生成，签名和validation数字证书

所以这是我的项目中的一个问题。

In this task, we will use OpenSSL to generate digital signatures. Please prepare a file (example.txt) of any size. Also prepare an RSA public/private key pair. Then do the following: 1. Sign the SHA256 hash of example.txt; save the output in example.sha256. 2. Verify the digital signature in example.sha256. 3. Slightly modify example.txt, and verify the digital signature again. Please describe how you performed the above three operations (eg, the exact commands that you used, etc.). Describe what you observed and explain your observations. Please also explain why digital signatures are useful in general. 

所以，我做了以下几点。

1.创建私钥/公钥对

 openssl genrsa -out private.pem 1024 

2.提取公钥。

 openssl rsa -in private.pem -out public.pem -outform PEM -pubout 

3.创建数据的哈希值。

 echo 'data to sign' > example.txt openssl dgst -sha256  hash 

4.使用私钥将哈希签名到名为example.sha256的文件

 openssl rsautl -sign -inkey private.pem -keyform PEM -in hash > example.sha256 

5.validation文件（example.txt）和数字签名（example.sha256）

 openssl dgst -sha256 -verify public.pem -signature example.sha256 example.txt 

完成所有这些后，我收到一条错误消息“ validation失败 ”

如果我在某个地方出错，请纠正我。

Answer 1

生成私钥/公钥对。
 1. openssl genrsa -out private.pem 1024
 2. openssl rsa -in private.pem -out public.pem -outform PEM -pubout


标志。
 openssl dgst -sha256 -sign private.pem -out SLA.txt.sha256 SLA.txt 

校验
 openssl dgst -sha256 -verify public.pem -signature SLA.txt.sha256 SLA.txt