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authorThomas Voss <mail@thomasvoss.com> 2024-11-27 20:54:24 +0100
committerThomas Voss <mail@thomasvoss.com> 2024-11-27 20:54:24 +0100
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+Independent Submission M. Lochter
+Request for Comments: 5639 BSI
+Category: Informational J. Merkle
+ISSN: 2070-1721 secunet Security Networks
+ March 2010
+
+
+ Elliptic Curve Cryptography (ECC) Brainpool Standard
+ Curves and Curve Generation
+
+Abstract
+
+ This memo proposes several elliptic curve domain parameters over
+ finite prime fields for use in cryptographic applications. The
+ domain parameters are consistent with the relevant international
+ standards, and can be used in X.509 certificates and certificate
+ revocation lists (CRLs), for Internet Key Exchange (IKE), Transport
+ Layer Security (TLS), XML signatures, and all applications or
+ protocols based on the cryptographic message syntax (CMS).
+
+Status of This Memo
+
+ This document is not an Internet Standards Track specification; it is
+ published for informational purposes.
+
+ This is a contribution to the RFC Series, independently of any other
+ RFC stream. The RFC Editor has chosen to publish this document at
+ its discretion and makes no statement about its value for
+ implementation or deployment. Documents approved for publication by
+ the RFC Editor are not a candidate for any level of Internet
+ Standard; see Section 2 of RFC 5741.
+
+ Information about the current status of this document, any errata,
+ and how to provide feedback on it may be obtained at
+ http://www.rfc-editor.org/info/rfc5639.
+
+Copyright Notice
+
+ Copyright (c) 2010 IETF Trust and the persons identified as the
+ document authors. All rights reserved.
+
+ This document is subject to BCP 78 and the IETF Trust's Legal
+ Provisions Relating to IETF Documents
+ (http://trustee.ietf.org/license-info) in effect on the date of
+ publication of this document. Please review these documents
+ carefully, as they describe your rights and restrictions with respect
+ to this document.
+
+
+
+
+Lochter & Merkle Informational [Page 1]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+Table of Contents
+
+ 1. Introduction ....................................................3
+ 1.1. Scope and Relation to Other Specifications .................4
+ 1.2. Requirements Language ......................................4
+ 2. Requirements on the Elliptic Curve Domain Parameters ............4
+ 2.1. Security Requirements ......................................5
+ 2.2. Technical Requirements .....................................6
+ 3. Domain Parameter Specification ..................................8
+ 3.1. Domain Parameters for 160-Bit Curves .......................8
+ 3.2. Domain Parameters for 192-Bit Curves .......................9
+ 3.3. Domain Parameters for 224-Bit Curves ......................10
+ 3.4. Domain Parameters for 256-Bit Curves ......................11
+ 3.5. Domain Parameters for 320-Bit Curves ......................12
+ 3.6. Domain Parameters for 384-Bit Curves ......................13
+ 3.7. Domain Parameters for 512-Bit Curves ......................14
+ 4. Object Identifiers and ASN.1 Syntax ............................15
+ 4.1. Object Identifiers ........................................15
+ 4.2. ASN.1 Syntax for Usage with X.509 Certificates ............16
+ 5. Security Considerations ........................................17
+ 6. Intellectual Property Rights ...................................18
+ 7. References .....................................................18
+ 7.1. Normative References ......................................18
+ 7.2. Informative References ....................................19
+ Appendix A. Pseudo-Random Generation of Parameters ................22
+ A.1. Generation of Prime Numbers ................................22
+ A.2. Generation of Pseudo-Random Curves .........................24
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Lochter & Merkle Informational [Page 2]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+1. Introduction
+
+ Although several standards for elliptic curves and domain parameters
+ exist (e.g., [ANSI1], [FIPS], or [SEC2]), some major issues have
+ still not been addressed:
+
+ o Not all parameters have been generated in a verifiably pseudo-
+ random way. In particular, the seeds from which the curve
+ parameters were derived have been chosen ad hoc, leaving out an
+ essential part of the security proof.
+
+ o The primes selected for the base fields have a very special form
+ facilitating efficient implementation. This does not only
+ contradict the approach of pseudo-random parameters, but also
+ increases the risk of implementations violating one of the
+ numerous patents for fast modular arithmetic with special primes.
+
+ o No proofs are provided that the proposed parameters do not belong
+ to those classes of parameters that are susceptible to
+ cryptanalytic attacks with sub-exponential complexity.
+
+ o Recent research results seem to indicate a potential for new
+ attacks on elliptic curve cryptosystems. At least for
+ applications with the highest security demands or under
+ circumstances that complicate a change of parameters in response
+ to new attacks, the inclusion of a corresponding security
+ requirement for domain parameters (the class group condition, see
+ Section 2) is justified.
+
+ o Some of the proposed subgroups have a non-trivial cofactor, which
+ demands additional checks by cryptographic applications to prevent
+ small subgroup attacks (see [ANSI1] or [SEC1]).
+
+ o The domain parameters specified do not cover all bit lengths that
+ correspond to the commonly used key lengths for symmetric
+ cryptographic algorithms. In particular, there is no 512-bit
+ curve defined, but only one with a 521-bit length, which may be
+ disadvantageous for some implementations.
+
+ Furthermore, many of the parameters specified by the existing
+ standards are identical (see [SEC2] for a comparison). Thus, there
+ is still a need for additional elliptic curve domain parameters that
+ overcome the above limitations.
+
+
+
+
+
+
+
+
+Lochter & Merkle Informational [Page 3]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+1.1. Scope and Relation to Other Specifications
+
+ This RFC specifies elliptic curve domain parameters over prime fields
+ GF(p) with p having a length of 160, 192, 224, 256, 320, 384, and 512
+ bits. These parameters were generated in a pseudo-random, yet
+ completely systematic and reproducible, way and have been verified to
+ resist current cryptanalytic approaches. The parameters are
+ compliant with ANSI X9.62 [ANSI1] and ANSI X9.63 [ANSI2], ISO/IEC
+ 14888 [ISO1] and ISO/IEC 15946 [ISO2], ETSI TS 102 176-1 [ETSI], as
+ well as with FIPS-186-2 [FIPS], and the Efficient Cryptography Group
+ (SECG) specifications ([SEC1] and [SEC2]).
+
+ Furthermore, this document identifies the security and implementation
+ requirements for the parameters, and describes the methods used for
+ the pseudo-random generation of the parameters.
+
+ Finally, this RFC defines ASN.1 object identifiers for all elliptic
+ curve domain parameter sets specified herein, e.g., for use in X.509
+ certificates.
