Herong's Tutorial Examples: Cryptography

EC Cryptography Tutorials - Herong's Tutorial Examples
This EC (Elliptic Curve) cryptography tutorial book is a collection of notes and sample codes written by the author while he was learning cryptography technologies himself. Topics include rule of chord and point addition on elliptic curves; Abelian groups with additive and multiplicative notations; ... 2019-01-01, 332👍, 1💬

💬 2019-01-01 Yale: Thank you!

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Converting Secret Keys to and from Byte Arrays
This section provides a quick introduction of the SecretKeySpec class and the KeySpec interface. They can be used to convert secret keys into byte arrays to store them in external files. 2019-04-22, 6781👍, 4💬

💬 2019-04-22 xyz: $9$RTHhSlWL7VsguO7dbw4oiHqf6CuOIRhyl K4JGDq.TQF/OIcyeLXNbsPTz3CAW8X

💬 2018-10-20 Herong: Marco, I just did a Google translation on your comment: "I wonder what all this could be". Are you trying to ask a question?

💬 2018-10-16 Marco: mi chiedo che cosa potrebbe essere tutto questo

💬 2015-11-03 cpp: hello

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. 2019-04-09, 24724👍, 16💬

💬 2019-04-09 ,.mm./,: .,m,

💬 2018-08-29 Shawn: Thanks for the detailed explanation.

💬 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 "**"?

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RSA Private Key and Public Key Pair Sample
This section provides a tutorial example on how to run JcaKeyPair.java to generate a RSA private key and public key pair sample. Keys are stored PKCS#8 and X.509 encoding formats. 2019-04-03, 206👍, 2💬

💬 2019-03-31 Herong: Thong, if you lost access to your BTC wallet, or lost your BTC wallet, then you lost your BTC asset. There is no way to get it b...

💬 2019-03-29 Thong Ngo: Hi . I forgot the id wallet btc, is there any way to find the id wallet btc no? Thanks .

What Is Block Cipher?
This section describes what is block cipher - An encryption scheme in which 'the clear text is broken up into blocks of fixed length, and encrypted one block at a time'. 2019-04-03, 127👍, 2💬

💬 2019-03-31 Herong: Patrick, f() represents a generic block cipher process that convert a block of plaintext into a block of ciphertext with a secre...

💬 2019-03-26 Patrick: if f is a block cipher, then how can f(R0,k1) be performed? f is likely to be something like a function?

RsaKeyValidator.java for RSA Key Validation
This section provides a tutorial example on how to validate RSA keys by encrypting and decrypting some random sample messages. 2019-04-02, 102👍, 1💬

Illustration of DSA Algorithm: p,q=23,11
This section provides a tutorial example to illustrate how DSA digital signature algorithm works with small prime modulus p=23 and prime divisor q=11. 2019-03-25, 129👍, 1💬

java.security.KeyFactory - Reading Encoded Keys
This section describes the java.security.KeyFactory class, which allows you to convert key spec objects back to key objects. Full process of reading and converting encoded key files back to key objects are also provided. 2019-03-23, 139👍, 2💬

💬 2019-03-23 Herong: See the next tutorial "JcaKeyFactoryTest.java - Key Factory Test Program" for code samples.

💬 2019-03-13 wubba lubba dub dub: code samples along with this would've been helpful

Example Vector of AES Encryption
An example vector of AES-128 encryption is presented. Round keys and state values of all 11 rounds are included to help users to verify their AES implementation. 2019-02-24, 158👍, 1💬

"keytool" Exporting Certificates in DER and PEM
This section provides a tutorial example on how to export certificates in DER and PEM format using the 'keytool -exportcert' command. 2019-02-20, 22852👍, 5💬

💬 2019-02-20 Ajay Singh: Ok

💬 2018-10-06 Herong: Srinivas, what are those special characters? Are they appended to the keystore file or the certificate file?

💬 2018-09-25 Srinivas: After generating certificate, there are some special characters appended.

💬 2016-06-27 Herong: Mandar, can you double check your command? The error indicates you entered a wrong password.

💬 2016-06-23 Mandar: converting to der is sucessful. while converting to pem, I am getting below error. keytool error: java.io.IOException: Keystore ...

