pem 格式证书 怎么使用openssl

Posted 2023-04-04

参考技术A 命令密钥

$openssl genrsa -out mykey.pem 2048

$openssl pkcs8 -topk8 -inform PEM -outform PEM -in mykey.pem \
-out private_key.pem -nocrypt

命令公共密钥
$ openssl rsa -in mykey.pem -pubout -outform DER -out public_key.der

我写两读取私钥公钥

别public PrivateKey getPemPrivateKey(String filename, String algorithm) throws Exception
File f = new File(filename);
FileInputStream fis = new FileInputStream(f);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int) f.length()];
dis.readFully(keyBytes);
dis.close();

String temp = new String(keyBytes);
String privKeyPEM = temp.replace("-----BEGIN PRIVATE KEY-----\n", "");
privKeyPEM = privKeyPEM.replace("-----END PRIVATE KEY-----", "");
//System.out.println("Private key\n"+privKeyPEM);

Base64 b64 = new Base64();
byte [] decoded = b64.decode(privKeyPEM);

PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(decoded);
KeyFactory kf = KeyFactory.getInstance(algorithm);
return kf.generatePrivate(spec);


public PublicKey getPemPublicKey(String filename, String algorithm) throws Exception
File f = new File(filename);
FileInputStream fis = new FileInputStream(f);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int) f.length()];
dis.readFully(keyBytes);
dis.close();

String temp = new String(keyBytes);
String publicKeyPEM = temp.replace("-----BEGIN PUBLIC KEY-----\n", "");
publicKeyPEM = privKeyPEM.replace("-----END PUBLIC KEY-----", "");

Base64 b64 = new Base64();
byte [] decoded = b64.decode(publicKeyPEM);

X509EncodedKeySpec spec =
new X509EncodedKeySpec(decoded);
KeyFactory kf = KeyFactory.getInstance(algorithm);
return kf.generatePublic(spec);
本回答被提问者采纳

openssl查看pem格式证书细节

openssl x509部分命令

打印出证书的内容：
openssl x509 -in cert.pem -noout -text
打印出证书的系列号
openssl x509 -in cert.pem -noout -serial
打印出证书的拥有者名字
openssl x509 -in cert.pem -noout -subject
以RFC2253规定的格式打印出证书的拥有者名字
openssl x509 -in cert.pem -noout -subject -nameopt RFC2253
在支持UTF8的终端一行过打印出证书的拥有者名字
openssl x509 -in cert.pem -noout -subject -nameopt oneline -nameopt -escmsb
打印出证书的MD5特征参数
openssl x509 -in cert.pem -noout -fingerprint
打印出证书的SHA特征参数
openssl x509 -sha1 -in cert.pem -noout -fingerprint
把PEM格式的证书转化成DER格式
openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
把一个证书转化成CSR
openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
给一个CSR进行处理，颁发字签名证书，增加CA扩展项
openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca -signkey key.pem -out cacert.pem
给一个CSR签名，增加用户证书扩展项
openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr -CA cacert.pem -CAkey key.pem -CAcreateserial