3f: Scrambling

    ++un

    Reversible scrambling

    A core that contains arms that perform reversible scrambling operations. Used in the @p phonetic base.

    Source

        ++  un
          |%
    

    ++wren:un

    Conceal structure

    Scrambles a byte-string pyn by adding the current position to each byte, looking it up in an s-box, and then performing the XOR operation on the result, pushing it forward. The inverse of wred.

    Accepts

    pyn is an atom.

    Produces

    An atom.

    Source

          ++  wren
            |=  pyn=@  ^-  @
            =+  len=(met 3 pyn)
            ?:  =(0 len)
              0
            =>  .(len (dec len))
            =+  mig=(zaft (xafo len (cut 3 [len 1] pyn)))
            %+  can  3
            %-  flop  ^-  (list [@ @])
            :-  [1 mig]
            |-  ^-  (list [@ @])
            ?:  =(0 len)
              ~
            =>  .(len (dec len))
            =+  mog=(zyft :(mix mig (end 3 1 len) (cut 3 [len 1] pyn)))
            [[1 mog] $(mig mog)]
          ::
    

    Examples

        > `@ux`(wren:un 'testing')
        0x30.bf6a.b9fe.7d8f
    
        > `@ux`'testing'
        0x67.6e69.7473.6574
    
        > `@da`(wred:un (wren:un ~2001.2.5))
        ~2001.2.5
    

    ++wred:un

    Restore structure

    Unscrambles a byte-string cry by subtracting the current position from each byte, looking it up in an s-box, and performing the XOR operation on the result, pushing it forward. The inverse of wren.

    Accepts

    cry is an atom.

    Produces

    An atom.

    Source

          ++  wred
            |=  cry=@  ^-  @
            =+  len=(met 3 cry)
            ?:  =(0 len)
              0
            =>  .(len (dec len))
            =+  mig=(cut 3 [len 1] cry)
            %+  can  3
            %-  flop  ^-  (list [@ @])
            :-  [1 (xaro len (zart mig))]
            |-  ^-  (list [@ @])
            ?:  =(0 len)
              ~
            =>  .(len (dec len))
            =+  mog=(cut 3 [len 1] cry)
            [[1 :(mix mig (end 3 1 len) (zyrt mog))] $(mig mog)]
          ::
    

    Examples

        > (wred:un 0x30.bf6a.b9fe.7d8f)
        29.113.321.805.538.676
    
        > `@t`(wred:un 0x30.bf6a.b9fe.7d8f)
        'testing'
    
        > (wred:un (wren:un 200.038.426))
        200.038.426
    

    ++xafo:un

    Add modulo 255

    Produces the sum of two atoms modulo 255, encoded as a nonzero byte. The inverse of xaro.

    Accepts

    a is an atom.

    b is an atom.

    Produces

    An atom.

    Source

          ++  xafo  |=([a=@ b=@] +((mod (add (dec b) a) 255)))
    

    Examples

        > (xafo:un 5 6)
        11
    
        > (xafo:un 256 20)
        21
    
        > (xafo:un 256 (xaro:un 256 20))
        20
    

    ++xaro:un

    Subtract modulo 255

    Produces the sum of two atoms modulo 255, encoded as a nonzero byte. The inverse of xafo.

    Accepts

    a is an atom.

    b is an atom.

    Produces

    An atom.

    Source

          ++  xaro  |=([a=@ b=@] +((mod (add (dec b) (sub 255 (mod a 255))) 255)))
    

    Examples

        > (xaro:un 17 57)
        40
    
        > (xaro:un 265 12)
        2
    
        > (xaro:un 256 (xafo:un 256 20))
        20
    

    ++zaft:un

    Look up in 255 sub box

    Looks up a nonzero byte a in a substitution box with 255 values, producing a unique nonzero byte. The inverse of zart.

    Accepts

    a is an atom of one byte in length.

    Produces

    An atom.

