Herong's Tutorial Examples: Cryptography

XML Tutorials - Herong's Tutorial Examples
This XML tutorial book is a collection of notes and sample codes written by the author while he was learning XML himself. Topics include introduction to XML, DTD (Document Type Definition), XSD (XML Schema Definition), XPath (XML Path Language), XSL (Extensible Stylesheet Language), XSLT (XSL Transf... 2025-07-18, ≈13🔥, 3💬

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First 8336 Hex Digits of PI
This section provides first 8336 hex digits of constant PI, 3.1415927..., needed for Blowfish encryption algorithm. 2025-04-28, ∼8262🔥, 13💬

💬 2019-04-28 Herong: 8336 Hex Digits. Thanks.

💬 2019-04-26 Harry: Do you mean 8336 digits

💬 2016-10-31 Andres: cool

💬 2016-04-07 Tamas Losonczi: This is great

💬 2016-03-15 Bogdan: Thanks!

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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, ∼8111🔥, 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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"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, ∼6965🔥, 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. 2020-05-19, ∼6751🔥, 4💬

💬 2020-05-19 Nick: test comment

💬 2019-06-17 bIPFaV0PLbO9qrDgn+p43A==: bIPFaV0PLbO9qrDgn+p43A==

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

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

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. 2023-11-19, ∼6504🔥, 10💬

💬 2023-02-23 CYR: Thanks for providing the detail example, it helps me to understand the algorithm a lot. The value for g looks like incorrect to ...

💬 2021-01-09 Flying Horse: Hello Dr Yang, My verification scheme is as follows lhs = (r**s mod p)mod q rhs = ((g**h mod p)*(y**r mod p)) mod q If lhs = rhs...

💬 2021-01-08 Herong: Flying, give us an example to show that this verification scheme is not working?

💬 2021-01-07 Flying Horse: Hello Dr Yang, this is a very helpful tutorial. I am trying a different verification scheme for DSA signature. Unfortunately, it...

💬 2020-06-22 Filip: Very helpful, thanks!

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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/multiplicative notations; EC a... 2024-11-16, ∼6444🔥, 4💬

💬 2022-07-27 Aman: Perfect book to help my 'encoding' project. Thank you!

💬 2020-06-23 Herong: Chris, contact me by email. I will send you a PDF copy. Thanks for your comment.

💬 2020-06-22 chris: Sorry for fuss. Bought this ebook on google. bad idea. Should have not done that and just got the physical book or maybe ebook o...

💬 2019-01-01 Yale: Thank you!

AES MixColumns() Procedure Algorithm
A detailed description of the MixColumns() procedure algorithm is provided. The MixColumns() procedure performs a matrix multiplication of a given 'state' with a static matrix. The MixColumns() procedure is used in the AES encryption process. 2023-06-10, ∼6423🔥, 3💬

💬 2021-12-24 Muhammad Ghulam Ghouse: Appreciated

💬 2021-11-15 123: AD E0 B8 1E BF B4 41 27 5D 52 11 98 30 AE F1 E5

DsaSignatureGenerator.java - Generating DSA Digital Signature
This section provides tutorial example on how to generate a digital signature for a message file with a DSA private key using the SHA1withDSA algorithm. 2017-03-13, ∼6192🔥, 5💬

💬 2017-03-13 dingdong: heheheheehhe

💬 2016-10-15 Herong: Akash, can you check to ensure your key is a DSA key?

💬 2016-10-14 Akash: Exception occurs as follows: java.security.spec.InvalidKeySpecExc eption:Inappropriate key specification what it means? can you ...

Using Certificates in Firefox
This chapter provides tutorial notes and example codes on using certificates in Firefox. Topics include why Web browsers need certificates; viewing the certificate from an https Web server; exporting a certificate from Firefox to a certificate file; importing a CA certificate into Firefox. 2017-08-31, ∼6172🔥, 1💬

💬 2017-08-31 bobby: ok will do

What is ECB (Electronic CodeBook) Operation Mode?
This section describes what is ECB (Electronic CodeBook) Operation Mode - each plaintext block is encrypted independently without any input from other blocks. 2024-01-29, ∼5865🔥, 5💬

💬 2020-10-18 Herong: donjo, there is no real applications that use the ECB mode.

💬 2020-10-16 donjo dumdum: What is application of ECB mode operation

💬 2016-01-10 Todd: Thanks!

DES (Data Encryption Standard) Cipher Algorithm
This section describes DES (Data Encryption Standard) algorithm - A 16-round Feistel cipher with block size of 64 bits. 2015-11-05, ∼5830🔥, 8💬

💬 2015-11-05 Herong: The Anh, good question. If your key is less than 64 bits, you can pad it with 0 or 1. Or use a hash algorithm to produce 64 bits...

💬 2015-11-04 The Anh: what if my key don't have enough bit?

