Class: Ltec::EC

Inherits:
Object
  • Object
show all
Defined in:
lib/ltec.rb

Overview

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Constant Summary collapse

SECP256K1 = 
'secp256k1'

Class Method Summary collapse

Class Method Details

.base64(str) ⇒ Object 



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# File 'lib/ltec.rb', line 12

def EC.base64(str)
    return Base64.strict_encode64(str)
end

.base64Decode(str) ⇒ Object 



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# File 'lib/ltec.rb', line 15

def EC.base64Decode(str)
    return Base64.decode64(str)
end

.base64ToHex(base64) ⇒ Object 



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# File 'lib/ltec.rb', line 27

def EC.base64ToHex(base64)
    return base64.unpack("m*")[0].unpack('H*')[0]
end

.decrypt(secKey, base64Cipher) ⇒ Object 



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# File 'lib/ltec.rb', line 117

def EC.decrypt(secKey,base64Cipher)
    encResult = base64Decode(base64Cipher)
    start = 8
    nonce = encResult[start...(start + 16)] 
    start = start + 16;
    mac = encResult[start...(start + 32)]
    start = start + 32;
    tmpPub = encResult[start...(start + 33)]
    start = start + 33;
    dataEnc = encResult[start...(encResult.length)]

    tmpPubHex = toHex(tmpPub)
    ec = OpenSSL::PKey::EC.new(SECP256K1)
    tmpBn = OpenSSL::BN.new(tmpPubHex,16)

    tmpPt = OpenSSL::PKey::EC::Point.new(ec.group,tmpBn)

    priKey = OpenSSL::BN.new(toHex(base64Decode(secKey)),16) 
    ptDh = tmpPt.mul(priKey);

    ptX = fromHex(ptDh.to_bn(:compressed).to_s(16))[1...33]
    dhHash = OpenSSL::Digest.digest("SHA512", ptX)

    key = dhHash[0...32]
    hmakkey = dhHash[32...64]

    # check mac 
    dataforMac = nonce + tmpPub + dataEnc
    mac2 = OpenSSL::HMAC.digest('sha256', hmakkey, dataforMac)
    if mac2 != mac 
        raise 'Mac not Fit,the privateKey is not fit'
    end
    # encryptor = Salsa20.new(key, nonce)
    # txt = encryptor.decrypt(dataEnc)
    encryptor = OpenSSL::Cipher::AES256.new(:CBC)
    encryptor.decrypt
    encryptor.key =  key
    encryptor.iv =  nonce
    txt = encryptor.update(dataEnc) + encryptor.final
    return txt
end

.encrypt(pubKey, msg) ⇒ Object 



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# File 'lib/ltec.rb', line 70

def EC.encrypt(pubKey,msg)
    hex = base64ToHex(pubKey)
    ec = OpenSSL::PKey::EC.new(SECP256K1)
    # puts ec 
    # puts ec.group
    pubNum = OpenSSL::BN.new(hex,16)
    pt = OpenSSL::PKey::EC::Point.new(ec.group,pubNum)

    randKey = OpenSSL::Random.random_bytes(32)
    hexRnd = toHex(randKey)
    rndBn = OpenSSL::BN.new(hexRnd,16)

    # 0 < rndBn < OrderOfG
    if rndBn.zero? 
        raise "OpenSSL::Random.random_bytes generate Fail"
    end


    rndPt =  pt.mul(0,rndBn)
    hexpt = rndPt.to_bn(:compressed).to_s(16)

    empherPub = fromHex(hexpt)
        
    #ecdh 
    ptDh = pt.mul(rndBn)
    ptX = fromHex(ptDh.to_bn(:compressed).to_s(16))[1...33]
        
    dhHash = OpenSSL::Digest.digest("SHA512", ptX)
        
    nonce = OpenSSL::Random.random_bytes(16)

    encryptor = OpenSSL::Cipher::AES256.new(:CBC)
    encryptor.encrypt
    encryptor.key =  dhHash[0...32]
    encryptor.iv =  nonce
    

    # encryptor = Salsa20.new(dhHash[0...32], nonce)
    encrypted_text = encryptor.update(msg) + encryptor.final
    dataforMac = nonce + empherPub + encrypted_text
    mac = OpenSSL::HMAC.digest('sha256', dhHash[32,64], dataforMac)