+
+ This document does neither address the cryptographic algorithms to be
+ used with the specified parameters nor their application in other
+ standards. However, it is consistent with the following RFCs that
+ specify the usage of elliptic curve cryptography in protocols and
+ applications:
+
+ o [RFC5753] for the cryptographic message syntax (CMS)
+
+ o [RFC3279] and [RFC5480] for X.509 certificates and CRLs
+
+ o [RFC4050] for XML signatures
+
+ o [RFC4492] for TLS
+
+ o [RFC4754] for IKE
+
+1.2. Requirements Language
+
+ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+ "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
+ document are to be interpreted as described in RFC 2119 [RFC2119].
+
+2. Requirements on the Elliptic Curve Domain Parameters
+
+ Throughout this memo, let p > 3 be a prime and GF(p) a finite field
+ (sometimes also referred to as Galois Field or GF(p)) with p
+ elements. For given A and B with non-zero 4*A^3 + 27*B^2 mod p, the
+ set of solutions (x,y) for the equation E: y^2 = x^3 + A*x + B mod p
+
+
+
+Lochter & Merkle Informational [Page 4]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ over GF(p) together with a neutral element O and well-defined laws
+ for addition and inversion define a group E(GF(p)) -- the group of
+ GF(p) rational points on E. Typically, for cryptographic
+ applications, an element G of prime order q is chosen in E(GF(p)).
+
+ A comprehensive introduction to elliptic curve cryptography can be
+ found in [CFDA] and [BSS].
+
+ Note 1: We choose {0,...,p-1} as a set of representatives for the
+ elements of GF(p). This choice induces a natural ordering on GF(p).
+
+2.1. Security Requirements
+
+ The following security requirements are either motivated by known
+ cryptographic analysis or aim to enhance trust in the recommended
+ curves. As this specification aims at a particularly high level of
+ security, a restrictive position is taken here. Nevertheless, it may
+ be sensible to slightly deviate from these requirements for certain
+ applications (e.g., in order to achieve higher computational
+ performance). More details on requirements for cryptographically
+ strong elliptic curves can be found in [CFDA] and [BSS].
+
+ 1. Immunity to attacks using the Weil or Tate Pairing. These
+ attacks allow the embedding of the cyclic subgroup generated by G
+ into the group of units of a degree-l extension GF(p^l) of GF(p),
+ where sub-exponential attacks on the discrete logarithm problem
+ (DLP) exist. Here we have l = min{t | q divides p^t - 1}, i.e.,
+ l is the order of p mod q. By Fermat's Little Theorem, l divides
+ q-1. We require (q-1)/l < 100, which means that l is close to
+ the maximum possible value. This requirement is considerably
+ stronger than those of [SEC2] and [ANSI2] and also excludes
+ supersingular curves, as those are the curves of order p+1.
+
+ 2. The trace is not equal to one. Trace one curves (or anomalous
+ curves) are curves with #E(GF(p)) = p. Satoh and Araki [SA],
+ Semaev [Sem], and Smart [Sma] independently proposed efficient
+ solutions to the elliptic curve discrete logarithm problem
+ (ECDLP) on trace one curves. Note that these curves are also
+ excluded by requirement 5 of Section 2.2.
+
+ 3. Large class number. The class number of the maximal order of the
+ quotient field of the endomorphism ring End(E) of E is larger
+ than 10^7. Generally, E cannot be "lifted" to a curve E' over an
+ algebraic number field L with End(E) = End(E') unless the degree
+ of L over the rationals is larger than the class number of
+ End(E). Although there are no efficient attacks exploiting a
+ small class number, recent work ([JMV] and [HR]) also may be seen
+ as argument for the class number condition.
+
+
+
+Lochter & Merkle Informational [Page 5]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ 4. Prime group order. The group order #E(GF(p)) shall be a prime
+ number in order to counter small-subgroup attacks (see [HMV]).
+ Therefore, all groups proposed in this RFC have cofactor 1. Note
+ that curves with prime order have no point of order 2 and
+ therefore no point with y-coordinate 0.
+
+ 5. Verifiably pseudo-random. The elliptic curve domain parameters
+ shall be generated in a pseudo-random manner using seeds that are
+ generated in a systematic and comprehensive way. The methods by
+ which the parameters have been obtained are explained in Appendix
+ A.
+
+ 6. Proof of security. For all curves, a proof should be given that
+ all security requirements are met. These proofs are provided in
+ [EBP].
+
+ In [BG], attacks are described that apply to elliptic curve domain
+ parameters where q-1 has a factor u in the order of q^(1/3).
+ However, the circumstances under which these attacks are applicable
+ can be avoided in most applications. Therefore, no corresponding
+ security requirement is stated here. However, it is highly
+ recommended that developers verify the security of their
+ implementations against this kind of attack.
+
+2.2. Technical Requirements
+
+ Commercial demands and experience with existing implementations lead
+ to the following technical requirements for the elliptic curve domain
+ parameters.
+
+ 1. For each of the bit lengths 160, 192, 224, 256, 320, 384, and
+ 512, one curve shall be proposed. This requirement follows from
+ the need for curves providing different levels of security that
+ are appropriate for the underlying symmetric algorithms. The
+ existing standards specify a 521-bit curve instead of a 512-bit
+ curve.
+
+ 2. The prime number p shall be congruent 3 mod 4. This requirement
+ allows efficient point compression: one method for the
+ transmission of curve points P=(x,y) is to transmit only x and
+ the least significant bit LSB(y) of y. For p = 3 mod 4, we get
+ (y^2)^((p+1)/4) = y*y^((p-1)/2), which is either y or -y by
+ Fermat's Little Theorem; hence, y can be computed very
+ efficiently using the curve equation. This requirement is not
+ always met by the parameters defined in existing standards.
+
+
+
+
+
+
+Lochter & Merkle Informational [Page 6]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ 3. The curves shall be GF(p)-isomorphic to a curve E': y^2 = x^3 +
+ A'*x + B' mod p with A' = -3 mod p. This property permits the
+ use of the arithmetical advantages of curves with A = -3, as
+ shown by Brier and Joyce [BJ]. For p = 3 mod 4, approximately
+ half of the isomorphism classes of elliptic curves over GF(p)
+ contain a curve E' with A' = -3 mod p. Precisely, if a curve is
+ given by E: y^2 = x^3 + A*x + B mod p with -3 = A*u^4 being
+ solvable in GF(p) and u=Z is a solution to this equation, then
+ the requirement is fulfilled by means of the quadratic twist E':
+ y^2 = x^3 + Z^4*A*x + Z^6*B mod p, and the GF(p)-isomorphism is
+ given by F(x,y) := (x*Z^2, y*Z^3). Due to this isomorphism,
+ E(GF(p)) and E'(GF(p)) have the same number of points, share the
+ same algebraic structure, and hence offer the same level of
+ security. This constraint has also been used by [SEC2] and
+ [FIPS].
