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Why are my passphrases different in OpenSSL ENC?
openssl enc -aes-256-cbc -pass pass:MYPASSWORD -P If you run this command several times, you will notice each invocation returns different values ! That’s because, in the absence of the -d flag, openssl enc does encryption and generates a random salt each time. Since the salt varies, so do the key and IV.
How to recover the key and IV in OpenSSL?
The salt is a piece of random bytes generated when encrypting, stored in the file header; upon decryption, the salt is retrieved from the header, and the key and IV are re-computed from the provided password and salt. At the command-line, you can use the -P option (uppercase P) to print the salt, key and IV, and then exit.
Why is the-P FLAG not used in OpenSSL?
That’s because, in the absence of the -d flag, openssl enc does encryption and generates a random salt each time. Since the salt varies, so do the key and IV. Thus, the -P flag is not very useful when encrypting; the -p flag, however, can be used. Let’s try again; this time, we have the file foo_clear which we want to encrypt into foo_enc.
Is it possible to recover a lost passphrase for a?
Just as an example, if you were running Apache, and it had something like this in the httpd.conf file: That means that Apache will run /etc/apache2/getsslpassphrase to get passphrases; and you can do the same: should output the passphrase for the server.example.com key.
How to derive an AES key from OpenSSL?
As mentioned in the other answers, previous versions of openssl used a weak key derivation function to derive an AES encryption key from the password.
How is the key and IV retrieved in OpenSSL?
OpenSSL uses a salted key derivation algorithm. The salt is a piece of random bytes generated when encrypting, stored in the file header; upon decryption, the salt is retrieved from the header, and the key and IV are re-computed from the provided password and salt.
How to create a key from a password in OpenSSL?
When only the key is specified using the -K option, the IV must explicitly be defined. When a password is being specified using one of the other options, the IV is generated from this password. -md digest Use the specified digest to create the key from the passphrase.