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[openssl.git] / doc / crypto / rand.pod

diff --git a/doc/crypto/rand.pod b/doc/crypto/rand.pod
index 588b082e7c67a2482e4c211f5eed845c83f7d1eb..5104b070a1ade2870414cb7c63fab732f4eaa586 100644 (file)
--- a/doc/crypto/rand.pod
+++ b/doc/crypto/rand.pod
@@ -2,7 +2,7 @@
 
 =head1 NAME
 
-rand - Psdeudo-random number generator
+rand - Pseudo-random number generator
 
 =head1 SYNOPSIS
 
@@ -13,11 +13,14 @@ rand - Psdeudo-random number generator
 
  void RAND_seed(const void *buf,int num);
  void RAND_add(const void *buf,int num,int entropy);
+ int  RAND_status(void);
  void RAND_screen(void);
 
  int  RAND_load_file(const char *file,long max_bytes);
  int  RAND_write_file(const char *file);
- char *RAND_file_name(char *file,int num);
+ const char *RAND_file_name(char *file,int num);
+
+ int  RAND_egd(const char *path);
 
  void RAND_set_rand_method(RAND_METHOD *meth);
  RAND_METHOD *RAND_get_rand_method(void);
@@ -34,11 +37,12 @@ need randomness.
 
 A cryptographic PRNG must be seeded with unpredictable data such as
 mouse movements or keys pressed at random by the user. This is
-described in L<RAND_add(3)>. Its state can be saved in a seed file
-(see L<RAND_load_file(3)>) to avoid having to go through the seeding
-process whenever the application is started.
+described in L<RAND_add(3)|RAND_add(3)>. Its state can be saved in a seed file
+(see L<RAND_load_file(3)|RAND_load_file(3)>) to avoid having to go through the
+seeding process whenever the application is started.
 
-L<RAND_bytes(3)> describes how to obtain random data from the PRNG.
+L<RAND_bytes(3)|RAND_bytes(3)> describes how to obtain random data from the
+PRNG. 
 
 =head1 INTERNALS
 
@@ -101,12 +105,12 @@ the RNG state or the next random number.
 The algorithm is as follows.
 
 There is global state made up of a 1023 byte buffer (the 'state'), a
-working hash function ('md') and a counter ('count').
+working hash value ('md'), and a counter ('count').
 
 Whenever seed data is added, it is inserted into the 'state' as
 follows.
 
-The input is chopped up into units of 16 bytes (or less for
+The input is chopped up into units of 20 bytes (or less for
 the last block).  Each of these blocks is run through the hash
 function as follows:  The data passed to the hash function
 is the current 'md', the same number of bytes from the 'state'
@@ -121,28 +125,34 @@ SHA-1), 3 (the 'state'), 4 (via the 'md'), 5 (by the use of a hash
 function and xor).
 
 When bytes are extracted from the RNG, the following process is used.
-For each group of 8 bytes (or less), we do the following,
-
-Input into the hash function, the top 8 bytes from 'md', the byte that
-are to be overwritten by the random bytes and bytes from the 'state'
-(incrementing looping index).  From this hash function output (which
-is kept in 'md'), the top (upto) 8 bytes are returned to the caller
-and the bottom (upto) 8 bytes are xored into the 'state'.
-
-Finally, after we have finished 'generation' random bytes for the
-called, 'count' (which is incremented) and 'md' are fed into the hash
-function and the results are kept in 'md'.  I believe the above
-addressed points 1 (use of SHA-1), 6 (by hashing into the 'state' the
-'old' data from the caller that is about to be overwritten) and 7 (by
-not using the 8 bytes given to the caller to update the 'state', but
-they are used to update 'md').
+For each group of 10 bytes (or less), we do the following:
+
+Input into the hash function the top 10 bytes from the local 'md'
+(which is initialized from the global 'md' before any bytes are
+generated), the bytes that are to be overwritten by the random bytes,
+and bytes from the 'state' (incrementing looping index). From this
+digest output (which is kept in 'md'), the top (up to) 10 bytes are
+returned to the caller and the bottom (up to) 10 bytes are xored into
+the 'state'.
+
+Finally, after we have finished 'num' random bytes for the caller,
+'count' (which is incremented) and the local and global 'md' are fed
+into the hash function and the results are kept in the global 'md'.
+
+I believe the above addressed points 1 (use of SHA-1), 6 (by hashing
+into the 'state' the 'old' data from the caller that is about to be
+overwritten) and 7 (by not using the 10 bytes given to the caller to
+update the 'state', but they are used to update 'md').
 
 So of the points raised, only 2 is not addressed (but see
-L<RAND_add()>).
+L<RAND_add(3)|RAND_add(3)>).
 
 =head1 SEE ALSO
 
-BN_rand(3), RAND_add(3), RAND_load_file(3), RAND_bytes(3),
-RAND_set_rand_method(3), RAND_cleanup(3)
+L<BN_rand(3)|BN_rand(3)>, L<RAND_add(3)|RAND_add(3)>,
+L<RAND_load_file(3)|RAND_load_file(3)>, L<RAND_egd(3)|RAND_egd(3)>,
+L<RAND_bytes(3)|RAND_bytes(3)>,
+L<RAND_set_rand_method(3)|RAND_set_rand_method(3)>,
+L<RAND_cleanup(3)|RAND_cleanup(3)> 
 
 =cut