    Source

          ++  zaft
            |=  a=@D
            =+  ^=  b
                0xcc.75bc.86c8.2fb1.9a42.f0b3.79a0.92ca.21f6.1e41.cde5.fcc0.
                7e85.51ae.1005.c72d.1246.07e8.7c64.a914.8d69.d9f4.59c2.8038.
                1f4a.dca2.6fdf.66f9.f561.a12e.5a16.f7b0.a39f.364e.cb70.7318.
                1de1.ad31.63d1.abd4.db68.6a33.134d.a760.edee.5434.493a.e323.
                930d.8f3d.3562.bb81.0b24.43cf.bea5.a6eb.52b4.0229.06b2.6704.
                78c9.45ec.d75e.58af.c577.b7b9.c40e.017d.90c3.87f8.96fa.1153.
                0372.7f30.1c32.ac83.ff17.c6e4.d36d.6b55.e2ce.8c71.8a5b.b6f3.
                9d4b.eab5.8b3c.e7f2.a8fe.9574.5de0.bf20.3f15.9784.9939.5f9c.
                e609.564f.d8a4.b825.9819.94aa.2c08.8e4c.9b22.477a.2840.3ed6.
                3750.6ef1.44dd.89ef.6576.d00a.fbda.9ed2.3b6c.7b0c.bde9.2ade.
                5c88.c182.481a.1b0f.2bfd.d591.2726.57ba
            (cut 3 [(dec a) 1] b)
    

    Examples

        > (zaft:un 0x12)
        42
    
        > (zaft:un 0xff)
        204
        > `@ux`(zart:un 204)
        0xff
    
        > (zaft:un 0x0)
        ! decrement-underflow
        ! exit
    

    ++zart:un

    Reverse look up in 255 sub box

    Looks up the index of a nonzero byte a in the substitution box with 255 values, producing a unique nonzero byte. The inverse of zaft.

    Accepts

    a is an atom of one byte in length.

    Produces

    An atom.

    Source

          ++  zart                                              ::  reverse 255-sbox
            |=  a=@D
            =+  ^=  b
                0x68.4f07.ea1c.73c9.75c2.efc8.d559.5125.f621.a7a8.8591.5613.
                dd52.40eb.65a2.60b7.4bcb.1123.ceb0.1bd6.3c84.2906.b164.19b3.
                1e95.5fec.ffbc.f187.fbe2.6680.7c77.d30e.e94a.9414.fd9a.017d.
                3a7e.5a55.8ff5.8bf9.c181.e5b6.6ab2.35da.50aa.9293.3bc0.cdc6.
                f3bf.1a58.4130.f844.3846.744e.36a0.f205.789e.32d8.5e54.5c22.
                0f76.fce7.4569.0d99.d26e.e879.dc16.2df4.887f.1ffe.4dba.6f5d.
                bbcc.2663.1762.aed7.af8a.ca20.dbb4.9bc7.a942.834c.105b.c4d4.
                8202.3e61.a671.90e6.273d.bdab.3157.cfa4.0c2e.df86.2496.f7ed.
                2b48.2a9d.5318.a343.d128.be9c.a5ad.6bb5.6dfa.c5e1.3408.128d.
                2c04.0339.97a1.2ff0.49d0.eeb8.6c0a.0b37.b967.c347.d9ac.e072.
                e409.7b9f.1598.1d3f.33de.8ce3.8970.8e7a
            (cut 3 [(dec a) 1] b)
          ::
    

    Examples

        > `@ux`(zart:un 204)
        0xff
    
        > `@ux`(zart:un 42)
        0x12
    
        > (zaft:un 0x12)
        42
    

    ++zyft:un

    Lookup byte in 256 sub box

    Looks up a byte a in a substitution box with 256 values, producing a byte. The inverse of zyrt.

    Accepts

    a is an atom of one byte in length.

    Produces

    An atom.

    Source

          ++  zyft                                              ::  forward 256-sbox
            |=  a=@D
            =+  ^=  b
                0xbb49.b71f.b881.b402.17e4.6b86.69b5.1647.115f.dddb.7ca5.
                  8371.4bd5.19a9.b092.605d.0d9b.e030.a0cc.78ba.5706.4d2d.
                  986a.768c.f8e8.c4c7.2f1c.effe.3cae.01c0.253e.65d3.3872.
                  ce0e.7a74.8ac6.daac.7e5c.6479.44ec.4143.3d20.4af0.ee6c.
                  c828.deca.0377.249f.ffcd.7b4f.eb7d.66f2.8951.042e.595a.
                  8e13.f9c3.a79a.f788.6199.9391.7fab.6200.4ce5.0758.e2f1.
                  7594.c945.d218.4248.afa1.e61a.54fb.1482.bea4.96a2.3473.
                  63c2.e7cb.155b.120a.4ed7.bfd8.b31b.4008.f329.fca3.5380.
                  9556.0cb2.8722.2bea.e96e.3ac5.d1bc.10e3.2c52.a62a.b1d6.
                  35aa.d05e.f6a8.0f3b.31ed.559d.09ad.f585.6d21.fd1d.8d67.
                  370b.26f4.70c1.b923.4684.6fbd.cf8b.5036.0539.9cdc.d93f.
                  9068.1edf.8f33.b632.d427.97fa.9ee1
            (cut 3 [a 1] b)
          ::
    

    Examples

        > (zyft:un 0x12)
        57
    
        > (zyft:un 0x0)
        225
    
        > (zyft:un 0xff)
        187
        > `@ux`(zyrt:un 187)
        0xff
    

    ++zyrt:un

    Reverse lookup byte in 256 sub box

    Looks up a byte a in a substitution box with 256 values, producing a byte. The inverse of zyft.

