HC-256 is a stream cipher designed to provide bulk encryption in software at high speeds while permitting strong confidence in its security.[1] A 128-bit variant was submitted as an eSTREAM cipher candidate and has been selected as one of the four final contestants in the software profile.[2][3]
The algorithm is designed by Hongjun Wu, and was first published in 2004. It is not patented.
Internally, it consists of two secret tables (P and Q). Each table contains 1024 32-bit words. For each state update one 32-bit word in each table is updated using a non-linear update function. After 2048 steps all elements of the tables have been updated.
It generates one 32-bit word for each update step using a 32-bit to 32-bit mapping function similar to the output function of the Blowfish cipher. Finally a linear bit-masking function is applied to generate an output word. It uses the two message schedule functions in the hash functionSHA-256 internally, but with the tables P and Q as S-boxes.
HC-128 is similar in function, and reduces each of key length, nonce, number of words in the tables P and Q, and number of table updating steps by half.[2]
Performanceedit
The performance of HC-256 is estimated by its author to be about 4 cycles per byte on a Pentium 4 processor. However the initialization phase of the cipher includes expanding the 256-bit key into the tables P, Q and then running the cipher for 4096 steps. The author of HC-256 estimates this process to take around 74,000 cycles.
For HC-128 an encryption speed of about 3 cycles per byte on a Pentium M processor are cited.
The implementation of HC-128 on various computing structures is studied in detail, with significant performance gains compared to naive SW implementation.[4][5]
Referencesedit
^ abWu, Hongjun (2004). "A New Stream Cipher HC-256" (PDF). Fast Software Encryption – FSE 2004, LNCS 3017: 226–244.
^Chattopadhyay, Anupam; Khalid, Ayesha; Maitra, Subhamoy; Raizada, Shashwat (2012). "Designing high-throughput hardware accelerator for stream cipher HC-128". 2012 IEEE International Symposium on Circuits and Systems. pp. 1448–1451. doi:10.1109/ISCAS.2012.6271518. ISBN978-1-4673-0219-7. S2CID 5520516.
^Khalid, Ayesha; Bagchi, Deblin; Paul, Goutam; Chattopadhyay, Anupam (2013). "Optimized GPU Implementation and Performance Analysis of HC Series of Stream Ciphers". Information Security and Cryptology – ICISC 2012. Lecture Notes in Computer Science. Vol. 7839. pp. 293–308. doi:10.1007/978-3-642-37682-5_21. ISBN978-3-642-37681-8.
External linksedit
eSTREAM page on HC-256
This cryptography-related article is a stub. You can help Wikipedia by expanding it.
stream, cipher, designed, provide, bulk, encryption, software, high, speeds, while, permitting, strong, confidence, security, variant, submitted, estream, cipher, candidate, been, selected, four, final, contestants, software, profile, algorithm, designed, hong. HC 256 is a stream cipher designed to provide bulk encryption in software at high speeds while permitting strong confidence in its security 1 A 128 bit variant was submitted as an eSTREAM cipher candidate and has been selected as one of the four final contestants in the software profile 2 3 The algorithm is designed by Hongjun Wu and was first published in 2004 It is not patented Contents 1 Function 2 Performance 3 References 4 External linksFunction editHC 256 has a 256 bit key and an initialization vector nonce of 256 bits 1 Internally it consists of two secret tables P and Q Each table contains 1024 32 bit words For each state update one 32 bit word in each table is updated using a non linear update function After 2048 steps all elements of the tables have been updated It generates one 32 bit word for each update step using a 32 bit to 32 bit mapping function similar to the output function of the Blowfish cipher Finally a linear bit masking function is applied to generate an output word It uses the two message schedule functions in the hash function SHA 256 internally but with the tables P and Q as S boxes HC 128 is similar in function and reduces each of key length nonce number of words in the tables P and Q and number of table updating steps by half 2 Performance editThe performance of HC 256 is estimated by its author to be about 4 cycles per byte on a Pentium 4 processor However the initialization phase of the cipher includes expanding the 256 bit key into the tables P Q and then running the cipher for 4096 steps The author of HC 256 estimates this process to take around 74 000 cycles For HC 128 an encryption speed of about 3 cycles per byte on a Pentium M processor are cited The implementation of HC 128 on various computing structures is studied in detail with significant performance gains compared to naive SW implementation 4 5 References edit a b Wu Hongjun 2004 A New Stream Cipher HC 256 PDF Fast Software Encryption FSE 2004 LNCS 3017 226 244 a b Wu Hongjun 2004 The Stream Cipher HC 128 PDF a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help The eSTREAM Project Chattopadhyay Anupam Khalid Ayesha Maitra Subhamoy Raizada Shashwat 2012 Designing high throughput hardware accelerator for stream cipher HC 128 2012 IEEE International Symposium on Circuits and Systems pp 1448 1451 doi 10 1109 ISCAS 2012 6271518 ISBN 978 1 4673 0219 7 S2CID 5520516 Khalid Ayesha Bagchi Deblin Paul Goutam Chattopadhyay Anupam 2013 Optimized GPU Implementation and Performance Analysis of HC Series of Stream Ciphers Information Security and Cryptology ICISC 2012 Lecture Notes in Computer Science Vol 7839 pp 293 308 doi 10 1007 978 3 642 37682 5 21 ISBN 978 3 642 37681 8 External links editeSTREAM page on HC 256 nbsp This cryptography related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title HC 256 amp oldid 1103881306, wikipedia, wiki, book, books, library,