Cryptography Terminology
This section provides descriptions on some commonly used cryptography terminologies 2019-02-18, 2364👍, 2💬

💬 2019-02-18 Hh: <body bgcolor="red">

💬 2015-10-24 dexter aparicio: this site is my favorite reference on cryptography topics

AES Key Schedule Example
An example of the AES key schedule is provided to illustrate how 11 round keys get calculate from a given 128-bit cipher key. 2019-02-18, 326👍, 1💬

💬 2019-02-18 Ggf: hello

What Is a Digital Signature?
This section describes what is a digital signature and what is the process of generating and verifying digital signature from a message. 2019-01-29, 2670👍, 2💬

💬 2019-01-29 nilo: Hola

💬 2016-04-26 santosh patil: Its easy to understand

Illustration of RSA Algorithm: p,q=5,7
This section provides a tutorial example to illustrate how RSA public key encryption algorithm works with 2 small prime numbers 5 and 7. 2019-01-21, 428👍, 2💬

💬 2019-01-21 Herong: someone, why 35 and 5 must be coprime numbers?

💬 2019-01-16 someone: >Compute n = p*q: n = 5*7 = 35 >Compute m = (p-1)*(q-1): m = 4*6 = 24 >Select e, such that e and m are coprime numbers: e = 5 35...

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. 2018-12-28, 11441👍, 7💬

💬 2018-12-28 '">alert(2): '"><script>alert(1)</s cript>

💬 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....

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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. 2018-12-22, 1691👍, 4💬

💬 2018-12-22 Hari: Hello

💬 2016-01-02 sivaprakash: nice

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. 2018-12-13, 6506👍, 16💬

💬 2018-12-13 syed zia ur rehman: i realy like your link

💬 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

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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. 2018-12-04, 15207👍, 11💬

💬 2018-12-04 Gowtham: Great & Layman Terms

💬 2018-09-12 Onkar D: very good summary about SHA1

💬 2018-09-11 abccc: dvcz

💬 2018-08-31 Munikumar: Great...

💬 2017-10-24 Siva: Thanks

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Outdated: Visiting an "https" Web Site with Firefox 3
This section describes how Firefox 3 shows a lock icon when you visit an 'https' Web site to provide you more security related information. 2018-11-10, 125👍, 2💬

💬 2018-11-10 Herong: Falle, try to use whois.icann.org to get more information about that website.

💬 2018-11-10 Falle: Thanks for your help . I couldn't access full information about cardtopia.org a website that scammed me of apple gift cards wort...

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. 2018-10-29, 8290👍, 4💬

💬 2018-10-29 Thanks!: meaningful comments.

💬 2017-03-15 noname: thanks

💬 2016-01-25 Dev: hello

PDF Printing Version: Cryptography Tutorials
Information on how to obtain the PDF version of this book for printing. 2018-10-20, 6314👍, 34💬

💬 2018-10-20 Herong: bachi, thanks for sharing your comment.

💬 2018-10-13 bachi: I like how you composed your content. I like how you explain the DES algorithm

💬 2018-09-12 aaa: thanks

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

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

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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. 2018-10-18, 439👍, 4💬

💬 2018-10-18 sam: harry please stop bullying me

DESSubkeysTest.java - DES Key Schedule Algorithm Illustration
This section provides a tutorial Java program, DESSubkeysTest.java, to illustrate how DES key schedule algorithm works. 2018-07-20, 577👍, 2💬

💬 2018-07-20 aqil: havr fun

"OpenSSL" Signing CSR Generated by "keytool"
This chapter provides tutorial notes and example codes on using 'OpenSSL' to act as CA (Certificate Authority). Topics include setting up 'OpenSSL' as CA; using 'keytool' to generate CA private key; using 'keytool' to generate CSR (Certificate Signing Request); using 'OpenSSL' to sign CSR, using 'ke... 2018-07-12, 144👍, 1💬

"openssl pkcs12" Merging Key with Certificate
This section provides a tutorial example on how to merge a private key and its self-signed certificate into a single PKCS#12 file, with can be then encoded as PEM and encrypted with DES. 2018-07-07, 146👍, 1💬

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