ref: 75c92428225428c8fde2d015f010e608a0b12f1d
dir: purgatorio/man/2/keyring-rc4
.TH KEYRING-RC4 2 .SH NAME keyring: rc4setup, rc4, rc4skip, rc4back \- RC4 encryption .SH SYNOPSIS .EX 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); .EE .SH 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. .PP .B Rc4setup sets the initial .IR 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. .PP .B Rc4 runs the generator starting with the given .IR state , and XORs the output of the generator with the first .I n bytes of .IR buf , updating the .IR state . .B Rc4 is symmetric and is used both to encrypt and decrypt. .B Rc4skip skips over bytes (eg, to account for lost transmissions); .B rc4back runs the generator backwards (eg, to account for retransmissions). .SH SEE ALSO .IR keyring-intro (2), .IR keyring-crypt (2)