man.postnix Miscellaneous man pages of Plan 9 related material

     KEYRING-RC4(2)                                     KEYRING-RC4(2)

     NAME
          keyring: rc4setup, rc4, rc4skip, rc4back - RC4 encryption

     SYNOPSIS
          include "keyring.m";
          keyring := load Keyring Keyring->PATH;

          rc4setup: fn(seed: array of byte): ref RC4state;
          rc4:      fn(state: ref RC4state, buf: array of byte, n: int);
          rc4skip:  fn(state: ref RC4state, n: int);
          rc4back:  fn(state: ref RC4state, n: int);

     DESCRIPTION
          These functions implement the stream encryption algorithm
          that is claimed to be equivalent to RSA Security's RC4.  It
          is a pseudo-random number generator with a 256 byte state
          and a long cycle.

          Rc4setup sets the initial seed, which can be any non-zero
          length, and returns a representation of the initial state of
          the algorithm, which is used in subsequent calls.

          Rc4 runs the generator starting with the given state, and
          XORs the output of the generator with the first n bytes of
          buf, updating the state. Rc4 is symmetric and is used both
          to encrypt and decrypt.  Rc4skip skips over bytes (eg, to
          account for lost transmissions); rc4back runs the generator
          backwards (eg, to account for retransmissions).

     SEE ALSO
          keyring-intro(2), keyring-crypt(2)

     Page 1                       Plan 9            (printed 10/30/25)