+
+ 4. The prime p must not be of any special form; this requirement is
+ met by a verifiably pseudo-random generation of the parameters
+ (see requirement 5 in Section 2.1). Although parameters
+ specified by existing standards do not meet this requirement, the
+ need for such curves over (pseudo-)randomly chosen fields has
+ already been foreseen by the Standards for Efficient Cryptography
+ Group (SECG), see [SEC2].
+
+ 5. #E(GF(p)) < p. As a consequence of the Hasse-Weil Theorem, the
+ number of points #E(GF(p)) may be greater than the characteristic
+ p of the prime field GF(p). In some cases, even the bit-length
+ of #E(GF(p)) can exceed the bit-length of p. To avoid overruns
+ in implementations, we require that #E(GF(p)) < p. In order to
+ thwart attacks on digital signature schemes, some authors propose
+ to use q > p, but the attacks described, e.g., in [BRS], appear
+ infeasible in a well-designed Public Key Infrastructure (PKI).
+
+ 6. B shall be a non-square mod p. Otherwise, the compressed
+ representations of the curve-points (0,0) and (0,X), with X being
+ the square root of B with a least significant bit of 0, would be
+ identical. As there are implementations of elliptic curves that
+ encode the point at infinity as (0,0), we try to avoid
+ ambiguities. Note that this condition is stable under quadratic
+ twists as described in condition 3 above. Condition 6 makes the
+ attack described in [G] impossible. It can therefore also be
+ seen as a security requirement. This constraint has not been
+ specified by existing standards.
+
+
+
+
+
+
+
+
+Lochter & Merkle Informational [Page 7]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+3. Domain Parameter Specification
+
+ In this section, the elliptic curve domain parameters proposed are
+ specified in the following way.
+
+ For all curves, an ID is given by which it can be referenced.
+
+ p is the prime specifying the base field.
+
+ A and B are the coefficients of the equation y^2 = x^3 + A*x + B
+ mod p defining the elliptic curve.
+
+ G = (x,y) is the base point, i.e., a point in E of prime order,
+ with x and y being its x- and y-coordinates, respectively.
+
+ q is the prime order of the group generated by G.
+
+ h is the cofactor of G in E, i.e., #E(GF(p))/q.
+
+ For the twisted curve, we also give the coefficient Z that defines
+ the isomorphism F (see requirement 3 in Section 2.2).
+
+ The methods for the generation of the parameters are given in
+ Appendix A. Proofs for the fulfillment of the security requirements
+ specified in Section 2.1 are given in [EBP].
+
+3.1. Domain Parameters for 160-Bit Curves
+
+ Curve-ID: brainpoolP160r1
+
+ p = E95E4A5F737059DC60DFC7AD95B3D8139515620F
+
+ A = 340E7BE2A280EB74E2BE61BADA745D97E8F7C300
+
+ B = 1E589A8595423412134FAA2DBDEC95C8D8675E58
+
+ x = BED5AF16EA3F6A4F62938C4631EB5AF7BDBCDBC3
+
+ y = 1667CB477A1A8EC338F94741669C976316DA6321
+
+ q = E95E4A5F737059DC60DF5991D45029409E60FC09
+
+ h = 1
+
+
+
+
+
+
+
+
+Lochter & Merkle Informational [Page 8]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ #Twisted curve
+
+ Curve-ID: brainpoolP160t1
+
+ Z = 24DBFF5DEC9B986BBFE5295A29BFBAE45E0F5D0B
+
+ A = E95E4A5F737059DC60DFC7AD95B3D8139515620C
+
+ B = 7A556B6DAE535B7B51ED2C4D7DAA7A0B5C55F380
+
+ x = B199B13B9B34EFC1397E64BAEB05ACC265FF2378
+
+ y = ADD6718B7C7C1961F0991B842443772152C9E0AD
+
+ q = E95E4A5F737059DC60DF5991D45029409E60FC09
+
+ h = 1
+
+3.2. Domain Parameters for 192-Bit Curves
+
+ Curve-ID: brainpoolP192r1
+
+ p = C302F41D932A36CDA7A3463093D18DB78FCE476DE1A86297
+
+ A = 6A91174076B1E0E19C39C031FE8685C1CAE040E5C69A28EF
+
+ B = 469A28EF7C28CCA3DC721D044F4496BCCA7EF4146FBF25C9
+
+ x = C0A0647EAAB6A48753B033C56CB0F0900A2F5C4853375FD6
+
+ y = 14B690866ABD5BB88B5F4828C1490002E6773FA2FA299B8F
+
+ q = C302F41D932A36CDA7A3462F9E9E916B5BE8F1029AC4ACC1
+
+ h = 1
+
+ #Twisted curve
+
+ Curve-ID: brainpoolP192t1
+
+ Z = 1B6F5CC8DB4DC7AF19458A9CB80DC2295E5EB9C3732104CB
+
+ A = C302F41D932A36CDA7A3463093D18DB78FCE476DE1A86294
+
+ B = 13D56FFAEC78681E68F9DEB43B35BEC2FB68542E27897B79
+
+ x = 3AE9E58C82F63C30282E1FE7BBF43FA72C446AF6F4618129
+
+
+
+
+Lochter & Merkle Informational [Page 9]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ y = 097E2C5667C2223A902AB5CA449D0084B7E5B3DE7CCC01C9
+
+ q = C302F41D932A36CDA7A3462F9E9E916B5BE8F1029AC4ACC1
+
+ h = 1
+
+3.3. Domain Parameters for 224-Bit Curves
+
+ Curve-ID: brainpoolP224r1
+
+ p = D7C134AA264366862A18302575D1D787B09F075797DA89F57EC8C0FF
+
+ A = 68A5E62CA9CE6C1C299803A6C1530B514E182AD8B0042A59CAD29F43
+
+ B = 2580F63CCFE44138870713B1A92369E33E2135D266DBB372386C400B
+
+ x = 0D9029AD2C7E5CF4340823B2A87DC68C9E4CE3174C1E6EFDEE12C07D
