php What is the use of the php_openssl.dll file?

This article is a detailed analysis and introduction to the role of php_openssl.dll in php. Friends who need it can refer to it

一.opensslIntroduction
Data encryption is an important part of information transmission. It is indeed a very unsafe practice to transmit any information in plain text. Therefore,
needs to encrypt the data. The plain text The data is converted into ciphertext data and then transmitted.

OpenSSL is a set of encryption tools for the SSL/TLS protocol. Its functions are:
1. Generate a private key.
2. Generate a certificate, that is, a digital signature certificate, which contains a public key that can be used to encrypt and decrypt data in one direction. That is, data encrypted using the public key can only be decrypted using the
private key. .Data encrypted using the private key can be decrypted using the public key.
3. Calculation informationSummary.
4.SSL/TLS client and server side testing.
5. Handle the encryption of S/MIME tags and emails.

2. Introduction to encryption technology.
Encryption is the process of converting plaintext data into ciphertext data. To keep the plain text confidential.
Encryption algorithm: An algorithm used in the data encryption process. It is used to convert plain text into cipher text.
Key: The encryption algorithm uses a certain method with the key Operation, encrypt the plaintext data to generate encrypted data. When decrypting, the encryption algorithm uses the key to
convert the encrypted data into plaintext data.
In today's encryption technology, the encryption algorithm is public, that is, everyone Everyone knows the calculation method used in encryption. But only by using the key can the ciphertext be decrypted. Therefore, the protection of the key is the core of data security.

3. Introduction to using the openssl tool
1. Private key generation methodTo generate a private key, you can use different digital signature algorithms. The following are introduced separately;

# adopts DSA algorithm

$ openssl dsaparam -noout -out dsakey0.pem -genkey 1024
#Use RSA algorithm
$ openssl genrsa -out rsakey0.pem 1024
#Use RSA algorithm and use password protection. When generating a private key, you need to enter a password to protect the private key.
#You also need to enter this password when using this private key for encryption/decryption operations.
$ openssl genrsa -des3 -out rsakey1 .pem 10242. Public key generation method
Generate public key based on private key
#Generate public key of dsa algorithm
$ openssl dsa -in dsakey0.pem -pubout -out dsakey0-pub.pem
#Generate the public key of the rsa algorithm
$ openssl rsa -in rsakey0.pem -pubout -out rsakey0-pub.pem3. How to generate a self-signed certificate
#Generate the certificate of the DSA algorithm
$ openssl req -x509 -key dsakey0.pem -days 365 -out mycert-dsa.pem -new
#Generate RSA algorithm certificate
$ openssl req -x509 -key rsakey0.pem -days 365 -out mycert- rsa.pem -new


4. Use certificate for email encryption
Our plain text message content:

$ cat test.txt

111111
222222
333333
444444
aaaaaa

Use the certificate to encrypt the plaintext letter and output it to the etest.txt file:
$ openssl smime -encrypt -in test.txt -out etest.txt mycert-rsa.pem View the encrypted ciphertext content:

$ cat etest.txt

MIME-Version: 1.0
Content-Dis
position: attachment; filename="smime.p7m"Content-Type: application/x-pkcs7-mime; smime-type=enveloped-data; name="smime.p7m"
Content-Transfer-Encoding: base64

MIIBYAYJKoZIhvcNAQcDoIIBUTCCAU0CAQAxgewwgekCAQAwUjBFMQswCQYDVQQG

EwJBVTETMBEGA1UECBMKU29tZS1TdGF0ZTEhMB8GA1UEChMYSW50ZXJuZXQgV2lk
Z2l0 cyBQdHkgTHRkAgkAr71mh4NRX/UwDQYJKoZIhvcNAQEBBQAEgYCbrA1WBwQK
Zj7TcNtrxi DzqMBc/Lu063SLKvBK6mQMqT+npFOOFtzIKdFVkldH0YyQhMZDSCyq
YUtGwOaDw6Jn0AHR t64UwPOKoaeL9RVqp9vgtiFC/uXis5UeyZCWS1z7Jsih8Aa+
Da/DQN0sOCX85OdK/TDewNx8mTaYBbVf4jBZBgkqhkiG9w0BBwEwGgYIKoZIhvcN
AwIwDgICAKAAECNxsgiJ2s +1ugDC6JknPL+rDYBCddcyPH+bMYjqrUP0hE/GQ5WSj
sv8CDkOUdvY5XG440yiAL3Z3ysI=Use private key to decrypt and output to dtest.txt file:

$ openssl smime -decrypt -in etest.txt -inkey rsakey0.pem -out dtest .txt View the decrypted letter content, which is completely consistent with the original plain text letter content.

$ cat dtest.txt

111111
222222
333333
444444
aaaaaa


5. Simple file encryption
Plain text file content:

$ cat test.txt

1
22
333
4444
55555
Hello encrypts the plain text file, the output is the test.enc file, enter "123123" as the encryption password:

$ openssl enc -aes-256-cbc -salt -in test.txt -out test.enc

enter aes-256-cbc encryption password:
Verifying - enter aes-256-cbc encryption password: Decrypt the ciphertext, enter "123123" as the decryption password:

$ openssl enc -d -aes-256-cbc -in test.enc
enter aes-256-cbc decryption password:
1
22
333
4444
55555
Hello

6. Simple StringEncryption
Encrypt using base64:

$ echo "encode me" | openssl enc -base64
ZW5jb2RlIG1lCg==When decrypting, you need to know the encryption algorithm before you can decrypt:

$ echo "ZW5jb2RlIG1lCg==" | openssl enc -base64 -d
encode me

7. Testing of SSL client and server
Use the private key and certificate to start the SSL server, the role of "-www" Yes, when the client connects to the server, a status information web page is sent to the client.

openssl s_server -key mykey.pem -cert mycert.pem -www connects the SSL server to the client. The client will obtain the server's certificate:

openssl s_client -connect localhost:4433

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