    # 
    return base64(fromHex('0100100020002100') + nonce + mac + empherPub + encrypted_text)
        
end

.fromHex(hex) ⇒ Object 



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# File 'lib/ltec.rb', line 21

def EC.fromHex(hex)
    return [hex].pack("H*")
end

.generateKeyPair(inputSecKey) ⇒ Object 



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# File 'lib/ltec.rb', line 31

def EC.generateKeyPair(inputSecKey)
    if inputSecKey 
        puts "generate key pair from secret key"
       if inputSecKey.length < 44   # 32 byte
           throw "secret key length error ,it's 32 "
           
       end

        ec = OpenSSL::PKey::EC.new(SECP256K1)
        pubNum = OpenSSL::BN.new("1",16)
        tmpPt = OpenSSL::PKey::EC::Point.new(ec.group)

        priKey = OpenSSL::BN.new(toHex(base64Decode(inputSecKey)),16) 

        maxStr = 'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141'
        OpenSSL
        max = OpenSSL::BN.new(maxStr,16) 
        if priKey >= max
            throw "Private Key must be smaller than #{maxStr}"
        end




        pubPt =  tmpPt.mul(0,priKey)
        hexpt = pubPt.to_bn(:compressed).to_s(16)
        pub64 = hexToBase64(hexpt)

        return {"seckey" => inputSecKey.strip,"pubkey" => pub64.strip}
    else 
        puts 'create New key pair'
        ec1 = OpenSSL::PKey::EC.generate(SECP256K1)
        seckey = EC.hexToBase64(ec1.private_key.to_s(16))
        pubkey = EC.hexToBase64(ec1.public_key.to_bn(:compressed).to_s(16))
        return {"seckey" => seckey.strip,"pubkey" => pubkey.strip}
    end
   
end

.hexToBase64(hex) ⇒ Object 



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# File 'lib/ltec.rb', line 24

def EC.hexToBase64(hex)
    return [[hex].pack("H*")].pack("m") 
end

.test ⇒ Object 



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# File 'lib/ltec.rb', line 159

def EC.test()
   puts 'hello R'
end

.toHex(str) ⇒ Object 



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# File 'lib/ltec.rb', line 18

def EC.toHex(str)
    return str.unpack('H*')[0]
end

.xDec(priKey, msg) ⇒ Object 



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# File 'lib/ltec.rb', line 164

def EC.xDec(priKey,msg)
    priHex = base64ToHex(priKey)
    prN = OpenSSL::BN.new(priHex,16)
    bfMsg = base64Decode(msg)
    pub = bfMsg[0,33]
    pubhex = toHex(pub)
    

    
    pubNum = OpenSSL::BN.new(pubhex,16)
    curve = OpenSSL::PKey::EC::Group.new(SECP256K1)
    ptPub = OpenSSL::PKey::EC::Point.new(curve,pubNum)

    ptDh = ptPub.mul(prN)
    ptX = fromHex(ptDh.to_bn(:compressed).to_s(16))[1...33]

    dhHash = OpenSSL::Digest.digest("SHA512", ptX)
    encryptor = OpenSSL::Cipher::AES256.new(:CTR)
    encryptor.decrypt
    encryptor.key =  dhHash[0...32]
    encryptor.iv =  dhHash[32...48]

    
    EC.base64(encryptor.update(bfMsg[33..-1]) + encryptor.final)
end

.xEnc(pubKey, msg64) ⇒ Object 



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# File 'lib/ltec.rb', line 189

def EC.xEnc(pubKey,msg64)
    msg = base64Decode(msg64)
    hex = base64ToHex(pubKey)


    ec = OpenSSL::PKey::EC.new(SECP256K1)
    curve = OpenSSL::PKey::EC::Group.new(SECP256K1)
    kp = OpenSSL::PKey::EC::generate(curve)
    pubNum = OpenSSL::BN.new(hex,16)
    ptPub = OpenSSL::PKey::EC::Point.new(ec.group,pubNum)

    rndBn = kp.private_key.to_bn
    ptTmp = kp.public_key

    ptDh =  ptPub.mul(rndBn)
    ptX = fromHex(ptDh.to_bn(:compressed).to_s(16))[1...33]

    dhHash = OpenSSL::Digest.digest("SHA512", ptX)
    encryptor = OpenSSL::Cipher::AES256.new(:CTR)
    encryptor.encrypt
    encryptor.key =  dhHash[0...32]
    encryptor.iv =  dhHash[32...48]
    EC.base64( fromHex(ptTmp.to_bn(:compressed).to_s(16)) + encryptor.update(msg) + encryptor.final)
end