+
+ y = 58AA56F772C0726F24C6B89E4ECDAC24354B9E99CAA3F6D3761402CD
+
+ q = D7C134AA264366862A18302575D0FB98D116BC4B6DDEBCA3A5A7939F
+
+ h = 1
+
+ #Twisted curve
+
+ Curve-ID: brainpoolP224t1
+
+ Z = 2DF271E14427A346910CF7A2E6CFA7B3F484E5C2CCE1C8B730E28B3F
+
+ A = D7C134AA264366862A18302575D1D787B09F075797DA89F57EC8C0FC
+
+ B = 4B337D934104CD7BEF271BF60CED1ED20DA14C08B3BB64F18A60888D
+
+ x = 6AB1E344CE25FF3896424E7FFE14762ECB49F8928AC0C76029B4D580
+
+ y = 0374E9F5143E568CD23F3F4D7C0D4B1E41C8CC0D1C6ABD5F1A46DB4C
+
+ q = D7C134AA264366862A18302575D0FB98D116BC4B6DDEBCA3A5A7939F
+
+ h = 1
+
+
+
+
+
+
+
+
+
+
+Lochter & Merkle Informational [Page 10]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+3.4. Domain Parameters for 256-Bit Curves
+
+ Curve-ID: brainpoolP256r1
+
+ p =
+ A9FB57DBA1EEA9BC3E660A909D838D726E3BF623D52620282013481D1F6E5377
+
+ A =
+ 7D5A0975FC2C3057EEF67530417AFFE7FB8055C126DC5C6CE94A4B44F330B5D9
+
+ B =
+ 26DC5C6CE94A4B44F330B5D9BBD77CBF958416295CF7E1CE6BCCDC18FF8C07B6
+
+ x =
+ 8BD2AEB9CB7E57CB2C4B482FFC81B7AFB9DE27E1E3BD23C23A4453BD9ACE3262
+
+ y =
+ 547EF835C3DAC4FD97F8461A14611DC9C27745132DED8E545C1D54C72F046997
+
+ q =
+ A9FB57DBA1EEA9BC3E660A909D838D718C397AA3B561A6F7901E0E82974856A7
+
+ h = 1
+
+ #Twisted curve
+
+ Curve-ID: brainpoolP256t1
+
+ Z =
+ 3E2D4BD9597B58639AE7AA669CAB9837CF5CF20A2C852D10F655668DFC150EF0
+
+ A =
+ A9FB57DBA1EEA9BC3E660A909D838D726E3BF623D52620282013481D1F6E5374
+
+ B =
+ 662C61C430D84EA4FE66A7733D0B76B7BF93EBC4AF2F49256AE58101FEE92B04
+
+ x =
+ A3E8EB3CC1CFE7B7732213B23A656149AFA142C47AAFBC2B79A191562E1305F4
+
+ y =
+ 2D996C823439C56D7F7B22E14644417E69BCB6DE39D027001DABE8F35B25C9BE
+
+ q =
+ A9FB57DBA1EEA9BC3E660A909D838D718C397AA3B561A6F7901E0E82974856A7
+
+ h = 1
+
+
+
+
+Lochter & Merkle Informational [Page 11]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+3.5. Domain Parameters for 320-Bit Curves
+
+ Curve-ID: brainpoolP320r1
+
+ p = D35E472036BC4FB7E13C785ED201E065F98FCFA6F6F40DEF4F92B9EC7893EC
+ 28FCD412B1F1B32E27
+
+ A = 3EE30B568FBAB0F883CCEBD46D3F3BB8A2A73513F5EB79DA66190EB085FFA9
+ F492F375A97D860EB4
+
+ B = 520883949DFDBC42D3AD198640688A6FE13F41349554B49ACC31DCCD884539
+ 816F5EB4AC8FB1F1A6
+
+ x = 43BD7E9AFB53D8B85289BCC48EE5BFE6F20137D10A087EB6E7871E2A10A599
+ C710AF8D0D39E20611
+
+ y = 14FDD05545EC1CC8AB4093247F77275E0743FFED117182EAA9C77877AAAC6A
+ C7D35245D1692E8EE1
+
+ q = D35E472036BC4FB7E13C785ED201E065F98FCFA5B68F12A32D482EC7EE8658
+ E98691555B44C59311
+
+ h = 1
+
+ #Twisted curve
+
+ Curve-ID: brainpoolP320t1
+
+ Z = 15F75CAF668077F7E85B42EB01F0A81FF56ECD6191D55CB82B7D861458A18F
+ EFC3E5AB7496F3C7B1
+
+ A = D35E472036BC4FB7E13C785ED201E065F98FCFA6F6F40DEF4F92B9EC7893EC
+ 28FCD412B1F1B32E24
+
+ B = A7F561E038EB1ED560B3D147DB782013064C19F27ED27C6780AAF77FB8A547
+ CEB5B4FEF422340353
+
+ x = 925BE9FB01AFC6FB4D3E7D4990010F813408AB106C4F09CB7EE07868CC136F
+ FF3357F624A21BED52
+
+ y = 63BA3A7A27483EBF6671DBEF7ABB30EBEE084E58A0B077AD42A5A0989D1EE7
+ 1B1B9BC0455FB0D2C3
+
+ q = D35E472036BC4FB7E13C785ED201E065F98FCFA5B68F12A32D482EC7EE8658
+ E98691555B44C59311
+
+ h = 1
+
+
+
+
+Lochter & Merkle Informational [Page 12]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+3.6. Domain Parameters for 384-Bit Curves
+
+ Curve-ID: brainpoolP384r1
+
+ p = 8CB91E82A3386D280F5D6F7E50E641DF152F7109ED5456B412B1DA197FB711
+ 23ACD3A729901D1A71874700133107EC53
+
+ A = 7BC382C63D8C150C3C72080ACE05AFA0C2BEA28E4FB22787139165EFBA91F9
+ 0F8AA5814A503AD4EB04A8C7DD22CE2826
+
+ B = 04A8C7DD22CE28268B39B55416F0447C2FB77DE107DCD2A62E880EA53EEB62
+ D57CB4390295DBC9943AB78696FA504C11
+
+ x = 1D1C64F068CF45FFA2A63A81B7C13F6B8847A3E77EF14FE3DB7FCAFE0CBD10
+ E8E826E03436D646AAEF87B2E247D4AF1E
+
+ y = 8ABE1D7520F9C2A45CB1EB8E95CFD55262B70B29FEEC5864E19C054FF99129
+ 280E4646217791811142820341263C5315
+
+ q = 8CB91E82A3386D280F5D6F7E50E641DF152F7109ED5456B31F166E6CAC0425
+ A7CF3AB6AF6B7FC3103B883202E9046565
+
+ h = 1
+
+ #Twisted curve
+
+ Curve-ID: brainpoolP384t1
+
+ Z = 41DFE8DD399331F7166A66076734A89CD0D2BCDB7D068E44E1F378F41ECBAE
+ 97D2D63DBC87BCCDDCCC5DA39E8589291C
+
+ A = 8CB91E82A3386D280F5D6F7E50E641DF152F7109ED5456B412B1DA197FB711
+ 23ACD3A729901D1A71874700133107EC50
+
+ B = 7F519EADA7BDA81BD826DBA647910F8C4B9346ED8CCDC64E4B1ABD11756DCE
+ 1D2074AA263B88805CED70355A33B471EE
+
+ x = 18DE98B02DB9A306F2AFCD7235F72A819B80AB12EBD653172476FECD462AAB
+ FFC4FF191B946A5F54D8D0AA2F418808CC
+
+ y = 25AB056962D30651A114AFD2755AD336747F93475B7A1FCA3B88F2B6A208CC
+ FE469408584DC2B2912675BF5B9E582928
+
+ q = 8CB91E82A3386D280F5D6F7E50E641DF152F7109ED5456B31F166E6CAC0425
+ A7CF3AB6AF6B7FC3103B883202E9046565
+
+ h = 1
+
+
+
+
