ssl certificates, etc. Format Description
crt /key /req /csr /pem /der
Certificates with private keys PKCS12 (P12)
contains the form of a certificate of public and private key binary format, as the certificate to pfx file extension.
Binary-coded certificate (DER)
certificate without the private key, certificate DER encoded binary file format to the certificate as a .cer file extension.
Base64-encoded certificate (PEM)
certificate without the private key, certificate file Base64 encoded format, but also as a certificate to .cer file extension.
.crt certificate represents, .key represents the private key, .req express request file, .csr also said that requests a file,
.pem represent pem format, .der expressed der format.
Filename extension you can easily name. Just to understand the need to expand named after a different name. However, there is information in the file format, and exe, PE formats, certificate two formats.
pem format and der format. All certificates, private keys and so can be pem, it can also be der format, depending on the application needs.
pem and der format system conversion:
openssl x509 -in ca.crt -outform THE -out ca.der // pem -> the
openssl x509 -in the -inform ca.der -out ca.pem // the -> pem
pem format: encrypted text file, usually there are several beginning of the end the following:
----- BEGIN RSA PRIVATE KEY -----
----- END RSA PRIVATE KEY -----
or:
--- the CERTIFICATE REQUEST ----- --BEGIN
----- END the CERTIFICATE REQUEST -----
or:
---- BEGIN the CERTIFICATE -----
----- END the CERTIFICATE -----
der format: encrypted binary file.
The public key certificate contains the applicant organization and personal information of the applicant, information agencies issuing CA, the plaintext message valid time, the certificate serial number, etc., and include a signature.
View certificate command:
OpenSSL X509 -noout -text -IN baiducom.crt
reference:
https://www.jianshu.com/p/bad8a99de24c
https://www.cnblogs.com/dinglin1/p/9279831.html
https://www.iteye.com/blog/iluoxuan-1736275
https://www.cnblogs.com/goOtter/p/10255676.html