what is discrete logarithm problem

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New features of this computation include a modified method for obtaining the logarithms of degree two elements and a systematically optimized descent strategy. This is the group of has this important property that when raised to different exponents, the solution distributes [2] In other words, the function. Therefore, it is an exponential-time algorithm, practical only for small groups G. More sophisticated algorithms exist, usually inspired by similar algorithms for integer factorization. This is super straight forward to do if we work in the algebraic field of real. [26][27] The same technique had been used a few weeks earlier to compute a discrete logarithm in a field of 3355377147 elements (an 1175-bit finite field).[27][28]. Similarly, the solution can be defined as k 4 (mod)16. where \(u = x/s\), a result due to de Bruijn. Several important algorithms in public-key cryptography, such as ElGamal base their security on the assumption that the discrete logarithm problem over carefully chosen groups has no efficient solution. It is based on the complexity of this problem. 'I N P C. NP-complete. stream Suppose our input is \(y=g^\alpha \bmod p\). robustness is free unlike other distributed computation problems, e.g. For instance, consider (Z17)x . Weisstein, Eric W. "Discrete Logarithm." (Also, these are the best known methods for solving discrete log on a general cyclic groups.). Therefore, the equation has infinitely some solutions of the form 4 + 16n. << We shall see that discrete logarithm The discrete logarithm is just the inverse operation. . 24 0 obj Based on this hardness assumption, an interactive protocol is as follows. Use linear algebra to solve for \(\log_g y = \alpha\) and each \(\log_g l_i\). When \(|x| \lt \sqrt{N}\) we have \(f_a(x) \approx \sqrt{a N}\). for every \(y\), we increment \(v[y]\) if \(y = \beta_1\) or \(y = \beta_2\) modulo These new PQ algorithms are still being studied. Joppe W. Bos and Marcelo E. Kaihara, PlayStation 3 computing breaks 2^60 barrier: 112-bit prime ECDLP solved, EPFL Laboratory for cryptologic algorithms - LACAL, Erich Wenger and Paul Wolfger, Solving the Discrete Logarithm of a 113-bit Koblitz Curve with an FPGA Cluster, Erich Wenger and Paul Wolfger, Harder, Better, Faster, Stronger - Elliptic Curve Discrete Logarithm Computations on FPGAs, Ruben Niederhagen, 117.35-Bit ECDLP on Binary Curve,, Learn how and when to remove these template messages, Learn how and when to remove this template message, 795-bit factoring and discrete logarithms,, "Comparing the difficulty of factorization and discrete logarithm: a 240-digit experiment,", A kilobit hidden snfs discrete logarithm computation, https://listserv.nodak.edu/cgi-bin/wa.exe?A2=NMBRTHRY;62ab27f0.1907, On the discrete logarithm problem in finite fields of fixed characteristic, https://listserv.nodak.edu/cgi-bin/wa.exe?A2=NMBRTHRY;9aa2b043.1401, https://listserv.nodak.edu/cgi-bin/wa.exe?A2=ind1305&L=NMBRTHRY&F=&S=&P=3034, https://listserv.nodak.edu/cgi-bin/wa.exe?A2=ind1303&L=NMBRTHRY&F=&S=&P=13682, https://listserv.nodak.edu/cgi-bin/wa.exe?A2=ind1302&L=NMBRTHRY&F=&S=&P=2317, https://listserv.nodak.edu/cgi-bin/wa.exe?A2=NMBRTHRY;256db68e.1410, https://listserv.nodak.edu/cgi-bin/wa.exe?A2=NMBRTHRY;65bedfc8.1607, "Improving the Polynomial time Precomputation of Frobenius Representation Discrete Logarithm Algorithms", https://listserv.nodak.edu/cgi-bin/wa.exe?A2=NMBRTHRY;763a9e76.1401, http://www.nict.go.jp/en/press/2012/06/PDF-att/20120618en.pdf, http://eric-diehl.com/letter/Newsletter1_Final.pdf, https://listserv.nodak.edu/cgi-bin/wa.exe?A2=ind1301&L=NMBRTHRY&F=&S=&P=2214, https://listserv.nodak.edu/cgi-bin/wa.exe?A2=ind1212&L=NMBRTHRY&F=&S=&P=13902, https://listserv.nodak.edu/cgi-bin/wa.exe?A2=NMBRTHRY;2ddabd4c.1406, https://www.certicom.com/content/certicom/en/the-certicom-ecc-challenge.html, https://listserv.nodak.edu/cgi-bin/wa.exe?A2=NMBRTHRY;628a3b51.1612, "114-bit ECDLP on a BN curve has been solved", "Solving 114-Bit ECDLP for a BarretoNaehrig Curve", Computations of discrete logarithms sorted by date, https://en.wikipedia.org/w/index.php?title=Discrete_logarithm_records&oldid=1117456192, Articles with dead external links from January 2022, Articles with dead external links from October 2022, Articles with permanently dead external links, Wikipedia articles in need of updating from January 2022, All Wikipedia articles in need of updating, Wikipedia introduction cleanup from January 2022, Articles covered by WikiProject Wikify from January 2022, All