Herong's Tutorial Examples: Cryptography

Free Chinese Calendar 2025 - Year of the Snake
Want to know when is the 2025 Chinese New Year day? Look for free Chinese calendars for 2025? Chinese New Year Date for Year 2025 The Snake 2025 January 29 Wednesday Chinese New Year ⇒ Free Chinese Calendar 2026 - Year of the Horse ⇐ Free Chinese Calendar 2024 - Year of the Dragon ⇑ Chinese New Y... 2025-01-12, ≈154🔥, 3💬

💬 2025-01-12 Al Sun: The yearly calendar is very clear and useful. Thank you. Would you have monthly calendars also, in simplified or traditional chi...

💬 2025-01-03 Herong: Hi Don, thanks for the suggestion. I will try to create a monthly calendar. Happy new year to everyone!

💬 2025-01-01 Don Tai: Thank you for sharing your time with the world. Your calendar is very nice. Maybe you could do a version with a single month on ...

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"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. 2022-08-16, ≈71🔥, 8💬

💬 2022-08-16 Ken: Cool tutorial. Thank you!

💬 2019-10-05 Herong: Fatin, what are you getting from the output?

💬 2019-09-27 Fatin: Please help me, i cannot get it that way

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

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

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"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, ≈53🔥, 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 ...

Installing OpenSSL on Windows
This section provides a tutorial example on how to install OpenSSL on a Windows system. 2017-10-29, ≈51🔥, 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 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

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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 MD5 and SHA1 message digest algorithms and implementations, DES, Blowfish and AES secret key cipher algorithms and implementations, ... 2021-08-28, ≈38🔥, 7💬

💬 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...

"keytool" Importing Certificates in DER and PEM
This section provides a tutorial example on how to use 'keytool' to import certificates in DER and PEM formats generated by 'OpenSSL' into 'keystore' files. 2018-06-28, ≈37🔥, 2💬

💬 2016-04-01 MM: Thank you, this is very helpful.

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. 2021-01-08, ≈34🔥, 17💬

💬 2021-01-08 Herong: Abigail, you are welcome!

💬 2021-01-06 Abigail: Thank you so much, just what I needed for my university assignment!

💬 2020-12-05 Herong: Donghua, h is any integer you pick to help generating g.

💬 2020-12-04 Donghua: What's the h means in step three. How to calculate it?

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

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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

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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, ≈26🔥, 11💬

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

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

💬 2018-08-31 Munikumar: Great...

💬 2017-10-24 Siva: Thanks

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

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Validating a Certificate Path with OpenSSL
This section provides a tutorial example on how to perform validation of a certificate path with the 'openssl verify' command. 2015-10-14, ≈24🔥, 5💬

💬 2015-10-14 Herong: Karnan, if the issuer is a root CA, issuer certificate should be in your trusted certificate store. If the issuer is an intermed...

💬 2015-10-13 karnan: how to get issuer certificate

💬 2015-09-02 Liang: Thanks, Yang, This is a very helpful for understanding the basic concept of Crypto/SSL.

💬 2015-08-14 Chris: If you have to specify an intermediate as trusted, that means the intermediate is not qualified to be a signer.

💬 2015-08-12 Aleksandar Kostadinov: I see a strange thing: openssl verify -CApath . <(cd /tmp ; cat server.pem intermediate.pem) That does not work if interm...

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. 2023-02-22, ≈20🔥, 6💬

💬 2023-02-22 aaa: 124, 52, -95, -30, 47, 95, -105, -1, -114, -38, -100, -84, 40, -3, 36, -13

💬 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

"openssl pkcs8" Converting Keys to PKCS#8 Format
This section provides a tutorial example on how to convert a private key file from the traditional format into PKCS#8 format using the 'openssl pkcs8' command. Keys can still be encoded with DER or PEM with or without DES encryption in PKCS#8 format. 2022-03-08, ≈18🔥, 2💬

💬 2022-03-08 randomn: random123

💬 2016-04-12 Nishant Desai: Does anyone knows any library by which i can execute openssl pkcs8 -topk8 -in openssl_key.pem -inform pem -out openssl_key_pk8_e...

