Generate Public Key From Pem File Java

Generate a 2048-bit RSA private key. $ openssl genrsa -out privatekey.pem 2048. Convert private Key to PKCS#8 format (so Java can read it) $ openssl pkcs8 -topk8 -inform PEM -outform DER -in privatekey.pem -out privatekey.der -nocrypt. Output public key portion in DER format (so Java. Next, VerSig needs to import the encoded public key bytes from the file specified as the first command line argument and to convert them to a PublicKey.A PublicKey is needed because that is what the Signature initVerify method requires in order to initialize the Signature object for verification. First, read in the encoded public key bytes.

Recall from the Generate Public and Private Keys step that the public key was placed in a PublicKey object named pub. You can get the encoded key bytes by calling the getEncoded method and then store the encoded bytes in a file. You can name the file whatever you want. Generate a 2048-bit RSA private key. $ openssl genrsa -out privatekey.pem 2048. Convert private Key to PKCS#8 format (so Java can read it) $ openssl pkcs8 -topk8 -inform PEM -outform DER -in privatekey.pem -out privatekey.der -nocrypt. Output public key portion in DER format (so Java can read it). Generate public and private keys # Generate a private key openssl genrsa -out./private.pem 2048 # Generate a public key from a private key openssl rsa -pubout-in private.pem -out./public.pem # Get the fingerprint from the private key openssl rsa -pubout-outform DER -in private.pem openssl md5 -c Create client JKS from pem files. May 08, 2011 Convert the new PKCS#12 file (myapp.p12) to PEM using openssl (openssl.exe is in the bin directory of the Apache installation on Windows). Openssl pkcs12 -in myapp.p12 -out myapp.pem If you’re running Apache on.nix, you’re all set!

Generating a KeyStore and TrustStore

The following sections explain how to create both a KeyStoreand a TrustStore (or import a certificate into an existing TrustStoresuch as the default Logical Host TrustStore in the location:


where <c:JavaCAPS> isthe directory where Java CAPS is installed and <MyDomain> isthe name of your domain. The primary tool used is keytool, but openssl isalso used as a reference for generating pkcs12 KeyStores.

For more information on openssl andavailable downloads, visit the following web site:

http://www.openssl.org.

Creating a KeyStore in JKS Format

This section explains how to create a KeyStore using theJKS format as the database format for both the private key, and theassociated certificate or certificate chain. By default, as specifiedin the java.security file, keytool usesJKS as the format of the key and certificate databases (KeyStore andTrustStores). A CA must sign the certificate signing request (CSR).The CA is therefore trusted by the server-side application to whichthe Adapter is connected.

Note –

Session key generation in php. Itis recommended to use the default KeyStore


where <c:JavaCAPS> isthe directory where Java CAPS is installed and <MyDomain> isthe name of your domain.

To Generate a KeyStore

  1. Perform the following command.


  2. Once prompted, enter the information required to generatea CSR. A sample key generation section follows.


    If the KeyStore password is specified, then the password mustbe provided for the adapter.

  3. Press RETURN when prompted for the key password (thisaction makes the key password the same as the KeyStore password).

    This operation creates a KeyStore file clientkeystore in the current working directory. You must specify a fullyqualified domain for the “first and last name” question.The reason for this use is that some CAs such as VeriSign expect thisproperties to be a fully qualified domain name.

    Thereare CAs that do not require the fully qualified domain, but it isrecommended to use the fully qualified domain name for the sake ofportability. All the other information given must be valid. If theinformation cannot be validated, a CA such as VeriSign does not signa generated CSR for this entry.

    This KeyStore containsan entry with an alias of client.This entry consists of the generated private key and information neededfor generating a CSR as follows:


    Online techstream 14 key generator. This command generates a certificate signing request which canbe provided to a CA for a certificate request. The file client.csr contains the CSR in PEM format.

