OpenSSL encryption and decryption

I. Preface

OpenSSL is an open-source software library package that implements SSL and TLS protocols. Its main library is written in C language and implements basic encryption functions.

OpenSSL can run on most Unix-like operating systems (including Solaris, Linux, Mac OS X, and various open-source BSD operating systems), OpenVMS, and Microsoft Windows. It also provides a portable version that can run on IBM I (OS/400.

OpenSSL consists of three parts: libcryto, a general-purpose encryption library, which implements a large number of encryption libraries, libssl, and SSL. is used to implement TLS/SSL functions, OpenSSL is the third, is a multi-functional command line tool, it can implement encryption and decryption, and even can be used as a ca, you can create a certificate, revoke the certificate.

Ii. Encryption type:

There are two types of encryption: symmetric encryption and asymmetric encryption.

Here we mainly study asymmetric encryption:

[[Email protected] ~] # Cp/etc/fstab./# copy the file to the current directory [[email protected] ~] # Lsanaconda-ks.cfg fstab install. Log install. log. syslog [[email protected] ~] # Cat fstab # view the file #/etc/fstab # Created by Anaconda on Fri Dec 26 18:09:56 2014 # accessible filesystems, by reference, are maintained under '/dev/disk' # See man pages fstab (5), findfs (8), Mount (8) and/or blkid (8) for more info #/dev/mapper/vg_magine3562-lv_root/ext4 defaults 1 1 UUID = d507dc4f-dcaa-4311-9aa6-3392322b064c/boot ext4 defaults 1 2/dev/mapper/vg_magine3562-lv_home/home ext4 defaults 1 2/dev/mapper/vg_magine3562-lv_swap swap defaults 0 0 tmpfs/dev/SHM tmpfs defaults 0 0 devpts/dev/PTS devpts gid = 5, mode = 620 0 0 sysfs/sys sysfs defaults 0 0 proc/proc defaults 0 0 [[email protected] ~] # OpenSSL ENC-des3-In fstab-e-out fstab. des3 # encryption enter des-ede3-cbc encryption password: # encryption password verifying-enter des-ede3-cbc encryption password: # enter the password again [[email protected] ~] # The lsanaconda-ks.cfg fstab. des3 install. Log install. log. syslog [[email protected] ~] # Cat fstab. des3 # view the encrypted file. O... frame. M. K folder ??.? [?? .?. JD play y? Limit two E19 ?)?. Shan ai +? Poly. ug? Zieh ??!.?? G? Y? 6? Q % [email protected]?. Z .. g problems .? Usage: c ..? Commission-?]?. M | .?? Wrong ov .?.. '{.#!? E <[^? * 2 ??. C %4gs % ??? /C> MX5 ??. Ray P? Q ??. Q0te now Q. Is there a bowl of benzene ?? H'tx Jun 8.-s .??.?. Cr! Why? Yi. Q ?.? Z. o6 ?. V ?? W. (too many .;.?? 9? U]?. Why J ?. & U ?? {] O2 ?? I. _ Shuai omitted X ...? A maximum capacity ???. B ,?.. 7 P & H error ?? Q. I *? ".?. UGU 6 .?? V <?. G? G? [+ Sans G? + FN ??.?. Division 9m. g. P ??? "?}? Lian \ Jian K ..??? Cluster -? Q... y .....? E]? S... 1? E. W ?.?.? Rt. ^? V ?. Comment 'U splash ..:.?? Town ?.. Ray! 8? Forbidden. F? :?..?? Wzi ??? Q? Export k5wjk4 .?. La # | = p4jw ?? Tw ?? FD .?).? "?? 5. loose? Listen 7? Why? MX? Zaj + S labels \ vmv0 .??. Why? J? :?.. R .?. Q? V Jin ..? M role? Hkm? B? Parent. {. Role <?. Jue. _ gang _ [[email protected] ~] # OpenSSL ENC-des3-In fstab. des3-D-out fstab1 # decrypt enter des-ede3-cbc decryption password: # enter the password for encryption [[email protected] ~] # Cat fstab1 # view decrypted files #/etc/fstab # Created by Anaconda on Fri Dec 26 18:09:56 2014 # accessible filesystems, by reference, are maintained under '/dev/disk' # See man pages fstab (5), findfs (8), Mount (8) and/or blkid (8) for more info #/dev/mapper/vg_magine3562-lv_root/ext4 defaults 1 1 UUID = d507dc4f-dcaa-4311-9aa6-3392322b064c/boot ext4 defaults 1 2/dev/mapper/vg_magine3562-lv_home/home ext4 defaults 1 2/dev/mapper /vg_magine3562-lv_swap swap defaults 0 0 tmpfs/dev/SHM tmpfs defaults 0 0 devpts/dev/PTS devpts gid = 5, mode = 620 0 0 sysfs/sys sysfs defaults 0 0 proc/proc defaults 0 0

Iii. unidirectional encryption

One-way encryption (also called hash algorithm) if no data fingerprint is generated, it is also called the data digest algorithm, the output is fixed length, the MD5 is 128-Bit fixed-length output, and the sha1 fixed-length output is 160-bit, its feature is not collision every data, as long as there is a difference, will produce a huge change, we call this as an avalanche effect, commonly used algorithms MD5, sha1, sha512, commonly used tools include sha2sum, md5sum, cksum, openSSL DGST.

[[Email protected] ~] # OpenSSL DGST-MD5-hex fstab # extract the signature MD5 (fstab) = 653db83e6cdb396784a60b6ee2f9c2aa [[email protected] ~] # Same as the md5sum fstab # algorithm, the result will also be the same as 653db83e6cdb396784a60b6ee2f9c2aa fstab

OpenSSL encryption and decryption