+Lochter & Merkle Informational [Page 13]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+3.7. Domain Parameters for 512-Bit Curves
+
+ Curve-ID: brainpoolP512r1
+
+ p = AADD9DB8DBE9C48B3FD4E6AE33C9FC07CB308DB3B3C9D20ED6639CCA703308
+ 717D4D9B009BC66842AECDA12AE6A380E62881FF2F2D82C68528AA6056583A48F3
+
+ A = 7830A3318B603B89E2327145AC234CC594CBDD8D3DF91610A83441CAEA9863
+ BC2DED5D5AA8253AA10A2EF1C98B9AC8B57F1117A72BF2C7B9E7C1AC4D77FC94CA
+
+ B = 3DF91610A83441CAEA9863BC2DED5D5AA8253AA10A2EF1C98B9AC8B57F1117
+ A72BF2C7B9E7C1AC4D77FC94CADC083E67984050B75EBAE5DD2809BD638016F723
+
+ x = 81AEE4BDD82ED9645A21322E9C4C6A9385ED9F70B5D916C1B43B62EEF4D009
+ 8EFF3B1F78E2D0D48D50D1687B93B97D5F7C6D5047406A5E688B352209BCB9F822
+
+ y = 7DDE385D566332ECC0EABFA9CF7822FDF209F70024A57B1AA000C55B881F81
+ 11B2DCDE494A5F485E5BCA4BD88A2763AED1CA2B2FA8F0540678CD1E0F3AD80892
+
+ q = AADD9DB8DBE9C48B3FD4E6AE33C9FC07CB308DB3B3C9D20ED6639CCA703308
+ 70553E5C414CA92619418661197FAC10471DB1D381085DDADDB58796829CA90069
+
+ h = 1
+
+ #Twisted curve
+
+ Curve-ID: brainpoolP512t1
+
+ Z = 12EE58E6764838B69782136F0F2D3BA06E27695716054092E60A80BEDB212B
+ 64E585D90BCE13761F85C3F1D2A64E3BE8FEA2220F01EBA5EEB0F35DBD29D922AB
+
+ A = AADD9DB8DBE9C48B3FD4E6AE33C9FC07CB308DB3B3C9D20ED6639CCA703308
+ 717D4D9B009BC66842AECDA12AE6A380E62881FF2F2D82C68528AA6056583A48F0
+
+ B = 7CBBBCF9441CFAB76E1890E46884EAE321F70C0BCB4981527897504BEC3E36
+ A62BCDFA2304976540F6450085F2DAE145C22553B465763689180EA2571867423E
+
+ x = 640ECE5C12788717B9C1BA06CBC2A6FEBA85842458C56DDE9DB1758D39C031
+ 3D82BA51735CDB3EA499AA77A7D6943A64F7A3F25FE26F06B51BAA2696FA9035DA
+
+ y = 5B534BD595F5AF0FA2C892376C84ACE1BB4E3019B71634C01131159CAE03CE
+ E9D9932184BEEF216BD71DF2DADF86A627306ECFF96DBB8BACE198B61E00F8B332
+
+ q = AADD9DB8DBE9C48B3FD4E6AE33C9FC07CB308DB3B3C9D20ED6639CCA703308
+ 70553E5C414CA92619418661197FAC10471DB1D381085DDADDB58796829CA90069
+
+ h = 1
+
+
+
+
+Lochter & Merkle Informational [Page 14]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+4. Object Identifiers and ASN.1 Syntax
+
+4.1. Object Identifiers
+
+ The root of the tree for the object identifiers defined in this
+ specification is given by:
+
+ ecStdCurvesAndGeneration OBJECT IDENTIFIER::= {iso(1)
+ identified-organization(3) teletrust(36) algorithm(3) signature-
+ algorithm(3) ecSign(2) 8}
+
+ The object identifier ellipticCurve represents the tree for domain
+ parameter sets. It has the following value:
+
+ ellipticCurve OBJECT IDENTIFIER ::= {ecStdCurvesAndGeneration 1}
+
+ The tree containing the object identifiers for each set of domain
+ parameters defined in this RFC is:
+
+ versionOne OBJECT IDENTIFIER ::= {ellipticCurve 1}
+
+ The following object identifiers represent the domain parameter sets
+ defined in this RFC:
+
+ brainpoolP160r1 OBJECT IDENTIFIER ::= {versionOne 1}
+
+ brainpoolP160t1 OBJECT IDENTIFIER ::= {versionOne 2}
+
+ brainpoolP192r1 OBJECT IDENTIFIER ::= {versionOne 3}
+
+ brainpoolP192t1 OBJECT IDENTIFIER ::= {versionOne 4}
+
+ brainpoolP224r1 OBJECT IDENTIFIER ::= {versionOne 5}
+
+ brainpoolP224t1 OBJECT IDENTIFIER ::= {versionOne 6}
+
+ brainpoolP256r1 OBJECT IDENTIFIER ::= {versionOne 7}
+
+ brainpoolP256t1 OBJECT IDENTIFIER ::= {versionOne 8}
+
+ brainpoolP320r1 OBJECT IDENTIFIER ::= {versionOne 9}
+
+ brainpoolP320t1 OBJECT IDENTIFIER ::= {versionOne 10}
+
+ brainpoolP384r1 OBJECT IDENTIFIER ::= {versionOne 11}
+
+ brainpoolP384t1 OBJECT IDENTIFIER ::= {versionOne 12}
+
+
+
+
+Lochter & Merkle Informational [Page 15]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ brainpoolP512r1 OBJECT IDENTIFIER ::= {versionOne 13}
+
+ brainpoolP512t1 OBJECT IDENTIFIER ::= {versionOne 14}
+
+4.2. ASN.1 Syntax for Usage with X.509 Certificates
+
+ The domain parameters specified in this RFC SHALL be used with X.509
+ certificates in accordance with [RFC5480]. In particular,
+
+ o the algorithm field of subjectPublicKeyInfo MUST be set to:
+
+ * id-ecPublicKey, if the algorithms that can be used with the
+ subject public key are not restricted, or
+
+ * id-ecDH to restrict the usage of the subject public key to
+ Elliptic Curve Diffie-Hellman (ECDH) key agreement, or
+
+ * id-ecMQV to restrict the usage of the subject public key to
+ Elliptic Curve Menezes-Qu-Vanstone (ECMQV) key agreement, and
+
+ o the field algorithm.parameter of subjectPublicKeyInfo MUST be of
+ type:
+
+ * namedCurve to specify the domain parameters by one of the
+ Object Identifiers (OIDs) defined in Section 4.1, or
+
+ * specifiedCurve to specify the domain parameters explicitly as
+ defined in [RFC5480], or
+
+ * implicitCurve, if the domain parameters are found in an
+ issuer's certificate.
