Cryptanalysis of the hash functions MD4 and RIPEMD
22 May 2005-pp 1-18
TL;DR: In this article, a chosen-message pre-image attack on MD4 with complexity below 28 was presented, where the complexity is only a single MD4 computation and a random message is a weak message with probability 2−2 to 2−6.
Abstract: MD4 is a hash function developed by Rivest in 1990 It serves as the basis for most of the dedicated hash functions such as MD5, SHAx, RIPEMD, and HAVAL In 1996, Dobbertin showed how to find collisions of MD4 with complexity equivalent to 220 MD4 hash computations In this paper, we present a new attack on MD4 which can find a collision with probability 2−2 to 2−6, and the complexity of finding a collision doesn't exceed 28 MD4 hash operations Built upon the collision search attack, we present a chosen-message pre-image attack on MD4 with complexity below 28 Furthermore, we show that for a weak message, we can find another message that produces the same hash value The complexity is only a single MD4 computation, and a random message is a weak message with probability 2−122
The attack on MD4 can be directly applied to RIPEMD which has two parallel copies of MD4, and the complexity of finding a collision is about 218 RIPEMD hash operations
Citations
More filters
14 Aug 2005
TL;DR: This is the first attack on the full 80-step SHA-1 with complexity less than the 280 theoretical bound, and it is shown that collisions ofSHA-1 can be found with complexityLess than 269 hash operations.
Abstract: In this paper, we present new collision search attacks on the hash function SHA-1. We show that collisions of SHA-1 can be found with complexity less than 269 hash operations. This is the first attack on the full 80-step SHA-1 with complexity less than the 280 theoretical bound.
1,600 citations
14 Aug 2005
TL;DR: Using the new techniques, this paper can find collisions of the full 80-step SHA-0 with complexity less than 239 hash operations.
Abstract: In this paper, we present new techniques for collision search in the hash function SHA-0. Using the new techniques, we can find collisions of the full 80-step SHA-0 with complexity less than 239 hash operations.
450 citations
01 Jan 2009
TL;DR: Together with the Threefish large-block cipher at Skein's core, this design provides a full set of symmetric cryptographic primitives suitable for most modern applications.
Abstract: Executive Summary Skein is a new family of cryptographic hash functions. Its design combines speed, security, simplicity , and a great deal of flexibility in a modular package that is easy to analyze. Skein is fast. Skein-512—our primary proposal—hashes data at 6.1 clock cycles per byte on a 64-bit CPU. This means that on a 3.1 GHz x64 Core 2 Duo CPU, Skein hashes data at 500 MBytes/second per core—almost twice as fast as SHA-512 and three times faster than SHA-256. An optional hash-tree mode speeds up parallelizable implementations even more. Skein is fast for short messages, too; Skein-512 hashes short messages in about 1000 clock cycles. Skein is secure. Its conservative design is based on the Threefish block cipher. The current best attack on the tweaked Threefish-512 is on 35 of 72 rounds, for a safety factor of just over 2.0. For comparison, at a similar stage in the standardization process, the AES encryption algorithm had an attack on 6 of 10 rounds, for a safety factor of only 1.7. Additionally, Skein has a number of provably secure properties, greatly increasing confidence in the algorithm. Skein is simple. Using only three primitive operations, the Skein compression function can be easily understood and remembered. The rest of the algorithm is a straightforward iteration of this function. Skein is flexible. Skein is defined for three different internal state sizes—256 bits, 512 bits, and 1024 bits—and any output size. This allows Skein to be a drop-in replacement for the entire SHA family of hash functions. A completely optional and extendable argument system makes Skein an efficient tool to use for a very large number of functions: PRNG, stream cipher, key derivation function, authentication without the overhead of HMAC, and personalization capability. All these features can be implemented with very low overhead. Together with the Threefish large-block cipher at Skein's core, this design provides a full set of symmetric cryptographic primitives suitable for most modern applications. Skein is efficient on a variety of platforms, both hardware and software. Skein-512 can be implemented in about 200 bytes of state. Small devices, such as 8-bit smart cards, can implement Skein-256 using about 100 bytes of memory. Larger devices can implement the larger versions of Skein to achieve faster speeds. Skein was designed by a team of highly experienced cryptographic experts from academia and industry , with expertise in cryptography, security analysis, software, chip design, and …
377 citations
Journal Article•
TL;DR: In this paper, it was shown that while the function proposed by Micciancio is not collision resistant, it can be easily modified to achieve collision resistance under essentially the same complexity assumptions on cyclic lattices.
Abstract: In (Micciancio, FOCS 2002), it was proved that solving the generalized compact knapsack problem on the average is as hard as solving certain worst-case problems for cyclic lattices. This result immediately yielded very efficient one-way functions whose security was based on worst-case hardness assumptions. In this work, we show that, while the function proposed by Micciancio is not collision resistant, it can be easily modified to achieve collision resistance under essentially the same complexity assumptions on cyclic lattices. Our modified function is obtained as a special case of a more general result, which yields efficient collision-resistant hash functions based on the worst-case hardness of various new problems. These include new problems from algebraic number theory as well as classic lattice problems (e.g., the shortest vector problem) over ideal lattices, a class of lattices that includes cyclic lattices as a special case.
