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Installing OpenSSL on Windows
This section provides a tutorial example on how to install OpenSSL on a Windows system.
2017-06-11, 38674👍, 17💬

💬 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!

💬 2016-11-11 Herong: Blessing, do you know in which folder you installed OpenSSL? You may want to try to run the openssl command with the path name i...

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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.
2017-05-27, 26804👍, 5💬

💬 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...

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

💬 2015-09-23 Rohan: Very helpful. Thanks :)

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.
2017-04-01, 20331👍, 13💬

💬 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

💬 2016-12-04 Herong: Krishna, you are welcome!

💬 2016-12-02 Krishna: Very useful SIR, thank you

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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, 15336👍, 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...

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, 15058👍, 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 intermedia...

What Is PKCS5Padding?
This section describes what is PKCS5Padding - a schema to pad cleartext to be multiples of 8-byte blocks.
2016-06-16, 13166👍, 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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"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.
2016-06-27, 13109👍, 2💬

💬 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 ...

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.
2017-08-24, 11481👍, 6💬

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

💬 2016-10-24 appu: thanks!

💬 2016-09-01 Shubham: well done.

💬 2016-02-18 saravanan: thanks

💬 2016-02-09 rajkumar: the given algorithm will be very useful........

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"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.
2016-04-01, 9040👍, 1💬

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

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.
2017-05-18, 8947👍, 4💬

💬 2017-03-07 g: gud

💬 2016-01-19 stephie: hai how are you

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, 8749👍, 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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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.
2017-06-15, 6772👍, 9💬

💬 2017-06-15 Azaz: Not that much useful

💬 2015-12-15 Aleksandar: I want to encrypt using DES

💬 2015-10-31 star: Those left shifts were helpful, Thanks ☺

💬 2015-10-24 Herong: Yes. The world is wonderful and beautiful! :-)

💬 2015-10-19 jaffa: beautiful

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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, 5551👍, 6💬

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

💬 2016-09-26 brijesh gupta: its helpful

💬 2016-06-17 Ampera: Makasih

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.
2017-04-23, 5245👍, 12💬

💬 2017-04-23 aa: thanks

💬 2017-02-15 gg: lolol

💬 2016-11-21 allas: super

💬 2016-11-21 priya: good

💬 2016-08-17 revathiganeshan: it is very usefull to me

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PDF Printing Version: Cryptography Tutorials
Information on how to obtain the PDF version of this book for printing.
2017-08-18, 5107👍, 30💬

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

💬 2017-08-15 James Deam: Thanks! Amazing..

💬 2017-06-26 sunil: Good material

💬 2017-02-17 xiaoxiaoyuanzi: the one i'm looking for, Thanks!

💬 2017-02-14 kiki: thanks, great book

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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.
2017-03-30, 5021👍, 3💬

💬 2017-03-15 noname: thanks

💬 2016-01-25 Dev: hello

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.
2015-11-03, 4472👍, 1💬

💬 2015-11-03 cpp: hello

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'.
2016-01-18, 3840👍, 4💬

💬 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

💬 2015-09-30 Hassan: hassan.ali.shaheen@gmail.com

First 8336 Hex Digits of PI
This section provides first 8336 hex digits of constant PI, 3.1415927..., needed for Blowfish encryption algorithm.
2016-10-31, 3748👍, 8💬

💬 2016-10-31 Andres: cool

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

💬 2016-03-15 Bogdan: Thanks!

💬 2015-12-03 Herong: Sadi, we only need (18*32+4*256*32)/4=8336 hex digits for the Blowfish encryption algorithm. I have typos in my tutorials. I wil...

💬 2015-12-02 Sadi: Sorry, I meant "8336 and not 8366"... Also would you like to compare these with "http://hexpi.sourceforge.net/" as there are som...

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"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, 3534👍, 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...

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, 2426👍, 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 ):

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, 2045👍, 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...

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, 2036👍, 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 ...

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.
2016-01-10, 2013👍, 2💬

💬 2016-01-10 Todd: Thanks!

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