+
+ If the domain parameters are explicitly specified using the type
+ specifiedCurve in the field algorithm.parameter of
+ subjectPublicKeyInfo, ANSI X9.62 [ANSI1] and [RFC5480] allow
+ indicating whether or not a curve and base point have been generated
+ verifiably in a pseudo-random way. Although the parameters specified
+ in Section 3 have all been generated by the pseudo-random methods
+ described in Appendix A, these algorithms deviate from those mandated
+ in ANSI X9.62, A.3.3.1. Consequently, applications following ANSI
+ X9.62 or [RFC5480] will not be able to verify the pseudo-randomness
+ of the parameters. In order to avoid rejection of the parameters,
+ the ASN.1 encoding SHOULD NOT specify that the curve or base point
+ has been generated verifiably at random. In particular,
+ certification authorities (CAs) SHOULD set the contents of
+ specifiedCurve in the following way:
+
+ o version is set to ecpVer1(1).
+
+
+
+Lochter & Merkle Informational [Page 16]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ o fieldId includes the fieldType prime-field and as parameter the
+ value p of the selected domain parameters as specified in Section
+ 3.
+
+ o curve includes the values a and b of the selected domain
+ parameters as specified in Section 3, but seed is absent.
+
+ o base is the octet string representation of the base point G of the
+ selected domain parameters as specified in Section 3.
+
+ o order is set to q of the selected domain parameters as specified
+ in Section 3.
+
+ o cofactor is set to 1.
+
+ o hash is absent.
+
+5. Security Considerations
+
+ The level of security provided by symmetric ciphers and hash
+ functions used in conjunction with the elliptic curve domain
+ parameters specified in this RFC should roughly match or exceed the
+ level provided by the domain parameters. The following table
+ indicates the minimum key sizes for symmetric ciphers and hash
+ functions providing at least (roughly) comparable security.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Lochter & Merkle Informational [Page 17]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ +--------------------+--------------------+-------------------------+
+ | elliptic curve | minimum length of | hash functions |
+ | domain parameters | symmetric keys | |
+ +--------------------+--------------------+-------------------------+
+ | brainpoolP160r1 | 80 | SHA-1, SHA-224, |
+ | | | SHA-256, SHA-384, |
+ | | | SHA-512 |
+ | | | |
+ | brainpoolP192r1 | 96 | SHA-224, SHA-256, |
+ | | | SHA-384, SHA-512 |
+ | | | |
+ | brainpoolP224r1 | 112 | SHA-224, SHA-256, |
+ | | | SHA-384, SHA-512 |
+ | | | |
+ | brainpoolP256r1 | 128 | SHA-256, SHA-384, |
+ | | | SHA-512 |
+ | | | |
+ | brainpoolP320r1 | 160 | SHA-384, SHA-512 |
+ | | | |
+ | brainpoolP384r1 | 192 | SHA-384, SHA-512 |
+ | | | |
+ | brainpoolP512r1 | 256 | SHA-512 |
+ +--------------------+--------------------+-------------------------+
+
+ Table 1
+
+ Security properties of the elliptic curve domain parameters specified
+ in this RFC are discussed in Section 2.1. Further security
+ discussions specific to elliptic curve cryptography can be found in
+ [ANSI1] and [SEC1].
+
+6. Intellectual Property Rights
+
+ The authors have no knowledge about any intellectual property rights
+ that cover the usage of the domain parameters defined herein.
+ However, readers should be aware that implementations based on these
+ domain parameters may require use of inventions covered by patent
+ rights.
+
+7. References
+
+7.1. Normative References
+
+ [ANSI1] American National Standards Institute, "Public Key
+ Cryptography For The Financial Services Industry: The
+ Elliptic Curve Digital Signature Algorithm (ECDSA)", ANSI
+ X9.62, 2005.
+
+
+
+
+Lochter & Merkle Informational [Page 18]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
+ Requirement Levels", BCP 14, RFC 2119, March 1997.
+
+ [RFC5480] Turner, S., Brown, D., Yiu, K., Housley, R., and T. Polk,
+ "Elliptic Curve Cryptography Subject Public Key
+ Information", RFC 5480, March 2009.
+
+7.2. Informative References
+
+ [ANSI2] American National Standards Institute, "Public Key
+ Cryptography For The Financial Services Industry: Key
+ Agreement and Key Transport Using The Elliptic Curve
+ Cryptography", ANSI X9.63, 2001.
+
+ [BJ] Brier, E. and M. Joyce, "Fast Multiplication on Elliptic
+ Curves through Isogenies", Applied Algebra Algebraic
+ Algorithms and Error-Correcting Codes, Lecture Notes in
+ Computer Science 2643, Springer Verlag, 2003.
+
+ [BG] Brown, J. and R. Gallant, "The Static Diffie-Hellman
+ Problem", Centre for Applied Cryptographic Research,
+ University of Waterloo, Technical Report CACR 2004-10,
+ 2005.
+
+ [BRS] Bohli, J., Roehrich, S., and R. Steinwandt, "Key
+ Substitution Attacks Revisited: Taking into Account
+ Malicious Signers", International Journal of Information
+ Security Volume 5, Issue 1, January 2006.
+
+ [BSS] Blake, I., Seroussi, G., and N. Smart, "Elliptic Curves in
+ Cryptography", Cambridge University Press, 1999.
+
+ [EBP] ECC Brainpool, "ECC Brainpool Standard Curves and Curve
+ Generation", October 2005, <http://www.ecc-brainpool.org/
+ download/Domain-parameters.pdf>.
+
+ [ETSI] European Telecommunications Standards Institute (ETSI),
+ "Algorithms and Parameters for Secure Electronic
+ Signatures, Part 1: Hash Functions and Asymmetric
+ Algorithms", TS 102 176-1, July 2005.
+
+ [FIPS] National Institute of Standards and Technology, "Digital
+ Signature Standard (DSS)", FIPS PUB 186-2, December 1998.
+
+ [G] Goubin, L., "A Refined Power-Analysis-Attack on Elliptic
+ Curve Cryptosystems", Proceedings of Public-Key-
+ Cryptography - PKC 2003, Lecture Notes in Computer Science
+ 2567, Springer Verlag, 2003.
+
+
+
+Lochter & Merkle Informational [Page 19]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ [CFDA] Cohen, H., Frey, G., Doche, C., Avanzi, R., Lange, T.,
+ Nguyen, K., and F. Vercauteren, "Handbook of Elliptic and
+ Hyperelliptic Curve Cryptography", Chapman & Hall CRC
+ Press, 2006.
+
+ [HMV] Hankerson, D., Menezes, A., and S. Vanstone, "Guide to
+ Elliptic Curve Cryptography", Springer Verlag, 2004.