327 citations
03 Dec 2006
TL;DR: A method to search for characteristics in an automatic way for multi-block attacks, and as a proof of concept, gives a two-block collision for 64-step SHA-1 based on a new characteristic.
Abstract: The most efficient collision attacks on members of the SHA family presented so far all use complex characteristics which were manually constructed by Wang et al. In this report, we describe a method to search for characteristics in an automatic way. This is particularly useful for multi-block attacks, and as a proof of concept, we give a two-block collision for 64-step SHA-1 based on a new characteristic. The highest number of steps for which a SHA-1 collision was published so far was 58. We also give a unified view on the expected work factor of a collision search and the needed degrees of freedom for the search, which facilitates optimization.
286 citations
References
More filters
Book•
01 Jan 1993TL;DR: This book introduces a new cryptographic method, called differential cryptanalysis, which can be applied to analyze cryptosystems, and describes the cryptanalysis of DES, deals with the influence of its building blocks on security, and analyzes modified variants.
Abstract: DES, the Data Encryption Standard, is one of several cryptographic standards. The authors of this text detail their cryptanalytic "attack" upon DES and several other systems, using creative and novel tactics to demonstrate how they broke DES up into 16 rounds of coding. The methodology used offers valuable insights to cryptographers and cryptanalysts alike in creating new encryption standards, strengthening current ones, and exploring new ways to test important data protection schemes. This book introduces a new cryptographic method, called differential cryptanalysis, which can be applied to analyze cryptosystems. It describes the cryptanalysis of DES, deals with the influence of its building blocks on security, and analyzes modified variants. The differential cryptanalysis of "Feal" and several other cryptosystems is also described. This method can also be used to cryptanalyze hash functions, as is exemplified by the cryptanalysis of "Snefru".
1,009 citations
11 Aug 1990
TL;DR: The MD4 message digest algorithm takes an input message of arbitrary length and produces an output 128-bit "fingerprint" or "message digest", in such a way that it is (hopefully) computationally infeasible to produce two messages having the same message digest, or to produce any message having a given prespecified target message digest.
Abstract: The MD4 message digest algorithm takes an input message of arbitrary length and produces an output 128-bit "fingerprint" or "message digest", in such a way that it is (hopefully) computationally infeasible to produce two messages having the same message digest, or to produce any message having a given prespecified target message digest. The MD4 algorithm is thus ideal for digital signature applications: a large file can be securely "compressed" with MD4 before being signed with (say) the RSA public-key cryptosystem.The MD4 algorithm is designed to be quite fast on 32-bit machines. For example, on a SUN Sparc station, MD4 runs at 1,450,000 bytes/second (11.6 Mbit/sec). In addition, the MD4 algorithm does not require any large substitution tables; the algorithm can be coded quite compactly.The MD4 algorithm is being placed in the public domain for review and possible adoption as a standard.
550 citations
21 Feb 1996
TL;DR: A new version of RIPEMD with a 160-bit result is proposed, as well as a plug-in substitute for RIPEMd with a 128- bit result, and the software performance of several MD4-based algorithms is compared.
Abstract: Cryptographic hash functions are an important tool in cryptography for applications such as digital fingerprinting of messages, message authentication, and key derivation. During the last five years, several fast software hash functions have been proposed; most of them are based on the design principles of Ron Rivest's MD4. One such proposal was RIPEMD, which was developed in the framework of the EU project RIPE (Race Integrity Primitives Evaluation). Because of recent progress in the cryptanalysis of these hash functions, we propose a new version of RIPEMD with a 160-bit result, as well as a plug-in substitute for RIPEMD with a 128-bit result. We also compare the software performance of several MD4-based algorithms, which is of independent interest.
519 citations
Proceedings Article•
01 Jan 2004
TL;DR: In this article, a pseudo-collision for MD5 which is made of the same message with two different sets of initial values was found. But this was not the case for MD4, which is the hash function designed by Ron Rivest [9] as a strengthened version of MD4.
Abstract: MD5 is the hash function designed by Ron Rivest [9] as a strengthened version of MD4[8]. In 1993 Bert den Boer and Antoon Bosselaers [1] found pseudo-collision for MD5 which is made of the same message with two different sets of initial value. H. Dobbertin[3] found another kind of collision which consists of two different 512-bit messages with a chosen initial value I
470 citations
Posted Content•
TL;DR: In 1993 Bert den Boer and Antoon Bosselaers found pseudo-collision for MD5 which is made of the same message with two different sets of initial value.
Abstract: MD5 is the hash function designed by Ron Rivest [9] as a strengthened version of MD4[8]. In 1993 Bert den Boer and Antoon Bosselaers [1] found pseudo-collision for MD5 which is made of the same message with two different sets of initial value. H. Dobbertin[3] found another kind of collision which consists of two different 512-bit messages with a chosen initial value I
406 citations