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 ...

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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. 2021-10-25, ≈17🔥, 8💬

💬 2021-10-25 kareem: karee

💬 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.

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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. 2022-06-06, ≈15🔥, 12💬

💬 2022-06-06 hello: <script> alert("Hello! I am an alert box!"); </script>

💬 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)

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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'. 2023-05-24, ≈15🔥, 4💬

CipherDES.java - A Java Implementation of DES
This section provides a tutorial Java program, CipherDES.java - A Java Implementation of DES encryption and decryption algorithm. 2017-02-16, ≈15🔥, 9💬

💬 2017-02-16 Herong: Andro, I think implementation of DES using String methods will be slower than using byte and int operations.

💬 2017-02-12 Andro: Good done. I have created my own DES with benefits of string methods in Java. My DES receives binary string and key, then cipher...

💬 2016-03-03 Dede: Helps a lot, currently developping a mobile application that has to do with encryption. Thanks

💬 2015-10-16 Herong: Skip, Good luck on your study!

💬 2015-10-15 Skip: I'm taking a graduate course in cryptography and this was extremely helpful for going from DES visual to DES in java. I really a...

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MD5 Message Digest Algorithm Overview
This section describes the MD5 algorithm - a 5-step process of padding of '1000...', appending message length, dividing as 512-bit blocks, initializing 4 buffers, and 4-round of hashing each block. 2021-10-04, ≈12🔥, 7💬

💬 2016-11-21 this is a burner: concise and accurate, thanks

💬 2016-09-26 brijesh gupta: its helpful

💬 2016-06-17 Ampera: Makasih

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. 2023-06-08, ∼9397🔥, 11💬

💬 2022-12-11 Racheal mweemba: This was helpful

💬 2022-12-11 Racheal Mweemba: ❤️❤️❤️❤️

💬 2022-04-23 Shivam: Please provide the code for the same

💬 2021-12-23 x: 5

💬 2020-11-22 Herong: fab, as shown in the tutorial, the modulus is 35. The encryption key (public key) is 5, and the decryption key (private key) is ...

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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, ∼9192🔥, 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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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. 2023-06-23, ∼8794🔥, 18💬

💬 2023-06-23 rafa: Hello my love

💬 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

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"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. 2021-09-24, ∼8706🔥, 2💬

💬 2021-09-24 samiam: Proc-Type: 4,ENCRYPTED DEK-Info: DES-CBC,65D5EB070215060E 85d+v8K1kPwCgFarsMD+5FpVs6doCZPeCjMr rWzyym5wIKHKqV8tfAjO...Z2JBXMGxAV...

💬 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...

Subkeys of 3DES Encryption
Hi Doc, I have subkeys recovered through DPA. Can 3DES.c be modified to accept these subkeys as inputs for a cryptographic operation? Alternatively, can the main 3DES key be reverse generated from the subkeys? Thanks. jeffrey****alis@gmail.com 2021-10-15, ∼8649🔥, 2💬

💬 2021-10-15 bddsm: This section provides a tutorial example

💬 2015-07-22 Herong: Hi Jeffrey, Which 3DES.c are you referring to? Can you tell me where I can see the code?

Illustration of DSA Algorithm: p,q=7,3
This section provides a tutorial example to illustrate how DSA digital signature algorithm works with small prime modulus p=7 and prime divisor q=3. 2023-05-03, ∼8626🔥, 7💬

💬 2023-05-03 Zavala: Greetings from the Tower

💬 2023-03-27 Davide: Greetings from Italy

💬 2016-03-22 Herong: Peter, I see the issue now. This example needs to be reviewed and updated. Thanks for the feedback.

💬 2016-03-21 peter winzell: x is not selected according to 0 < x < q

💬 2015-10-19 Herong: Hi Marian, do you have a question about this tutorial?

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