    Accepts

    a is an atom of one byte in length.

    Produces

    An atom.

    Source

          ++  zyrt                                              ::  reverse 256-sbox
            |=  a=@D
            =+  ^=  b
                0x9fc8.2753.6e02.8fcf.8b35.2b20.5598.7caa.c9a9.30b0.9b48.
                  47ce.6371.80f6.407d.00dd.0aa5.ed10.ecb7.0f5a.5c3a.e605.
                  c077.4337.17bd.9eda.62a4.79a7.ccb8.44cd.8e64.1ec4.5b6b.
                  1842.ffd8.1dfb.fd07.f2f9.594c.3be3.73c6.2cb6.8438.e434.
                  8d3d.ea6a.5268.72db.a001.2e11.de8c.88d3.0369.4f7a.87e2.
                  860d.0991.25d0.16b9.978a.4bf4.2a1a.e96c.fa50.85b5.9aeb.
                  9dbb.b2d9.a2d1.7bba.66be.e81f.1946.29a8.f5d2.f30c.2499.
                  c1b3.6583.89e1.ee36.e0b4.6092.937e.d74e.2f6f.513e.9615.
                  9c5d.d581.e7ab.fe74.f01b.78b1.ae75.af57.0ec2.adc7.3245.
                  12bf.2314.3967.0806.31dc.cb94.d43f.493c.54a6.0421.c3a1.
                  1c4a.28ac.fc0b.26ca.5870.e576.f7f1.616d.905f.ef41.33bc.
                  df4d.225e.2d56.7fd6.1395.a3f8.c582
            (cut 3 [a 1] b)
    

    Examples

        > `@ux`(zyrt:un 57)
        0x12
    
        > `@ux`(zyrt:un 225)
        0x0
    
        > `@ux`(zyrt:un 187)
        0xff
        > (zyft:un 0xff)
        187
    

    ++ob

    Reversible scrambling, v2

        ++  ob
          |%
    

    A core for performing reversible scrambling operations for the @p phonetic base.


    ++feen:ob

    Conceal structure, v2

    Randomly permutes atoms that fit into 17 to 32 bits into one another. If the atom fits into 33 to 64 bits, does the same permutation on the low 32 bits only. Otherwise, passes the atom through unchanged.

    Accepts

    An atom.

    Produces

    An atom.

    Source

          ++  feen
            |=  pyn=@  ^-  @
            ?:  &((gte pyn 0x1.0000) (lte pyn 0xffff.ffff))
              (add 0x1.0000 (fice (sub pyn 0x1.0000)))
            ?:  &((gte pyn 0x1.0000.0000) (lte pyn 0xffff.ffff.ffff.ffff))
              =+  lo=(dis pyn 0xffff.ffff)
              =+  hi=(dis pyn 0xffff.ffff.0000.0000)
              %+  con  hi
              (add 0x1.0000 (fice (sub lo 0x1.0000)))
            pyn
          ::
    

    Examples

        > `@p`(feen:ob 111.103)
        ~mophul-pagwyx
    
        > `@p`(feen:ob ~mophul-pagwyx)
        ~wisfed-lonwes
    
        > `@p`(feen:ob (fend:ob ~mophul-pagwyx))
        ~mophul-pagwyx
    
        > `@p`(feen:ob ~wex)
        ~wex
    

    ++fend:ob

    Restore structure, v2

    Randomly permutes atoms that fit into 17 to 32 bits into one another, and randomly permutes the low 32 bits of atoms that fit into 33 to 64 bits; otherwise, passes the atom through unchanged. The inverse of the one applied by feen.

    Accepts

    An atom.

    Produces

    An atom.

