautl-sign

TLDR :针对RSA的dgst -sign执行完整的RSASSA-PKCS1-v1_5:对数据进行哈希处理，在ASN.1中对哈希进行编码，填充结果并进行modexp d. rsautl -sign仅执行最后两个，而dgst本身仅执行第一个，因此跳过编码会产生不同的非标准签名. dgst(或您自己的哈希)，然后 pkeyutl -sign ，并带有RSA密钥和-pkeyopt digest:name_of_digest(重要！)，也可以工作并回答您的真实问题.

TLDR: dgst -sign for RSA does the full RSASSA-PKCS1-v1_5: hash the data, encode the hash in ASN.1, pad the result, and modexp d. rsautl -sign does only the last two and dgst by itself only the first, thus skipping the encode producing a different and nonstandard signature. dgst (or your own hash) then pkeyutl -sign with an RSA key and -pkeyopt digest:name_of_digest (important!) also works and answers your real question.

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