Sha256: 090c4eda5a8cca856d8db596d08cfb7d8a02cd5c4ded3156685a6db084defc09
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Size: 1.85 KB
Versions: 20
Compression:
Stored size: 1.85 KB
Contents
class Epics::Key
attr_accessor :key
def initialize(encoded_key, passphrase = nil)
if encoded_key.kind_of?(OpenSSL::PKey::RSA)
self.key = encoded_key
else
self.key = OpenSSL::PKey::RSA.new(encoded_key)
end
end
###
# concat the exponent and modulus (hex representation) with a single whitespace
# remove leading zeros from both
# calculate digest (SHA256)
# encode as Base64
####
def public_digest
c = [ e.gsub(/^0*/,''), n.gsub(/^0*/,'') ].map(&:downcase).join(" ")
Base64.encode64(digester.digest(c)).strip
end
def n
self.key.n.to_s(16)
end
def e
self.key.e.to_s(16)
end
def sign(msg, salt = OpenSSL::Random.random_bytes(32) )
Base64.encode64(mod_pow(OpenSSL::BN.new(emsa_pss(msg, salt).to_s, 2), self.key.d, self.key.n).to_s(2)).gsub("\n", "")
end
def recover(msg)
mod_pow(OpenSSL::BN.new(msg.to_s, 2), self.key.e, self.key.n).to_s(2)
end
def digester
@digester ||= OpenSSL::Digest::SHA256.new
end
private
##
# http://de.wikipedia.org/wiki/Probabilistic_Signature_Scheme
##
def emsa_pss(msg, salt)
m_tick_hash = digester.digest [("\x00" * 8), digester.digest(msg), salt].join
ps = "\x00" * 190
db = [ps, "\x01", salt].join
db_mask = Epics::MGF1.new.generate(m_tick_hash, db.size)
masked_db = Epics::MGF1.new.xor(db, db_mask)
masked_db_msb = OpenSSL::BN.new(masked_db[0], 2).to_i.to_s(2).rjust(8, "0")
masked_db_msb[0] = "0"
masked_db[0] = OpenSSL::BN.new(masked_db_msb.to_i(2).to_s).to_s(2)
[masked_db, m_tick_hash, ["BC"].pack("H*") ].join
end
def mod_pow(base, power, mod)
base = base.to_i
power = power.to_i
mod = mod.to_i
result = 1
while power > 0
result = (result * base) % mod if power & 1 == 1
base = (base * base) % mod
power >>= 1
end
OpenSSL::BN.new(result.to_s)
end
end
Version data entries
20 entries across 20 versions & 1 rubygems