+
+ [HR] Huang, M. and W. Raskind, "Signature Calculus and the
+ Discrete Logarithm Problem for Elliptic Curves
+ (Preliminary Version)", Unpublished Preprint, 2006,
+ <http://www-rcf.usc.edu/~mdhuang/mypapers/062806dl3.pdf>.
+
+ [ISO1] International Organization for Standardization,
+ "Information Technology - Security Techniques - Digital
+ Signatures with Appendix - Part 3: Discrete Logarithm
+ Based Mechanisms", ISO/IEC 14888-3, 2006.
+
+ [ISO2] International Organization for Standardization,
+ "Information Technology - Security Techniques -
+ Cryptographic Techniques Based on Elliptic Curves - Part
+ 2: Digital signatures", ISO/IEC 15946-2, 2002.
+
+ [ISO3] International Organization for Standardization,
+ "Information Technology - Security Techniques - Prime
+ Number Generation", ISO/IEC 18032, 2005.
+
+ [JMV] Jao, D., Miller, SD., and R. Venkatesan, "Ramanujan Graphs
+ and the Random Reducibility of Discrete Log on Isogenous
+ Elliptic Curves", IACR Cryptology ePrint Archive 2004/312,
+ 2004.
+
+ [RFC3279] Bassham, L., Polk, W., and R. Housley, "Algorithms and
+ Identifiers for the Internet X.509 Public Key
+ Infrastructure Certificate and Certificate Revocation List
+ (CRL) Profile", RFC 3279, April 2002.
+
+ [RFC4050] Blake-Wilson, S., Karlinger, G., Kobayashi, T., and Y.
+ Wang, "Using the Elliptic Curve Signature Algorithm
+ (ECDSA) for XML Digital Signatures", RFC 4050, April 2005.
+
+ [RFC4492] Blake-Wilson, S., Bolyard, N., Gupta, V., Hawk, C., and B.
+ Moeller, "Elliptic Curve Cryptography (ECC) Cipher Suites
+ for Transport Layer Security (TLS)", RFC 4492, May 2006.
+
+ [RFC4754] Fu, D. and J. Solinas, "IKE and IKEv2 Authentication Using
+ the Elliptic Curve Digital Signature Algorithm (ECDSA)",
+ RFC 4754, January 2007.
+
+
+
+Lochter & Merkle Informational [Page 20]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ [RFC5753] Turner, S. and D. Brown, "Use of Elliptic Curve
+ Cryptography (ECC) Algorithms in Cryptographic Message
+ Syntax (CMS)", RFC 5753, January 2010.
+
+ [SA] Satoh, T. and K. Araki, "Fermat Quotients and the
+ Polynomial Time Discrete Log Algorithm for Anomalous
+ Elliptic Curves", Commentarii Mathematici Universitatis
+ Sancti Pauli 47, 1998.
+
+ [SEC1] Certicom Research, "Elliptic Curve Cryptography",
+ Standards for Efficient Cryptography (SEC) 1, September
+ 2000.
+
+ [SEC2] Certicom Research, "Recommended Elliptic Curve Domain
+ Parameters", Standards for Efficient Cryptography (SEC) 2,
+ September 2000.
+
+ [Sem] Semaev, I., "Evaluation of Discrete Logarithms on Some
+ Elliptic Curves", Mathematics of Computation 67, 1998.
+
+ [Sma] Smart, N., "The Discrete Logarithm Problem on Elliptic
+ Curves of Trace One", Journal of Cryptology 12, 1999.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Lochter & Merkle Informational [Page 21]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+Appendix A. Pseudo-Random Generation of Parameters
+
+ In this appendix, the methods used for pseudo-random generation of
+ the elliptic curve domain parameters are described. A comprehensive
+ description is given in [EBP].
+
+ Throughout this section the following conventions are used:
+
+ The conversion between integers x in the range 0 <= x <= 2^L - 1 and
+ bit strings of length L is given by x <--> {x_1,...,x_L} and the
+ binary expansion
+ x = x_1 * 2^(L-1) + x_2 * 2^(L-2) + ... + x_(L-1)*2 + x_L, i.e., the
+ first bit of the bit string corresponds to the most significant bit
+ of the corresponding integer and the last bit to the least
+ significant bit.
+
+ For a real number x, let floor(x) denote the highest integer less
+ than or equal to x.
+
+ For updating the seed s of 160-bit length we use the following
+ function update_seed(s):
+
+ 1. Convert s to an integer z.
+
+ 2. Convert (z+1) mod 2^160 to a bit string t and output t.
+
+A.1. Generation of Prime Numbers
+
+ This section describes the systematic selection of the base fields
+ GF(p) proposed in this specification. The prime generation method is
+ similar to the method given in FIPS 186-2 [FIPS], Appendix 6.4, and
+ ANSI X9.62 [ANSI1], A.3.2. It is a modification of the method
+ "incremental search" given in Section 8.2.2 of [ISO3].
+
+ For computing an integer x in the range 0 <= x <= 2^L - 1 from a seed
+ s of 160-bit length, we use the following algorithm find_integer(s):
+
+ 1. Set v = floor((L-1)/160) and w = L - 160*v.
+
+ 2. Compute h = SHA-1(s).
+
+ 3. Let h_0 be the bit string obtained by taking the w rightmost bits
+ of h.
+
+ 4. Convert s to an integer z.
+
+ 5. For i from 1 to v do:
+
+
+
+
+Lochter & Merkle Informational [Page 22]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ A. Set z_i = (z+i) mod 2^160.
+
+ B. Convert z_i to a bit string s_i.
+
+ C. Set h_i = SHA-1(s_i).
+
+ 6. Let h be the string obtained by the concatenation of h_0,...,h_v
+ from left to right.
+
+ 7. Convert h to an integer x and output x.
+
+ The following procedure is used to generate an L bit prime p from a
+ 160-bit seed s.
+
+ 1. Set c = find_integer(s).
+
+ 2. Let p be the smallest prime p >= c with p = 3 mod 4.
+
+ 3. If 2^(L-1) <= p <= 2^L - 1 output p and stop.
+
+ 4. Set s = update_seed(s) and go to Step 1.
