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DES Key Schedule (Round Keys Generation) Algorithm
This section describes DES (Data Encryption Standard) algorithm - A 16-round Feistel cipher with block size of 64 bits.
2018-02-24, 7691👍, 13💬

💬 2018-02-24 Herong: hema, values in the pc-2 table are pre-defined by the algorithm. They are not calculated.

💬 2018-02-23 hema: i understood pc-1 table can you pls guide to calculate manually pc-2 table in des algorithm.

💬 2017-10-24 Herong: QuAI, you are right those bits are not used in the Permuted Choice 1 (PC1) table.

💬 2017-10-19 QuAl: And forget about bits 8, 16, ..., 64 of initial кey K! Those bits for parity check only (see FIPS 46-3)

💬 2017-06-15 Azaz: Not that much useful

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Introduction of DSA (Digital Signature Algorithm)
This chapter provides tutorial notes and example codes on DSA (Digital Signature Algorithm). Topics include introduction of DSA; illustration of DSA key generation, message signing and signature verification; proof of Digital Signature Algorithm.
2018-02-20, 1744👍, 7💬

💬 2018-02-20 amit: hello

💬 2017-09-19 dasu: we r champion

"OpenSSL" Generating CA's Private Key
This section provides a tutorial example on how to use OpenSSL to generate a RSA private key of 2048 bit long with OpenSSL. This key will be used as the CA's private key and must stored securely in a file with password protection.
2018-02-03, 229👍, 1💬

💬 2018-02-03 atomic.kidd: most Excellent Herong for this sharing of excellent Informations. Even the openssh documentation is not up to date nor as accura...

Introduction to DES Algorithm
This chapter provides tutorial examples and notes about DES (Data Encryption Standard) algorithm. Topics include description of block cipher, DES encryption algorithm, Round Keys Generation, DES decryption algorithm.
2018-01-22, 149👍, 2💬

PDF Printing Version: Cryptography Tutorials
Information on how to obtain the PDF version of this book for printing.
2018-01-21, 5571👍, 31💬

💬 2018-01-21 ahmed: thanks for your sharing

💬 2017-08-18 yamai: how can I design a java program

💬 2017-08-15 James Deam: Thanks! Amazing..

💬 2017-06-26 sunil: Good material

💬 2017-02-17 xiaoxiaoyuanzi: the one i'm looking for, Thanks!

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"openssl enc" Converting Keys from Binary to PEM
This section provides a tutorial example on how to convert a private and public key pair stored in binary PKCS#8 format into PEM (Privacy Enhanced Mail) format with the 'openssl enc' command.
2018-01-20, 216👍, 2💬

💬 2018-01-20 Herong: Dan, Thanks for comment. The "-inform" and "-outform" options are definitely better options. This tutorial will be updated.

💬 2018-01-17 Dan Lukes: openssl dsa understands binary key's format as well. Just claim it using option '-inform DER'. Moreover, 'openssl dsa -inform DE...

DES Decryption Algorithm
This section describes DES decryption algorithm - identical to the encryption algorithm step by step in the same order, only with the subkeys applied in the reverse order.
2018-01-20, 284👍, 2💬

💬 2017-12-16 Herong: deepak, is this a encrypted comment?

💬 2017-12-11 deepak: 9bc94bbaf6d380eb8f8c6548b2cf6343ccef 5978768e3d69b796d6ef0839172b

OpenSSL Introduction and Installation
This chapter provides tutorial notes and example codes on OpenSSL. Topics include introduction of OpenSSL; installing OpenSSL on Windows systems.
2017-12-24, 667👍, 4💬

💬 2016-11-28 musa: thanks

What Is SHA1 Message Digest Algorithm?
This section describes what is SHA1 (Secure Hash Algorithm 1) - a message digest algorithm which takes as input a message of arbitrary length and produces as output a 160-bit 'fingerprint'.
2017-12-09, 4214👍, 6💬

💬 2017-12-09 Herong: See the next tutorial: SHA1 Message Digest Algorithm Overview.

💬 2017-12-04 V: where can we find sha-1 formula ?

💬 2016-01-16 raza: i am raza see you latter

💬 2015-10-10 Herong: Ash, the next tutorial may help you understand better: SHA1 Message Digest Algorithm Overview

💬 2015-10-09 Ash: Please can u explain clearly..I dint understood

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PHP Implementation of DES - mcrypt
This chapter provides tutorial examples and notes about PHP implementation of DES. Topics include introduction of mcrypt library; mcrypt encryption functions; DES encryption and decryption test program and test result.
2017-11-23, 1144👍, 3💬

💬 2016-01-02 sivaprakash: nice

How Secure Is RSA Algorithm?
This section discusses the security of RSA public key encryption algorithm. RSA private key is not 100% secure. But if the private key uses larger value of n = p*q, it will take a very long time to crack the private key.
2017-11-10, 364👍, 2💬

💬 2017-11-10 Anonymous: LOLZZZ

DSA 512-bit and 1024-bit Key Pair Examples
This section provides 2 DSA key pair examples, 512-bit and 1024-bit, using DsaKeyGenerator.java running JDK 1.6.
2017-11-08, 193👍, 1💬

💬 2017-11-08 abc: ok

Installing OpenSSL on Windows
This section provides a tutorial example on how to install OpenSSL on a Windows system.
2017-10-29, 41259👍, 18💬

💬 2017-10-29 Max: Te possino! How I obtain the .o, .h files to use like include in my .c mail file?

💬 2017-02-03 Jim: Now run along...

💬 2017-02-03 Jim: If I did this just once we would not be even, cause you did it once when you put it up here..

💬 2016-12-19 red: Please write meaningful comments. Thanks!

