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author | Ulf Möller <ulf@openssl.org> | 2000-02-05 10:41:05 +0000 |
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committer | Ulf Möller <ulf@openssl.org> | 2000-02-05 10:41:05 +0000 |
commit | c236e66d628ec4a7d24612dd5c94c35c6b170af8 (patch) | |
tree | 3633b455af6ade2c3ed35fcc510e4e7bdc2e8ee0 /doc/crypto | |
parent | 981b87f7120ee38afb797c48edf4a6f16ef28053 (diff) |
Document RC4.
Diffstat (limited to 'doc/crypto')
-rw-r--r-- | doc/crypto/rc4.pod | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/doc/crypto/rc4.pod b/doc/crypto/rc4.pod new file mode 100644 index 0000000000..e380045dbf --- /dev/null +++ b/doc/crypto/rc4.pod @@ -0,0 +1,58 @@ +=pod + +=head1 NAME + +RC4_set_key, RC4 - RC4 encryption + +=head1 SYNOPSIS + + #include <openssl/rc4.h> + + void RC4_set_key(RC4_KEY *key, int len, const unsigned char *data); + + void RC4(RC4_KEY *key, unsigned long len, const unsigned char *indata, + unsigned char *outdata); + +=head1 DESCRIPTION + +This library implements the Alleged RC4 cipher, which is described for +example in I<Applied Cryptography>. It is believed to be compatible +with RC4[TM], a proprietary cipher of RSA Security Inc. + +RC4 is a stream cipher with variable key length. Typically, 128 bit +(16 byte) keys are used for strong encryption, but shorter insecure +key sizes have been widely used due to export restrictions. + +RC4 consists of a key setup phase and the actual encryption or +decryption phase. + +RC4_set_key() sets up the B<RC4_KEY> B<key> using the B<len> bytes long +key at B<data>. + +RC4() encrypts or decrypts the B<len> bytes of data at B<indata> using +B<key> and places the result at B<outdata>. Repeated RC4() calls with +the same B<key> yield a continuous key stream. + +Since RC4 is a stream cipher (the input is XORed with a pseudo-random +key stream to produce the output), decryption uses the same function +calls as encryption. + +=head1 RETURN VALUES + +RC4_set_key() and RC4() do not return values. + +=head1 NOTE + +Certain conditions have to be observed to securely use stream ciphers. +It is not permissible to perform multiple encryptions using the same +key stream. + +=head1 SEE ALSO + +L<blowfish(3)|blowfish(3)>, L<des(3)|des(3)>, L<rc2(3)|rc2(3)> + +=head1 HISTORY + +RC4_set_key() and RC4() are available in all versions of SSLeay and OpenSSL. + +=cut |