💬 2015-11-04 Herong: Zaeem, take a look at the source code at Simple Cryptographer - Simple DES/AES Implementation in C#

💬 2015-11-03 zaeem: how to implement on windows form in c#

💬 2015-10-03 Herong: Mihir, what type of algorithm are you looking for?

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"OpenSSL" Managing Serial Numbers when Signing CSR
This section provides a tutorial example on how to manage serial number when using 'OpenSSL' to sign a CSR (Certificate Signing Request) generated by 'keytool' with CA's private key. 2022-05-25, ∼5418🔥, 1💬

"secp256r1" - For 256-Bit ECC Keys
This section describes 'secp256r1' elliptic curve domain parameters for generating 256-Bit ECC Keys as specified by secg.org. 2023-10-20, ∼5400🔥, 1💬

💬 2023-10-20 Duy: hello

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. 2020-06-04, ∼5389🔥, 12💬

💬 2020-06-04 ben: How are you?

💬 2018-04-07 Digital Signature Algorithm: Conclusions: DSA (Digital Signature Algorithm) uses public key and private key to generate and verify digital signatures. DSA pu...

💬 2018-04-07 Submit Your Comment: Please write meaningful comments. Thanks! ☺

💬 2018-04-07 world: hello

💬 2018-02-20 amit: hello

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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. 2022-08-23, ∼5352🔥, 4💬

💬 2022-08-23 lol: meanning ful comments

💬 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 .

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, ∼5297🔥, 1💬

💬 2019-02-18 Ggf: hello

Viewing Components of RSA Keys
This section provides a tutorial example on how to view different components of a pair of RSA private key and public key using the OpenSSL command line tool. 2016-03-14, ∼4635🔥, 2💬

💬 2015-10-02 Herong: Looks like someone is testing Base64 encoding here :-)

💬 2015-10-01 1: CSENry/M1h2AhxGSxQluy4b1ynzBGWeO320C AwEAAQJAbQQn... IQCoo0AdFXm789FfHuB+mVIKNtBLTAQNaMuX z6lXl7Ib7Q==

RsaKeyGenerator.java for RSA Key Generation
This section describes the initial draft of a RSA public key and private key generation implementation using the java.math.BigInteger class. 2017-01-05, ∼4384🔥, 2💬

💬 2017-01-05 Herong: Alex, you are right. q should be selected independently from p. I will make a change in the next revision.

💬 2016-12-28 Alex T.: Using nextProbablePrime() to compute q appears somewhat risky to me: An attacker with the knowledge of N=p*q could simply comput...

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. 2020-02-23, ∼4376🔥, 4💬

💬 2020-02-23 Herong: Sanjay, you are welcome!

💬 2020-02-17 Sanjay: Thank u so much

💬 2019-01-29 nilo: Hola

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

EC Key in PEM File Format
This section provides a tutorial example on the EC key PEM file format. EC domain parameters are stored together with the private key. 2023-09-17, ∼4278🔥, 1💬

💬 2023-09-17 ecformat: this is to test EC format

Illustration of RSA Algorithm: p,q=7,19
This section provides a tutorial example to illustrate how RSA public key encryption algorithm works with 2 small prime numbers 7 and 19. 2016-02-29, ∼4230🔥, 3💬

💬 2015-11-01 Herong: Jun, AES algorithm is added now, see Introduction to AES (Advanced Encryption Standard) .

💬 2015-10-17 Herong: Jun, thank you for pointing out the mistake. I will correct it in the next version. AES will also be included.

💬 2015-10-16 jun: thanks a lot. your book makes everything clear for me except that I have not found a char for AES. By the way, I think "Generati...

RSA Implementation using java.math.BigInteger Class
This chapter provides tutorial notes and example codes on RSA implementation using Java BigInteger class. Topics include introduction of the java.math.BigInteger class; generating large probable prime numbers; generating RSA public key and private key; validating RSA keys; determining cleartext and ... 2016-02-29, ∼4130🔥, 3💬

💬 2016-02-29 Herong: sah, is that an encoded comment?

💬 2016-02-28 sah: 7C4A8D09CA3762AF61E59520943DC26494F8 941B

💬 2014-02-06 Chinmayee: Searching for a book on RSAKey generation and got your link. Have not gone through the pdf yet. If find it good, will go for the...

Generate secp256k1 Keys with OpenSSL
This section provides a tutorial example on how to generate EC (Elliptic Curve) private and public key pairs using secp256k1 domain parameters. 2023-08-10, ∼4091🔥, 3💬

💬 2023-08-10 emanuel: thanks , it was realz helpfull. can zou tell me how can i encrzpt with btc key some message, because btc use the same secp256k1 ...

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. 2022-12-26, ∼3906🔥, 7💬

💬 2022-12-07 sudarshan: hello

💬 2018-12-22 Hari: Hello

💬 2016-01-02 sivaprakash: nice

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