寻找SSH公钥的人…

如果您希望提取用于OpenSSH的公钥，则需要以稍微不同的方式获取公钥

$ ssh-keygen -y -f mykey.pem > mykey.pub

此公钥格式与OpenSSH兼容。将公钥追加到remote:~/。Ssh /authorized_keys，就可以开始了

从SSH-KEYGEN文档(1)

Ssh-keygen -y [-f input_keyfile]

-y该选项将读取私有的OpenSSH格式文件，并将OpenSSH公钥打印到stdout。

在大多数生成RSA私钥的软件中，包括OpenSSL，私钥被表示为PKCS#1 RSAPrivatekey对象或其变体:

A.1.2 RSA private key syntax An RSA private key should be represented with the ASN.1 type RSAPrivateKey: RSAPrivateKey ::= SEQUENCE { version Version, modulus INTEGER, -- n publicExponent INTEGER, -- e privateExponent INTEGER, -- d prime1 INTEGER, -- p prime2 INTEGER, -- q exponent1 INTEGER, -- d mod (p-1) exponent2 INTEGER, -- d mod (q-1) coefficient INTEGER, -- (inverse of q) mod p otherPrimeInfos OtherPrimeInfos OPTIONAL }

正如您所看到的，这种格式有许多字段，包括模数和公共指数，因此是RSA公钥信息的严格超集。

在这段代码中，我们首先创建的是RSA密钥，它是私有的，但它也有一对公钥，所以要获得实际的公钥，我们只需这样做

openssl rsa -in mykey.pem -pubout > mykey.pub

希望你得到更多的信息检查这个

公钥并不像某些人认为的那样存储在PEM文件中。私钥文件上的DER结构如下:

Openssl rsa -text -in mykey.pem

RSAPrivateKey ::= SEQUENCE {
  version           Version,
  modulus           INTEGER,  -- n
  publicExponent    INTEGER,  -- e
  privateExponent   INTEGER,  -- d
  prime1            INTEGER,  -- p
  prime2            INTEGER,  -- q
  exponent1         INTEGER,  -- d mod (p-1)
  exponent2         INTEGER,  -- d mod (q-1)
  coefficient       INTEGER,  -- (inverse of q) mod p
  otherPrimeInfos   OtherPrimeInfos OPTIONAL
}

因此，有足够的数据来计算公钥(模量和公共指数)，这就是openssl rsa -in mykey。Pem -pubout可以

我下面的回答有点长，但希望它能提供一些以前的回答中所缺少的细节。我将从一些相关的陈述开始，最后回答最初的问题。

要使用RSA算法加密东西，你需要模和加密(公共)指数对(n, e)，这是你的公钥。要用RSA算法解密你需要模和解密(私有)指数对(n, d)这是你的私钥。

要使用RSA公钥加密某些内容，您可以将明文作为一个数字，并将其提高到e模n的幂:

ciphertext = ( plaintext^e ) mod n

要使用RSA私钥解密某些内容，您可以将密文视为一个数字，并将其提高到d模n的幂:

plaintext = ( ciphertext^d ) mod n

使用openssl生成私钥(d,n)可以使用以下命令:

openssl genrsa -out private.pem 1024

使用openssl从私钥生成公钥(e,n)，可以使用以下命令:

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

来剖析私人的内容。pem由openssl命令生成的RSA私钥，执行以下命令(这里的输出被截断为标签):

openssl rsa -in private.pem -text -noout | less

modulus         - n
privateExponent - d
publicExponent  - e
prime1          - p
prime2          - q
exponent1       - d mod (p-1)
exponent2       - d mod (q-1)
coefficient     - (q^-1) mod p

Shouldn't private key consist of (n, d) pair only? Why are there 6 extra components? It contains e (public exponent) so that public RSA key can be generated/extracted/derived from the private.pem private RSA key. The rest 5 components are there to speed up the decryption process. It turns out that by pre-computing and storing those 5 values it is possible to speed the RSA decryption by the factor of 4. Decryption will work without those 5 components, but it can be done faster if you have them handy. The speeding up algorithm is based on the Chinese Remainder Theorem.

是的,私人。pem RSA私钥实际上包含这8个值;在运行上一个命令时，它们都不会动态生成。尝试运行以下命令并比较输出结果:

# Convert the key from PEM to DER (binary) format
openssl rsa -in private.pem -outform der -out private.der

# Print private.der private key contents as binary stream
xxd -p private.der

# Now compare the output of the above command with output 
# of the earlier openssl command that outputs private key
# components. If you stare at both outputs long enough
# you should be able to confirm that all components are
# indeed lurking somewhere in the binary stream
openssl rsa -in private.pem -text -noout | less

这种RSA私钥结构被PKCS#1 v1.5推荐为一种替代(第二种)表示。PKCS#1 v2.0标准将e和d指数完全排除在替代表示中。PKCS#1 v2.1和v2.2通过可选地包括更多与crt相关的组件，提出了对替代表示的进一步更改。

公开查看内容。pem public RSA key执行如下命令(此处输出截断为标签):

openssl rsa -in public.pem -text -pubin -noout

Modulus             - n
Exponent (public)   - e

这里没有惊喜。就像之前说的，是(n, e)对。

现在终于回答了最初的问题:如上所示，使用openssl生成的私有RSA密钥包含公钥和私钥的组件，以及其他一些组件。当您从私钥生成/提取/派生公钥时，openssl将其中两个组件(e,n)复制到一个单独的文件中，该文件将成为您的公钥。

使用以下命令:

openssl req -x509 -nodes -days 365 -sha256 -newkey rsa:2048 -keyout mycert.pem -out mycert.pem Loading 'screen' into random state - done Generating a 2048 bit RSA private key .............+++ ..................................................................................................................................................................+++ writing new private key to 'mycert.pem' ----- You are about to be asked to enter information that will be incorporated into your certificate request. What you are about to enter is what is called a Distinguished Name or a DN. There are quite a few fields but you can leave some blank For some fields there will be a default value, If you enter '.', the field will be left blank. If you check there will be a file created by the name : mycert.pem openssl rsa -in mycert.pem -pubout > mykey.txt writing RSA key If you check the same file location a new public key mykey.txt has been created.