I've been using OpenSSL a LOT for work lately and I've learned some interesting stuff. Here's a quick guide on how to encrypt and decrypt files using AES in CBC or CTR mode using 256 bit keys and 128 bits IVs. To do this, I used the EVP API in OpenSSL, which allows you to easily encrypt a file using any cipher of your liking.
Evp_cipherinit_ex Segmentation Fault
I am assuming some crypto knowledge here, such as block ciphers, modes of operation, keys, IVs, plaintexts, ciphertexts, etc.There's a great course on Coursera.org on cryptography if you want to learn more about these things.
Evp_cipherinit_ex
So, let's get to it! :) Encrypting or decrypting a file using the EVP API in OpenSSL can be done as follows in C:
Probable bug causes SEGFAULT due to access to pointers in uninitialized EVPCIPHERCTX structure given to EVPCipherInitex function by PKCS5pbe2set function, when using PEMwritePKCS8PrivateKey. Pastebin.com is the number one paste tool since 2002. Pastebin is a website where you can store text online for a set period of time.
This code is part of a little tool I wrote for fun, while waiting for my laundry in Brooklyn, called CryptoManiac. It depends on a couple of things like:
Evp_cipherinit_ex Code
You can download the full C source code from Github.
OpenSSL EVP 関数 概要. EVP (The Digital EnVeloPe library) は，OpenSSL の暗号機能（暗号化・復号，ダイジェスト，署名など）に関する高レベルのインタフェース(API) を提供するライブラリである．暗号機能の実現には，各暗号アルゴリズムに固有の関数群を利用することもできるが，EVP 関数を利用するこ.
Evp_cipherinit_ex Manpage
Enjoy!
Evp_cipherinit_ex Doc
This post used to be at http://alinush.org/2012/08/25/encrypting-a-file-using-aes-in-256-bit-cbcctr-mode-using-the-openssl-library/.
