From 78e51a8c6678b6e3dff3d619aa786669f531f4bc Mon Sep 17 00:00:00 2001 From: rsc Date: Fri, 14 Jan 2005 03:45:44 +0000 Subject: checkpoint --- man/man3/des.html | 170 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 170 insertions(+) create mode 100644 man/man3/des.html (limited to 'man/man3/des.html') diff --git a/man/man3/des.html b/man/man3/des.html new file mode 100644 index 00000000..0752e8c8 --- /dev/null +++ b/man/man3/des.html @@ -0,0 +1,170 @@ + +des(3) - Plan 9 from User Space + + + + +
+
+
DES(3)DES(3) +
+
+

NAME
+ +
+ + setupDESstate, des_key_setup, block_cipher, desCBCencrypt, desCBCdecrypt, + desECBencrypt, desECBdecrypt, des3CBCencrypt, des3CBCdecrypt, + des3ECBencrypt, des3ECBdecrypt, key_setup, des56to64, des64to56, + setupDES3state, triple_block_cipher, - single and triple digital + encryption standard + +
+

SYNOPSIS
+ +
+ + #include <u.h>
+ #include <libc.h>
+ #include <mp.h>
+ #include <libsec.h> +
+ + void des_key_setup(uchar key[8], ulong schedule[32]) +
+ + void block_cipher(ulong *schedule, uchar *data,            int decrypting) + +
+ + void setupDESstate(DESstate *s, uchar key[8], uchar *ivec) +
+ + void desCBCencrypt(uchar*, int, DESstate*) +
+ + void desCBCdecrypt(uchar*, int, DESstate*) +
+ + void desECBencrypt(uchar*, int, DESstate*) +
+ + void desECBdecrypt(uchar*, int, DESstate*) +
+ + void triple_block_cipher(ulong keys[3][32], uchar*, int) +
+ + void setupDES3state(DES3state *s, uchar key[3][8],                  uchar *ivec) + +
+ + void des3CBCencrypt(uchar*, int, DES3state*) +
+ + void des3CBCdecrypt(uchar*, int, DES3state*) +
+ + void des3ECBencrypt(uchar*, int, DES3state*) +
+ + void des3ECBdecrypt(uchar*, int, DES3state*) +
+ + void key_setup(uchar[7], ulong[32]) +
+ + void des56to64(uchar *k56, uchar *k64) +
+ + void des64to56(uchar *k64, uchar *k56)
+ +
+

DESCRIPTION
+ +
+ + +
+ + The Digital Encryption Standard (DES) is a shared key or symmetric + encryption using either a 56 bit key for single DES or three 56 + bit keys for triple des. The keys are encoded into 64 bits where + every eight bit is parity. +
+ + The basic DES function, block_cipher, works on a block of 8 bytes, + converting them in place. It takes a key schedule, a pointer to + the block, and a flag indicating encrypting (0) or decrypting + (1). The key schedule is created from the key using des_key_setup. + +
+ + Since it is a bit awkward, block_cipher is rarely called directly. + Instead, one normally uses routines that encrypt larger buffers + of data and which may chain the encryption state from one buffer + to the next. These routines keep track of the state of the encryption + using a DESstate structure that contains the key + schedule and any chained state. SetupDESstate sets up the DESstate + structure using the key and an 8 byte initialization vector. +
+ + Electronic code book, using desECBencrypt and desECBdecrypt, is + the less secure mode. The encryption of each 8 bytes does not + depend on the encryption of any other. Hence the encryption is + a substitution cipher using 64 bit characters. +
+ + Cipher block chaining mode, using desCBCencrypt and desCBCdecrypt, + is more secure. Every block encrypted depends on the initialization + vector and all blocks encrypted before it. +
+ + For both CBC and ECB modes, a stream of data can be encrypted + as multiple buffers. However, all buffers except the last must + be a multiple of 8 bytes to ensure successful decryption of the + stream. +
+ + There are equivalent triple DES functions for each of the DES + functions. +
+ + In the past Plan 9 used a 56 bit or 7 byte format for DES keys. + To be compatible with the rest of the world, we’ve abandoned this + format. There are two functions: des56to64 and des64to56 to convert + back and forth between the two formats. Also a key schedule can + be set up from the 7 byte format using key_setup. +
+ + +
+

SOURCE
+ +
+ + /usr/local/plan9/src/libsec
+ +
+

SEE ALSO
+ +
+ + mp(3), aes(3), blowfish(3), dsa(3), elgamal(3), rc4(3), rsa(3), + sechash(3), prime(3), rand(3)
+ +
+ +

 +
+
+ + +
+
+
+Space Glenda +
+
+ + -- cgit v1.2.3