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; ... 2019-07-06, 918👍, 3💬

💬 2019-07-02 Eleftheria Drosopoulou: Hello Herong, Nice blog! I am editor at Java Code Geeks (www.javacodegeeks.com). We have the JCG program (see www.javacodegeeks....

💬 2019-01-01 Yale: Thank you!

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Installing OpenSSL on Windows
This section provides a tutorial example on how to install OpenSSL on a Windows system. 2017-10-29, 44923👍, 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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"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. 2019-10-05, 37947👍, 7💬

💬 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 Herong: Poshak, do you need any help with your certificate?

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

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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, 28132👍, 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 ...

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. 2019-10-22, 27895👍, 17💬

💬 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 "**"?

💬 2017-03-10 appalaraju: useful

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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 AES, blowfish, certificate, cipher, decryption, DES, digest, encryption, keytool, MD5, OpenSSL, PEM, PKCS#8, PKCS#12, private key, p... 2017-08-05, 26978👍, 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...

What Is PKCS5Padding?
This section describes what is PKCS5Padding - a schema to pad cleartext to be multiples of 8-byte blocks. 2016-06-16, 23014👍, 8💬

💬 2016-06-16 yo: hola pescado

💬 2016-04-04 ankit: this is me.

💬 2016-01-28 John: Herong, thanks a lot.

💬 2016-01-27 Herong: John, the schema of PKCS7Padding can be described as below: Pad the input at the trailing end with k−(l mod k) octets with the s...

💬 2016-01-24 John: For PKCS7Padding, what is the schema? I'm interested to what is after 0x0909090909090909099

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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, 18343👍, 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...

"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, 17607👍, 2💬

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

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, 16754👍, 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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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, 12064👍, 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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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, 11127👍, 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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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, 10339👍, 4💬

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

💬 2017-03-15 noname: thanks

💬 2016-01-25 Dev: hello

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, 9882👍, 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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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. 2016-11-21, 8837👍, 6💬

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

💬 2016-09-26 brijesh gupta: its helpful

💬 2016-06-17 Ampera: Makasih

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, 8565👍, 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

"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. 2016-04-12, 7450👍, 1💬

💬 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...

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, 6845👍, 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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PDF Printing Version: Cryptography Tutorials
Information on how to obtain the PDF version of this book for printing. 2019-07-04, 6782👍, 35💬

💬 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

💬 2018-09-12 aaa: thanks

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

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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. 2019-04-29, 5360👍, 10💬

💬 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, 5141👍, 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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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, 4716👍, 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 ...

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. 2016-03-30, 4334👍, 2💬

💬 2016-03-30 Herong: Bcbin, why don't you post your question here? Maybe others can help you too. Or send me an email directly.

💬 2016-03-27 bcbin: my name is bcbin, my email is bcbin@yahoo.com. please connecting me. i need you help ):

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 2015-07-23, 3645👍, 1💬

💬 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. 2018-04-24, 3489👍, 5💬

💬 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?

💬 2015-10-18 Marian: when q=3 x = 5 # selected: 0 < x < q

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