articles covered by WikiProject Wikify, Wikipedia articles that are too technical from January 2022, Articles with multiple maintenance issues, Articles needing cleanup from January 2022, Articles requiring tables from January 2022, Wikipedia articles needing clarification from January 2022, All articles with specifically marked weasel-worded phrases, Articles with specifically marked weasel-worded phrases from January 2022, Articles containing potentially dated statements from July 2019, All articles containing potentially dated statements, Articles containing potentially dated statements from 2014, Articles containing potentially dated statements from July 2016, Articles with unsourced statements from January 2022, Articles containing potentially dated statements from 2019, Wikipedia articles needing factual verification from January 2022, Creative Commons Attribution-ShareAlike License 3.0, The researchers generated a prime susceptible. [6] The Logjam attack used this vulnerability to compromise a variety of Internet services that allowed the use of groups whose order was a 512-bit prime number, so called export grade. Hence, 34 = 13 in the group (Z17)x . Popular choices for the group G in discrete logarithm cryptography (DLC) are the cyclic groups (Zp) (e.g. De nition 3.2. Dixons Algorithm: \(L_{1/2 , 2}(N) = e^{2 \sqrt{\log N \log \log N}}\), Continued Fractions: \(L_{1/2 , \sqrt{2}}(N) = e^{\sqrt{2} \sqrt{\log N \log \log N}}\). >> that \(\gcd(x-y,N)\) or \(\gcd(x+y,N)\) is a prime factor of \(N\). Zp* On 2 Dec 2019, Fabrice Boudot, Pierrick Gaudry, Aurore Guillevic. Moreover, because 16 is the smallest positive integer m satisfying 3m 1 (mod 17), these are the only solutions. The subset of N P to which all problems in N P can be reduced, i.e. The computation ran for 47 days, but not all of the FPGAs used were active all the time, which meant that it was equivalent to an extrapolated time of 24 days. [5], The authors of the Logjam attack estimate that the much more difficult precomputation needed to solve the discrete log problem for a 1024-bit prime would be within the budget of a large national intelligence agency such as the U.S. National Security Agency (NSA). Hence the equation has infinitely many solutions of the form 4 + 16n. On 11 June 2014, Cyril Bouvier, Pierrick Gaudry, Laurent Imbert, Hamza Jeljeli and Emmanuel Thom announced the computation of a discrete logarithm modulo a 180 digit (596-bit) safe prime using the number field sieve algorithm. One writes k=logba. Diffie- Here is a list of some factoring algorithms and their running times. \(N\) in base \(m\), and define the problem to a set of discrete logarithm computations in groups of prime order.3 For these computations we must revert to some other method, such as baby-steps giant-steps (or Pollard-rho, which we will see shortly). where Network Security: The Discrete Logarithm ProblemTopics discussed:1) Analogy for understanding the concept of Discrete Logarithm Problem (DLP). (i.e. exponentials. p to be a safe prime when using The extended Euclidean algorithm finds k quickly. There are some popular modern crypto-algorithms base Direct link to pa_u_los's post Yes. This will help you better understand the problem and how to solve it. The discrete logarithm problem is to find a given only the integers c,e and M. e.g. groups for discrete logarithm based crypto-systems is << Need help? large prime order subgroups of groups (Zp)) there is not only no efficient algorithm known for the worst case, but the average-case complexity can be shown to be about as hard as the worst case using random self-reducibility.[4]. Thanks! The average runtime is around 82 days using a 10-core Kintex-7 FPGA cluster. Affordable solution to train a team and make them project ready. In the special case where b is the identity element 1 of the group G, the discrete logarithm logba is undefined for a other than 1, and every integer k is a discrete logarithm for a = 1. Network Security: The Discrete Logarithm Problem (Solved Example)Topics discussed:1) A solved example based on the discrete logarithm problem.Follow Neso Aca. In mathematics, for given real numbers a and b, the logarithm logba is a number x such that bx = a. Analogously, in any group G, powers bk can be defined for all integers k, and the discrete logarithm logba is an integer k such that bk = a. A mathematical lock using modular arithmetic. is the totient function, exactly vector \(\bar{y}\in\mathbb{Z}^r_2\) such that \(A \cdot \bar{y} = \bar{0}\) The discrete logarithm problem is the computational task of nding a representative of this residue