Herong's Tutorial Examples: Cryptography

Free Chinese Calendar 2026 - Year of the Horse
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"OpenSSL" Generating Certificates in DER and PEM
This section provides a tutorial example on how to generate certificates in DER and PEM formats using 'OpenSSL'. 2026-01-11, ≈15🔥, 5💬

Is EC Private Key Secure
This section discusses the question of: how secure is the EC (Elliptic Curve) key pair? Or how hard is it someone to figure out the private key from a given EC public key? 2025-09-06, ∼411🔥, 1💬

Importing CA Certificate into Firefox
This section provides a tutorial example on how to import a CA certificate into Firefox in the 'Authorities' category. 2025-06-18, ∼633🔥, 1💬

AES Equivalent Decryption Algorithm
The equivalent decryption algorithm of the AES-128 encryption is provided. It follows the same sequence of applying transformation procedures as the encryption algorithm, but uses modified round keys. 2025-06-08, ∼807🔥, 2💬

EC (Elliptic Curve) Key Pair
This chapter provides tutorial notes on EC (Elliptic Curve) key pair. Topics include definition of EC private and public key pair; example of elliptic curve and subgroup used to generate good EC key pair; using OpenSSL command line tool to generate EC key pairs. 2025-05-22, ∼1382🔥, 2💬

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, ∼8331🔥, 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!

(More comments ...)

OpenSSL Generating and Managing RSA Keys
This chapter provides tutorial notes and example codes on managing RSA keys with OpenSSL. Topics include generating new RSA keys; viewing existing RSA keys; encrypting RSA keys with DES algorithm to protect them with passwords. 2025-02-21, ∼302🔥, 1💬

💬 2025-02-21 bz: good for helping me

Secret Key Generation and Management
This chapter provides tutorial notes and example codes on secret keys. Topics include secret keys for Blowfish, DES, or HmacMD5 encryption algorithms; key generator class; test program to generate secret keys and save them in files. 2025-01-29, ∼282🔥, 1💬

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, ∼6564🔥, 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!

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. 2024-04-23, ≈28🔥, 12💬

💬 2024-04-23 ☺: meaningful comments. Thanks! ☺

💬 2023-02-13 Amar: Amar

💬 2022-12-02 Victor: meaningful comments.

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

💬 2017-03-15 noname: thanks

(More comments ...)

Full Version in PDF/EPUB
Information on how to obtain the full version of this book in PDF, EPUB, or other format. 2024-03-13, ∼9322🔥, 37💬

💬 2024-03-13 aridj: thanks

💬 2021-07-27 attila: thanks

💬 2019-07-04 aladdin: thanks

💬 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

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What Is PKCS5Padding?
This section describes what is PKCS5Padding - a schema to pad cleartext to be multiples of 8-byte blocks. 2024-01-31, ≈50🔥, 38💬

💬 2023-11-02 ayyappa: enjoy

💬 2023-04-12 {"partnerReferenceNo": "APP12345: ok

💬 2023-01-18 Servant of Elon Musk's Regent: You are the chosen one!

💬 2022-11-17 Elon Musk's Regent: mommy

💬 2022-11-14 Elon Musk: Giving away twitter to the first person to reply and call me mommy

(More comments ...)

Blowfish Decryption Algorithm
This section describes the Blowfish decryption algorithm, which is identical to the encryption algorithm step by step in the same order, only with the sub-keys applied in the reverse order. 2024-01-29, ∼1581🔥, 3💬

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, ∼5880🔥, 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!

Certificate in PEM Format
This section describes what is certificate PEM (Privacy Enhanced Mail) format - A format uses PEM idea to convert a certificate in DER format to a message of printable characters. The conversion uses the Base64 encoding. 2023-12-22, ≈17🔥, 8💬

💬 2023-11-13 shady: MIICUTCCAfugAwIBAgIBADANBgkqhkiG9w0B AQQFADBXMQswCQYDVQQGEwJDTjELMAkGA1UECBMCUE4xCzAJBgNVBAcTAkNOMQsw CQYDVQQKEwJPTjELMAkGA1UECxM...

💬 2023-10-16 subbarao: thanks

💬 2021-12-27 Azul: Why do you want me to write things like that?

💬 2020-02-23 Herong: Mark, if your certificate is signed by your own CA, put it on the Apache server together with the CA certificate to test. Other ...

💬 2020-02-17 mark scorfield: Hi i have a pem certificate x509 that i would like to share against my own certificate signing authority , what is the best way ...

(More comments ...)

Viewing Components of Certificate Signing Request
This section provides a tutorial example on how to view different components of a CSR (Certificate Signing Request) for your public key with OpenSSL. 2023-12-17, ∼893🔥, 5💬

💬 2023-12-17 Herong: NB, Thanks for your comments. I see the value of signing the CSR now and will update the book accordingly.

💬 2023-12-15 NB: Your CSR does not contain your private key. It contains your public key and information about the domain(s) for which it should ...

💬 2014-03-29 Herong: Hi Mike, Sorry for the inconvenience. HTML tags are supported, but they are limited to admin users only to reduce spamming and h...

💬 2014-03-23 Mike: Wow. What a waste of time trying to make a legible comment post. No instructions on how to get a paragraph break, include a angl...

💬 2014-03-23 Mike: You made a note in "Viewing Components of Certificate Signing Request" where you said, "The request is signed with my private ke...

Encrypting RSA Keys
This section provides a tutorial example on how to store RSA keys encrypted with password protection. 2023-12-12, ∼590🔥, 1💬

Full Version in PDF/EPUB
Information on how to obtain the full version of this book in PDF, EPUB, or other format. 2023-12-06, ∼677🔥, 2💬

💬 2023-12-06 Herong: Devang, can you send me your order information to me at herong_yang@yahoo.com? Thanks.

💬 2023-12-05 Devang: I purchased the book from amazon a d sent the mail with order details but did not receive book in pdf format. Could you please c...

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, ∼6539🔥, 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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What Is PKCS#8?
This section describes what is PKCS#8 - One of the PKCS (Public Key Cryptography Standards) used to store a single private key. A PKCS#8 file can be encrypted with a password to protect the private key. 2023-11-15, ∼668🔥, 4💬

What Is ECDH Key Exchange
This section introduces what is ECDH Key Exchange - a protocol that uses the Elliptic Curve group property to establish a shared secret key without sending it directly to each other. 2023-11-09, ∼3389🔥, 3💬

💬 2021-11-08 Carol: Thanks

Blowfish - 8-Byte Block Cipher
This chapter provides tutorial examples and notes about Blowfish block cipher. Topics include Blowfish encryption and decryption algorithm; Blowfish sub-key generation schema, Blowfish algorithm implementation in Java. 2023-10-24, ∼1058🔥, 4💬

💬 2023-10-24 test: 018a35f5-eed3-7a43-99d2-a6a22956bab7

💬 2022-06-21 sad: hello world

💬 2019-12-16 gio: i love you

"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, ∼5511🔥, 1💬

💬 2023-10-20 Duy: hello

RSA Public Key Encryption Algorithm
This section describes the RSA public key encryption algorithm. Generating public and private keys used in RSA encryption requires two large prime numbers. 2023-10-16, ∼403🔥, 2💬

💬 2023-10-16 subbarao: thanks for giving wonderful knowledge

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