    Source

          ++  fend
            |=  cry=@  ^-  @
            ?:  &((gte cry 0x1.0000) (lte cry 0xffff.ffff))
              (add 0x1.0000 (teil (sub cry 0x1.0000)))
            ?:  &((gte cry 0x1.0000.0000) (lte cry 0xffff.ffff.ffff.ffff))
              =+  lo=(dis cry 0xffff.ffff)
              =+  hi=(dis cry 0xffff.ffff.0000.0000)
              %+  con  hi
              (add 0x1.0000 (teil (sub lo 0x1.0000)))
            cry
          ::
    

    Examples

        > `@p`(fend:ob 111.103)
        ~doznec-sapfes
    
        > `@p`(fend:ob ~doznec-sapfes)
        ~hanrud-widwyc
    
        > `@p`(fend:ob ~wisfed-lonwes)
        ~mophul-pagwyx
    
        > `@p`(fend:ob (feen:ob ~wisfed-lonwes))
        ~wisfed-lonwes
    
        > `@p`(fend:ob ~tarmed)
        ~tarmed
    

    ++fice:ob

    Feistel-like cipher

    Produces an atom by applying a variant of the Feistel cipher. Unlike a conventional Feistel cipher that is its own inverse if keys are used in reverse order, this Feistel-like cipher uses two moduli that must be swapped when applying the reverse transformation. The inverse of teil.

    Accepts

    nor is an atom.

    Produces

    An atom.

    Source

              ++  fice                                              ::  adapted from
                |=  nor=@                                           ::  black and rogaway
                ^-  @                                               ::  "ciphers with
                =+  ^=  sel                                         ::   arbitrary finite
                %+  rynd  2                                         ::   domains", 2002
                %+  rynd  1
                %+  rynd  0
                [(mod nor 65.535) (div nor 65.535)]
                (add (mul 65.535 -.sel) +.sel)
              ::
    

    Examples

        > (fice:ob 11)
        776.343.932
    
        > (fice:ob (teil:ob 11))
        11
    

    ++teil:ob

    Reverse Feistel-like cipher

    Applies the reverse of the Feistel-like cipher applied by fice. Unlike a conventional Feistel cipher that is its own inverse if keys are used in reverse order, this Feistel-like cipher uses two moduli that must be swapped when applying the reverse transformation.

    Accepts

    vip is an atom.

    Produces

    An atom.

    Source

          ++  teil                                              ::  reverse ++fice
            |=  vip=@
            ^-  @
            =+  ^=  sel
            %+  rund  0
            %+  rund  1
            %+  rund  2
            [(mod vip 65.535) (div vip 65.535)]
            (add (mul 65.535 -.sel) +.sel)
          ::
    

    Examples

        > (teil:ob 11)
        514.230.493
    
        > (teil:ob (fice:ob 11))
        11
    

    ++rynd:ob

    Reverse Feistel-like cipher

    A single round of the Feistel-like cipher fice. AES (aesc) is used as the round function. The inverse of rund.

    Accepts

    n is an atom.

    l is an atom.

    r is an atom.

    Produces

    A cell of two atoms.

    Source

        ++  rynd
          |=  [n=@ l=@ r=@]
          ^-  [@ @]
          :-  r
          ?~  (mod n 2)
            (~(sum fo 65.535) l (en:aesc (snag n raku) r))
          (~(sum fo 65.536) l (en:aesc (snag n raku) r))
    

    Examples

        > (rynd:ob 2 261 9)
        [9 37.422]
    
        > (rynd:ob 2 (rund:ob 2 37.422 9))
        [261 32.902]
    

    ++rund:ob

    Reverse single Feistel-like

    A single round of the Feistel-like reverse cipher teil. AES (aesc) is used as the round function. The inverse of rynd.

    Accepts

    n is an atom.

    l is an atom.

    r is an atom.

    Produces

    A cell of two atoms.

    Source

      ++  rund
        |=  [n=@ l=@ r=@]
        ^-  [@ @]
        :-  r
        ?~  (mod n 2)
          (~(dif fo 65.535) l (muk (snag n raku) 2 r))
        (~(dif fo 65.536) l (muk (snag n raku) 2 r))
    

    Examples

        > (rund:ob 2 261 9)
        [9 28.635]
    
        > (rund:ob 2 (rynd:ob 2 28.635 9))
        [261 32.651]
    

    ++raku:ob

    Key list

    Produces a list of arbitrary hexademical keys for use with aesc.

    Produces

    A list of atoms of aura @ux (hexadecimal).

    Source

      ++  raku
        ^-  (list @ux)
        :~  0xb76d.5eed
            0xee28.1300
            0x85bc.ae01
            0x4b38.7af7
        ==
        --
    

    Examples

        > raku:ob
        ~[0xb76d.5eed 0xee28.1300 0x85bc.ae01 0x4b38.7af7]