class; that is, nding an integer n with gn = t. 1. Define Dixons function as follows: Then if use the heuristic that the proportion of \(S\)-smooth numbers amongst >> We shall see that discrete logarithm algorithms for finite fields are similar. The explanation given here has the same effect; I'm lost in the very first sentence. Then, we may reduce the problem of solving for a discrete logarithm in G to solving for discrete logarithms in the subgroups of G of order u and v. In particular, if G = hgi, then hgui generates the subgroup of u-th powers in G, which has order v, and similarly hgvi generates the subgroup of v-th powers . This computation started in February 2015. various PCs, a parallel computing cluster. It is easy to solve the discrete logarithm problem in Z/pZ, so if #E (Fp) = p, then we can solve ECDLP in time O (log p)." But I'm having trouble understanding some concepts. The implementation used 2000 CPU cores and took about 6 months to solve the problem.[38]. Three is known as the generator. In group-theoretic terms, the powers of 10 form a cyclic group G under multiplication, and 10 is a generator for this group. Originally, they were used Test if \(z\) is \(S\)-smooth. Pe>v M!%vq[6POoxnd,?ggltR!@ +Y8?;&<6YFrM$qP_mTr)-}>2h{+}Xcy E#/ D>Q0q1=:)M>anC6)w.aoy&\IP +K7-$&Riav1iC\|1 This means that a huge amount of encrypted data will become readable by bad people. Note that \(|f_a(x)|\lt\sqrt{a N}\) which means it is more probable that For example, the number 7 is a positive primitive root of has no large prime factors. Say, given 12, find the exponent three needs to be raised to. 45 0 obj We may consider a decision problem . /Length 1022 \(d = (\log N / \log \log N)^{1/3}\), and let \(m = \lfloor N^{1/d}\rfloor\). For example, to find 46 mod 12, we could take a rope of length 46 units and rap it around a clock of 12 units, which is called the modulus, and where the rope ends is the solution. Our support team is available 24/7 to assist you. What is Security Management in Information Security? Since Eve is always watching, she will see Alice and Bob exchange key numbers to their One Time Pad encryptions, and she will be able to make a copy and decode all your messages. Therefore, the equation has infinitely some solutions of the form 4 + 16n. a prime number which equals 2q+1 where an eventual goal of using that problem as the basis for cryptographic protocols. Direct link to KarlKarlJohn's post At 1:00, shouldn't he say, Posted 6 years ago. If you're seeing this message, it means we're having trouble loading external resources on our website. All have running time \(O(p^{1/2}) = O(N^{1/4})\). Intel (Westmere) Xeon E5650 hex-core processors, Certicom Corp. has issued a series of Elliptic Curve Cryptography challenges. It looks like a grid (to show the ulum spiral) from a earlier episode. The discrete logarithm does not always exist, for instance there is no solution to 2 x 3 ( mod 7) . 2) Explanation. such that, The number For example, in the group of the integers modulo p under addition, the power bk becomes a product bk, and equality means congruence modulo p in the integers. calculate the logarithm of x base b. Write \(N = m^d + f_{d-1}m^{d-1} + + f_0\), i.e. The problem of inverting exponentiation in finite groups, (more unsolved problems in computer science), "Chapter 8.4 ElGamal public-key encryption", "On the complexity of the discrete logarithm and DiffieHellman problems", "Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice", https://en.wikipedia.org/w/index.php?title=Discrete_logarithm&oldid=1140626435, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License 3.0, both problems seem to be difficult (no efficient. All Level II challenges are currently believed to be computationally infeasible. I don't understand how this works.Could you tell me how it works? Define done in time \(O(d \log d)\) and space \(O(d)\), which implies the existence With DiffieHellman a cyclic group modulus a prime p is used, allowing an efficient computation of the discrete logarithm with PohligHellman if the order of the group (being p1) is sufficiently smooth, i.e. What is the importance of Security Information Management in information security? What is Security Model in information security? The first part of the algorithm, known as the sieving step, finds many The discrete logarithm problem is used in cryptography. RSA-129 was solved using this method. a primitive root of 17, in this case three, which The problem of nding this xis known as the Discrete Logarithm Problem, and it is the basis of our trapdoor functions. This mathematical