    Some CA (one trusted by the web server to which the adapteris connecting) must sign the CSR. The CA generates a certificate forthe corresponding CSR and signs the certificate with its private key.For more information, visit the following web sites:

    or

    If the certificate is chained with the CA’scertificate, perform step 4; otherwise, perform step 5 in the followinglist:

  4. Perform the following command.


    The command imports the certificate and assumes the client certificateis in the file client.cer and theCA’s certificate is in the file CARoot.cer.

  5. Perform the following command to import the CA’scertificate into the KeyStore for chaining with the client’scertificate.


  6. Perform the following command to import the client’scertificate signed by the CA whose certificate was imported in thepreceding step.


    The generated file clientkeystore containsthe client’s private key and the associated certificate chainused for client authentication and signing. The KeyStore and/or clientkeystore, can then be used as the adapter’sKeyStore.

Public

Creating a KeyStore in PKCS12 Format

This section explains how to create a PKCS12 KeyStoreto work with JSSE. In a real working environment, a customer couldalready have an existing private key and certificate (signed by aknown CA). In this case, JKS format cannot be used, because it doesnot allow the user to import/export the private key through keytool. It is necessary to generate a PKCS12database consisting of the private key and its certificate.

The generated PKCS12 database can then be used as the Adapter’sKeyStore. The keytool utility iscurrently lacking the ability to write to a PKCS12 database. However,it can read from a PKCS12 database.

Note –

There are additional third-party tools available for generatingPKCS12 certificates, if you want to use a different tool.

For the following example, openssl isused to generate the PKCS12 KeyStore:


The existing key is in the file mykey.pem.txt in PEM format. The certificate is in mycertificate.pem.txt, which is also in PEM format. A textfile must be created which contains the key followed by the certificateas follows:


This command prompts the user for a password. The password isrequired. The KeyStore fails to work with JSSE without a password.This password must also be supplied as the password for the Adapter’sKeyStore password.

This command also uses the openssl pkcs12 commandto generate a PKCS12 KeyStore with the private key and certificate.The generated KeyStore is mykeystore.pkcs12 withan entry specified by the myAlias alias.This entry contains the private key and the certificate provided bythe -in argument. The noiter and nomaciter optionsmust be specified to allow the generated KeyStore to be recognizedproperly by JSSE.

Creating a TrustStore

For demonstration purposes, suppose you have the followingCAs that you trust: firstCA.cert, secondCA.cert,thirdCA.cert, located in the directory C:cascerts. You can create a new TrustStore consistingof these three trusted certificates.

To Create a New TrustStore

  1. Perform the following command.


  2. Enter this command two more times, but for the secondand third entries, substitute secondCA and thirdCA for firstCA.Each of these command entries has the following purposes:

    • The first entry creates a KeyStore file named myTrustStore in the current working directoryand imports the firstCA certificateinto the TrustStore with an alias of firstCA.The format of myTrustStore is JKS.

    • For the second entry, substitute secondCA to import the secondCA certificateinto the TrustStore, myTrustStore.

    • For the third entry, substitute thirdCA to import the thirdCA certificateinto the TrustStore.

    Once completed, myTrustStore is available to be used as theTrustStore for the adapter.

To Create a CSR with keytool and Generate a SignedCertificate for the Certificate Signing Request

Get Public Key From Pem File Java

  1. Perform the following operations from the command line.


  2. Generate the Certificate Signing Request.


  3. Generate a signed certificate for the associated Certificate SigningRequest.


  4. Use the keytool to import the CA certificate into the client keystore.


  5. Use the keytool to import the signed certificate for the associatedclient alias in the keystore.


    Caution –

    The following error will be generated if there is no certificatechain in the client certificate.


    This error is because the CA’s certificate was not imported intothe KeyStore first. You must import theCA's certificate (step 4), then import the client.cer file itself to forma certificate chain (step 5).

    Now that we have a private key and an associating certificate chainin the KeyStore clientkeystore, we canuse it as a KeyStore for client (adapter)authentication. The only warning is that the CA certificate must be importedinto the trusted certificate store of the web server to which you will beconnecting. Moreover, the web server must be configured for client authentication(httpd.conf for Apache, for example).