41 lines
1.4 KiB
Factor
41 lines
1.4 KiB
Factor
! Copyright (C) 2009 Doug Coleman.
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! See http://factorcode.org/license.txt for BSD license.
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USING: combinators.short-circuit help.markup help.syntax kernel
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math math.functions math.primes random ;
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IN: math.primes.safe
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HELP: next-safe-prime
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{ $values
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{ "n" integer }
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{ "q" integer }
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}
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{ $description "Tests consecutive numbers and returns the next safe prime. A safe prime is desirable in cryptography applications such as Diffie-Hellman and SRP6." } ;
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HELP: random-safe-prime
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{ $values
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{ "numbits" integer }
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{ "p" integer }
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}
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{ $description "Returns a safe prime number " { $snippet "numbits" } " bits in length, with the topmost bit set to one." } ;
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HELP: safe-prime?
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{ $values
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{ "q" integer }
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{ "?" "a boolean" }
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}
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{ $description "Tests whether the number is a safe prime. A safe prime " { $snippet "p" } " must be prime, as must " { $snippet "(p - 1) / 2" } "." } ;
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ARTICLE: "math.primes.safe" "Safe prime numbers"
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"The " { $vocab-link "math.primes.safe" } " vocabulary implements words to calculate safe prime numbers. Safe primes are of the form " { $snippet "p = 2q + 1" } ", where " { $snippet "p" } ", " { $snippet "q" } " are prime. Safe primes have desirable qualities for cryptographic applications." $nl
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"Testing if a number is a safe prime:"
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{ $subsections safe-prime? }
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"Generating safe prime numbers:"
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{ $subsections
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next-safe-prime
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random-safe-prime
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} ;
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ABOUT: "math.primes.safe"
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