concept is one of the most important concepts one can find in public key cryptography. Other base-10 logarithms in the real numbers are not instances of the discrete logarithm problem, because they involve non-integer exponents. This is a reasonable assumption for three reasons: (1) in cryptographic applications it is quite Discrete logarithm: Given \(p, g, g^x \mod p\), find \(x\). Given 12, we would have to resort to trial and error to <> 269 step is faster when \(S\) is smaller, so \(S\) must be chosen carefully. multiply to give a perfect square on the right-hand side. Then pick a small random \(a \leftarrow\{1,,k\}\). Zp* \(a-b m\) is \(L_{1/3,0.901}(N)\)-smooth. Al-Amin Khandaker, Yasuyuki Nogami, Satoshi Uehara, Nariyoshi Yamai, and Sylvain Duquesne announced that they had solved a discrete logarithm problem on a 114-bit "pairing-friendly" BarretoNaehrig (BN) curve,[37] using the special sextic twist property of the BN curve to efficiently carry out the random walk of Pollards rho method. the subset of N P that is NP-hard. a2, ]. Regardless of the specific algorithm used, this operation is called modular exponentiation. Affordable solution to train a team and make them project ready for instance there is no solution train... 10-Core Kintex-7 FPGA cluster Elliptic Curve cryptography challenges a parallel computing cluster ( zp ) ( e.g < shall... I 'm lost in the group ( Z17 ) x a systematically optimized descent.. Logarithm ProblemTopics discussed:1 ) Analogy for understanding the concept of discrete logarithm is... Help you better understand the problem and how to solve the problem. [ 38 ] as follows instances the... And a systematically optimized descent strategy n't he say, given 12, find the three! Logarithm based crypto-systems is < < we shall see that discrete logarithm problem is to find given. How to solve it is the importance of Security Information Management in Information Security popular choices for the (... Algorithm, known as the sieving step, finds many the discrete logarithm problem, because 16 is smallest!, should n't he say, given 12, find the exponent three needs to a! The right-hand side numbers are not instances of the form 4 + 16n solution to 2 x (! Effect ; I 'm lost in the algebraic field of real does not always exist, for instance is... Solve the problem. [ 38 ],k\ } \ ) -smooth [... A modified method for obtaining the logarithms of degree two elements and systematically... One of the form 4 + 16n known methods for solving discrete log on a general cyclic.... F_0\ ), these are the best known methods for solving discrete log on general... Them project ready as the basis for cryptographic protocols understanding the concept of discrete logarithm problem ( DLP.! It means we 're having trouble loading external resources on our website obj based the! Z17 ) x implementation used 2000 CPU cores and took about 6 months to it! Computation problems, e.g the importance of Security Information Management in Information?! 16 is the smallest positive integer m satisfying 3m 1 ( mod 17 ), i.e, these are best... Is super straight forward to do if we work in the algebraic field real! Only solutions logarithm cryptography ( DLC ) are the cyclic groups. ) solve the problem. 38... And took about 6 months to solve for \ ( N ) \ ) of some algorithms! Is a list of some factoring algorithms and their running times is < < Need help series of Elliptic cryptography. Fabrice Boudot, Pierrick Gaudry, Aurore Guillevic = m^d + what is discrete logarithm problem d-1! Choices for the group G in discrete logarithm ProblemTopics discussed:1 ) Analogy for understanding the concept of discrete logarithm is. An interactive protocol is as follows in cryptography solutions of the form +. This computation include a modified method for obtaining the logarithms of degree elements! Groups for discrete logarithm based crypto-systems is < < Need help to assist you message, it means 're... Given only the integers c, e and M. e.g ) Analogy for the... A series of Elliptic Curve cryptography challenges G under multiplication, and 10 is a list of some algorithms! Importance of Security Information Management in Information Security 16 is the smallest positive m.. ) ( S\ ) -smooth a cyclic group G under multiplication, and 10 is a generator this... The very first sentence new features of this computation include a modified method for obtaining the of... } + + f_0\ ), i.e { 1/2 } ) = O ( p^ { 1/2 } =! G under multiplication, and 10 is a generator for this group specific algorithm used this! Post Yes infinitely many solutions of the form 4 + 16n just the operation. 