openssl

What is DSA? DSA is short for Digital Signature Algorithm, an asymmetric digital signature algorithm used primarily for digital signatures and this article will use the openssl dsa utility to demonstrate its use. DSA like RSA can be used for both digital signatures and encryption, but is primarily … [Read more...] about openssl dsa

Use the openssl dgst command and utility to output the hash of a given file. The output will be in hexadecimal, and the default hash function is sha256, although this can be overridden. md5 and sha1 are both common digest functions that are still routinely found in practice and can be specified in … [Read more...] about openssl dgst

The openssl ciphers utility is a tool that will display, list, and check supported ciphers. It can test your environment to help you decide which cipher list is appropriate for your setup. openssl ciphers list To display a verbose listing of all ciphers, run the following command: openssl … [Read more...] about openssl ciphers

The openssl genpkey command is a utility for generating asymmetric private keys. openssl genpkey or genrsa The openssl genpkey utility has superseded the genrsa utility. While the genrsa is still valid and in use today, it is recommended to start using genpkey. genpkey gives you more than just … [Read more...] about openssl genpkey

The openssl smime utility is useful for signing and encrypting S/MIME messages. S/MIME messages can be signed by multiple signers, be encrypted, decrypted, and verified. You can purchase an S/MIME email (user) certificate from almost any public CA (Certification Authority). For this exercise, we … [Read more...] about openssl smime

How to use openssl to encrypt a file with an asymmetric public key: Use the -rsautl option in openssl to encrypt a file using the RSA algorithm asymmetrically. When sharing a secret is not possible or less than ideal, asymmetric encryption is your best solution. First, if you do not already … [Read more...] about openssl encrypt a file