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AEB, Improved descrtiption of read from /dev/urandom

This commit is contained in:
Michael Kerrisk 2005-04-08 07:58:55 +00:00
parent 055fd5fae5
commit c892f4ca9f
1 changed files with 4 additions and 2 deletions
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6
man4/random.4
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@ -8,6 +8,7 @@
.\" Some changes by tytso and aeb.
.\"
.\" 2004-12-16, John V. Belmonte/mtk, Updated init and quit scripts
.\" 2004-04-08, AEB, Improved descrtiption of read from /dev/urandom
.\"
.TH RANDOM 4 2003-10-25 "Linux" "Linux Programmer's Manual"
.SH NAME
@ -33,8 +34,9 @@ high quality randomness such as one-time pad or key generation.
When the entropy pool is empty, reads from \fB/dev/random\fP will block
until additional environmental noise is gathered.
.LP
When read, \fB/dev/urandom\fP device will return as many bytes as are
requested. As a result, if there is not sufficient entropy in the
A read from the \fB/dev/urandom\fP device will not block
waiting for more entropy.
As a result, if there is not sufficient entropy in the
entropy pool, the returned values are theoretically vulnerable to a
cryptographic attack on the algorithms used by the driver. Knowledge of
how to do this is not available in the current non-classified