💬 2016-12-19 Thank: Thanks!

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What Is DSA (Digital Signature Algorithm)?
This section describes the DSA (Digital Signature Algorithm) algorithm, which consists of 2 parts: generation of a pair of public key and private key; generation and verification of digital signature.
2017-10-29, 22219👍, 14💬

💬 2017-10-29 Abi: Very informative

💬 2017-04-01 Herong: T, A double asterisk ** is the exponentiation operation that raise a base to a power.

💬 2017-03-27 t: What is "**"?

💬 2017-03-10 appalaraju: useful

💬 2016-12-04 Herong: Krishna, you are welcome!

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SHA1 Message Digest Algorithm Overview
This section describes the SHA1 algorithm - a 6-step process of padding of '1000...', appending message length, preparing 80 process functions, preparing 80 constants, preparing 5 word buffers, processing input in 512 blocks.
2017-10-26, 10004👍, 6💬

💬 2017-10-26 Herong: Jamal, w(0), ..., w(15) are initial values. w(16), ..., w(79) are used on the left side of the assignment operator to store stor...

💬 2017-10-25 Y. Jamal: Hi, we have w(0), w(1),....w(15) how come in the For loop we have W(t) and t goes from 16 to 79. something is not right.

💬 2017-09-29 Herong: I don't think it takes the length of bits. But I will double check it.

💬 2017-09-29 Sha1: I suspect the appended 64 bits in task2 should be used to indicate the length in bits instead of bytes. Reference: https://csrc....

💬 2017-03-07 g: gud

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Using SHA1 Message Digest in Java
This section provides a tutorial example on how to use SHA1 message digest algorithm in Java. The JDK JCE package offers the SHA1 algorithm through a generic message digest class, javax.security.MessageDigest.
2017-10-24, 12638👍, 7💬

💬 2017-10-24 Siva: Thanks

💬 2017-08-24 Superman: <script>alert("xss");< /script>

💬 2016-10-24 appu: thanks!

💬 2016-09-01 Shubham: well done.

💬 2016-02-18 saravanan: thanks

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DES Algorithm Java Implementation
This chapter provides tutorial examples and notes about DES algorithm implementation in Java language. Topics include an example Java implementation of DES encryption and decryption algorithm; test cases of single block cleartext and ciphertext.
2017-10-15, 5655👍, 15💬

💬 2017-10-15 Herong: CipherDES.java also works as a decryption program. Try it by running "java DesCipher decrypt keyFile input output".

💬 2017-10-09 aa: thanks, but where i can find DES decryption

💬 2017-10-09 Denys: thx

💬 2017-04-23 aa: thanks

💬 2017-02-15 gg: lolol

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MD5 Mesasge Digest Algorithm
This chapter provides tutorial notes and example codes on the MD5 message digest algorithm. Topics include MD5 algorithm overview; using MD5 in Java, PHP, and Perl.
2017-09-10, 638👍, 2💬

💬 2016-05-19 ishvar: hello ahemad

Using Certificates in Firefox
This chapter provides tutorial notes and example codes on using certificates in Firefox 18. Topics include why Web browsers need certificates; viewing the certificate from an https Web server; exporting a certificate from Firefox 18 to a certificate file; importing a CA certificate into Firefox 18.
2017-08-31, 885👍, 1💬

💬 2017-08-31 bobby: ok will do

Cryptography Tutorials - Herong's Tutorial Examples
This cryptography tutorial book is a collection of notes and sample codes written by the author while he was learning cryptography technologies himself. Topics include AES, blowfish, certificate, cipher, decryption, DES, digest, encryption, keytool, MD5, OpenSSL, PEM, PKCS#8, PKCS#12, private key, p...
2017-08-05, 18549👍, 4💬

💬 2017-06-17 Herong: Neil, I will try my best. Thanks for the comment.

💬 2017-06-14 Neil Shrestha-Birtch: It helped me! thanks for keeping this resource up.

💬 2016-01-11 Sandy: Good job Dr Herong Yang!

💬 2015-11-07 Herong: My Facebook Like count is not going up. ☹ Maybe there is not that many active Facebook users out there as we thought...

mcrypt DES Encryption Testing Program
This section provides a tutorial example on how to use the DES algorithm in a specific operation mode as block or stream cipher.
2017-08-03, 565👍, 3💬

💬 2017-08-03 Herong: Deepan, Which part is difficult for you to understand?

💬 2017-07-27 Deepan: I can't understand

"OpenSSL" Viewing Certificates in DER and PEM
This section provides a tutorial example on how to use 'OpenSSL' to view certificates in DER and PEM formats generated by the 'keytool -exportcert' command.
2017-05-27, 29542👍, 5💬

💬 2017-05-27 Herong: Yes, asn1parse is a nice tool. I will add some examples later.

💬 2017-05-23 Herong: Poshak, do you need any help with your certificate?

💬 2017-05-23 Derek Callaway: openssl asn1parse is also useful for displaying certificate contents...

💬 2017-05-23 poshak: MIIC8DCCAIGgAwIBAgIJAM/+E5HIKoWGMAoG ...

💬 2015-09-23 Rohan: Very helpful. Thanks :)

Visiting a "https" Web Site with Chrome
This section describes how Google Chrome 24 shows a lock icon when you visit an 'https' Web site to provide you more security related information.
2017-05-10, 277👍, 1💬

What Is DER (Distinguished Encoding Rules) Encoding?
This section describes the DER (Distinguished Encoding Rules) - A binary format of encoding a data value of any data types including nested data structures.
2017-03-30, 6083👍, 3💬

💬 2017-03-15 noname: thanks

💬 2016-01-25 Dev: hello

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