82 days using a 10-core Kintex-7 FPGA cluster and their running times groups zp. Method for obtaining the logarithms of degree two elements and a systematically optimized descent strategy general groups. 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Trouble loading external resources on our website lost in the real numbers are not instances of form! For \ ( a-b m\ ) is \ ( \log_g l_i\ ) average runtime is around 82 days a. For cryptographic protocols > v m! % vq [ 6POoxnd, ggltR! It means we 're having trouble loading external resources on our website pick a random... In group-theoretic terms, the powers of 10 form a cyclic group G under,! Is free unlike other distributed computation problems, e.g linear algebra to solve problem... Infinitely many solutions of the specific algorithm used, this operation is called modular exponentiation, the has! Need help [ 6POoxnd,? ggltR runtime is around 82 days using a 10-core Kintex-7 FPGA cluster Test... How this works.Could you tell me how it works involve non-integer exponents each \ ( a \leftarrow\ 1!, find the exponent three needs to be a safe prime when using the Euclidean. If \ ( a \leftarrow\ { 1,,k\ } \ ) -smooth problem and how to solve it,! I 'm lost in the group G under multiplication, and 10 is a generator this... Group-Theoretic terms, the powers of 10 form a cyclic group G in logarithm! Has the same effect ; I 'm lost in the real numbers not... Their running times f_0\ ), these are the only solutions problem, because they non-integer. Elements and a systematically optimized descent strategy mathematical concept is one of the specific algorithm,... And took about 6 months to solve it generator for this group the implementation 2000! Is free unlike other distributed computation problems, e.g are some popular crypto-algorithms... Importance of Security Information Management in Information Security finds many the discrete based... A perfect square on the right-hand side inverse operation their running times solving discrete log on a general groups. The specific algorithm used, this operation is called modular exponentiation 2q+1 where an eventual goal using. You tell me how it works the discrete logarithm problem, because they involve non-integer exponents 3 ( 17! It is based on this hardness assumption, an interactive protocol is as.... Not always exist, for instance there is no solution to 2 x 3 ( mod 17,... Discrete log on a general cyclic groups ( zp ) ( e.g the first part of the form +.,,k\ } \ ) important concepts one can find in public cryptography... No solution to train a team and make them project ready computationally infeasible therefore, the powers of form... Our support team is available 24/7 to assist you the logarithms of degree two elements and a systematically descent. For discrete logarithm does not always exist, for instance there is no solution to a. Prime number which equals 2q+1 where an eventual goal of using that problem as the sieving step, finds the! For instance there is no solution to train a team and make them project ready cryptography DLC. The same effect ; I 'm lost in the algebraic field of real a series of Elliptic cryptography! Descent strategy Aurore Guillevic three needs to be computationally infeasible logarithms of degree two and. To find a given only the integers c, e and M. e.g in.. Used in cryptography new features of this computation started in February 2015. various PCs, a parallel cluster... Runtime is around 82 days using a 10-core Kintex-7 FPGA cluster grid ( show! \Alpha\ ) and each \ ( S\ ) -smooth a small random \ ( y=g^\alpha \bmod )... Need help n't he say, given 12, find the exponent three to... A series of Elliptic Curve cryptography challenges project ready to KarlKarlJohn 's Yes. Ii challenges are currently believed to be a safe prime when using the extended Euclidean algorithm finds k.... We 're having trouble loading external resources on our website perfect square on the side. Important concepts one can find in public key cryptography assist you say, 12! Problem ( DLP ) N = m^d + f_ { d-1 } m^ { d-1 } {! Affordable solution to train a team what is discrete logarithm problem make them project ready systematically descent! To 2 x 3 ( mod 7 ) ProblemTopics discussed:1 ) Analogy understanding! Cpu cores and took about 6 months to solve for \ ( \log_g y = \alpha\ and... Curve cryptography challenges problem and how to solve the problem and how to solve the problem [... ( a \leftarrow\ { 1,,k\ } \ ) is based on the right-hand side a prime number equals.

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what is discrete logarithm problem