+
+ For the generation of the primes p used as base fields GF(p) for the
+ curves defined in this specification (and the corresponding twisted
+ curves), the following values (in hexadecimal representation) have
+ been used as initial seed s:
+
+ Seed_p_160 for brainpoolP160r1:
+ 3243F6A8885A308D313198A2E03707344A409382
+
+ Seed_p_192 for brainpoolP192r1:
+ 2299F31D0082EFA98EC4E6C89452821E638D0137
+
+ Seed_p_224 for brainpoolP224r1:
+ 7BE5466CF34E90C6CC0AC29B7C97C50DD3F84D5B
+
+ Seed_p_256 for brainpoolP256r1:
+ 5B54709179216D5D98979FB1BD1310BA698DFB5A
+
+ Seed_p_320 for brainpoolP320r1:
+ C2FFD72DBD01ADFB7B8E1AFED6A267E96BA7C904
+
+ Seed_p_384 for brainpoolP384r1:
+ 5F12C7F9924A19947B3916CF70801F2E2858EFC1
+
+ Seed_p_512 for brainpoolP512r1:
+ 6636920D871574E69A458FEA3F4933D7E0D95748
+
+
+
+
+Lochter & Merkle Informational [Page 23]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ These seeds have been obtained as the first 7 substrings of 160-bit
+ length each of Q = Pi*2^1120, where Pi is the constant 3.14159...,
+ also known as Ludolph's number, i.e.,
+
+ Q = Seed_p_160||Seed_p_192||...||Seed_p_512||Remainder,
+ where || denotes concatenation.
+
+ Using these seeds and the above algorithm the following primes are
+ obtained:
+
+ p_160 = 1332297598440044874827085558802491743757193798159
+
+ p_192 = 4781668983906166242955001894344923773259119655253013193367
+
+ p_224 = 2272162293245435278755253799591092807334073214594499230443
+ 5472941311
+
+ p_256 = 7688495639704534422080974662900164909303795020094305520373
+ 5601445031516197751
+
+ p_320 = 1763593322239166354161909842446019520889512772719515192772
+ 9604152886408688021498180955014999035278
+
+ p_384 = 2165927077011931617306923684233260497979611638701764860008
+ 1618503821089934025961822236561982844534088440708417973331
+
+ p_512 = 8948962207650232551656602815159153422162609644098354511344
+ 597187200057010413552439917934304191956942765446530386427345937963
+ 894309923928536070534607816947
+
+A.2. Generation of Pseudo-Random Curves
+
+ The generation procedure is similar to the procedure given in FIPS
+ PUB 186-2 [FIPS], Appendix 6.4, and ANSI X9.62 [ANSI1], A.3.2.
+
+ For computing an integer x in the range 0 <= x <= 2^(L-1) - 1 from a
+ seed s of 160-bit length, we use the algorithm find_integer_2(s),
+ which slightly differs from the method used for the generation of the
+ primes.
+
+ 1. Set v = floor((L-1)/160) and w = L - 160*v - 1.
+
+ 2. Compute h = SHA-1(s).
+
+ 3. Let h_0 be the bit string obtained by taking the w rightmost bits
+ of h.
+
+ 4. Convert s to an integer z.
+
+
+
+Lochter & Merkle Informational [Page 24]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ 5. For i from 1 to v do:
+
+ A. Set z_i = (z+i) mod 2^160.
+
+ B. Convert z_i to a bit string s_i.
+
+ C. Set h_i = SHA-1(s_i).
+
+ 6. Let h be the string obtained by the concatenation of h_0,...,h_v
+ from left to right.
+
+ 7. Convert h to an integer x and output x.
+
+ The following procedure is used to generate the parameters A and B of
+ a suitable elliptic curve over GF(p) and a base point G from a prime
+ p of bit length L and a 160-bit seed s.
+
+ 1. Set h = find_integer_2(s).
+
+ 2. Convert h to an integer A.
+
+ 3. If -3 = A*Z^4 mod p is not solvable, then set s = update_seed(s)
+ and go to Step 1.
+
+ 4. Compute one solution Z of -3 = A*Z^4 mod p.
+
+ 5. Set s = update_seed(s).
+
+ 6. Set B = find_integer_2(s).
+
+ 7. If B is a square mod p, then set s = update_seed(s) and go to
+ Step 6.
+
+ 8. If 4*A^3 + 27*B^2 = 0 mod p, then set s = update_seed(s) and go
+ to Step 1.
+
+ 9. Check that the elliptic curve E over GF(p) given by y^2 = x^3 +
+ A*x + B fulfills all security and functional requirements given
+ in Section 3. If not, then set s = update_seed(s) and go to Step
+ 1.
+
+ 10. Set s = update_seed(s).
+
+ 11. Set k = find_integer_2(s).
+
+ 12. Determine the points Q and -Q having the smallest x-coordinate in
+ E(GF(p)). Randomly select one of them as point P.
+
+
+
+
+Lochter & Merkle Informational [Page 25]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+ 13. Compute the base point G = k * P.
+
+ 14. Output A, B, and G.
+
+ Note: Of course P could also be used as a base point. However, the
+ small x-coordinate of P could possibly render the curve vulnerable to
+ side-channel attacks.
+
+ For the generation of curve parameters A and B, and the base points G
+ defined in this specification, the following values (in hexadecimal
+ representation) have been used as initial seed s:
+
+ Seed_ab_160 for brainpoolP160r1:
+ 2B7E151628AED2A6ABF7158809CF4F3C762E7160
+
+ Seed_ab_192 for brainpoolP192r1:
+ F38B4DA56A784D9045190CFEF324E7738926CFBE
+
+ Seed_ab_224 for brainpoolP224r1:
+ 5F4BF8D8D8C31D763DA06C80ABB1185EB4F7C7B5
+
+ Seed_ab_256 for brainpoolP256r1:
+ 757F5958490CFD47D7C19BB42158D9554F7B46BC
+
+ Seed_ab_320 for brainpoolP320r1:
+ ED55C4D79FD5F24D6613C31C3839A2DDF8A9A276
+
+ Seed_ab_384 for brainpoolP384r1:
+ BCFBFA1C877C56284DAB79CD4C2B3293D20E9E5E
+
+ Seed_ab_512 for brainpoolP384r1:
+ AF02AC60ACC93ED874422A52ECB238FEEE5AB6AD
+
+ These seeds have been obtained as the first 7 substrings of 160-bit
+ length each of R = floor(e*2^1120), where e denotes the constant
+ 2.71828..., also known as Euler's number, i.e.,
+
+ R = Seed_ab_160||Seed_ab_192||...||Seed_ab_512||Remainder,
+ where || denotes concatenation.
+
+
+
+
+
+
+
+
+
+
+
+
+Lochter & Merkle Informational [Page 26]
+
+RFC 5639 ECC Brainpool Standard Curves & Curve Generation March 2010
+
+
+Authors' Addresses
+
+ Manfred Lochter
+ Bundesamt fuer Sicherheit in der Informationstechnik (BSI)
+ Postfach 200363
+ 53133 Bonn
+ Germany
+
+ Phone: +49 228 9582 5643
+ EMail: manfred.lochter@bsi.bund.de
+
+
+ Johannes Merkle
+ secunet Security Networks
+ Mergenthaler Allee 77
+ 65760 Eschborn
+ Germany
+
+ Phone: +49 201 5454 2021
+ EMail: johannes.merkle@secunet.com
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
+Lochter & Merkle Informational [Page 27]
+