a528d4f0a9
If something was "present in all versions" of SSLeay, or if it was added to a version of SSLeay (and therefore predates OpenSSL), remove mention of it. Documentation history now starts with OpenSSL. Remove mention of all history before OpenSSL 0.9.8, inclusive. Remove all AUTHOR sections. Reviewed-by: Tim Hudson <tjh@openssl.org>
57 lines
1.6 KiB
Text
57 lines
1.6 KiB
Text
=pod
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=head1 NAME
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RC4_set_key, RC4 - RC4 encryption
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=head1 SYNOPSIS
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#include <openssl/rc4.h>
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void RC4_set_key(RC4_KEY *key, int len, const unsigned char *data);
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void RC4(RC4_KEY *key, unsigned long len, const unsigned char *indata,
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unsigned char *outdata);
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=head1 DESCRIPTION
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This library implements the Alleged RC4 cipher, which is described for
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example in I<Applied Cryptography>. It is believed to be compatible
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with RC4[TM], a proprietary cipher of RSA Security Inc.
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RC4 is a stream cipher with variable key length. Typically, 128 bit
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(16 byte) keys are used for strong encryption, but shorter insecure
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key sizes have been widely used due to export restrictions.
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RC4 consists of a key setup phase and the actual encryption or
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decryption phase.
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RC4_set_key() sets up the B<RC4_KEY> B<key> using the B<len> bytes long
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key at B<data>.
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RC4() encrypts or decrypts the B<len> bytes of data at B<indata> using
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B<key> and places the result at B<outdata>. Repeated RC4() calls with
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the same B<key> yield a continuous key stream.
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Since RC4 is a stream cipher (the input is XORed with a pseudo-random
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key stream to produce the output), decryption uses the same function
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calls as encryption.
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=head1 RETURN VALUES
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RC4_set_key() and RC4() do not return values.
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=head1 NOTE
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Applications should use the higher level functions
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L<EVP_EncryptInit(3)> etc. instead of calling these
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functions directly.
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It is difficult to securely use stream ciphers. For example, do not perform
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multiple encryptions using the same key stream.
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=head1 SEE ALSO
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L<EVP_EncryptInit(3)>
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=cut
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