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-rw-r--r-- | WARNING.RNG | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/WARNING.RNG b/WARNING.RNG index 5f129f40..21f4901c 100644 --- a/WARNING.RNG +++ b/WARNING.RNG @@ -12,16 +12,14 @@ A particularly pernicious problem arises with DSA keys (used by the ssh2 protocol). Performing a DSA signature (which is required for authentication), entails the use of a 160 bit random number. If an attacker can predict this number, then they can deduce your *private* -key and impersonate you. +key and impersonate you or your hosts. If you are using the builtin random number support (configure will -tell you if this is the case), then read this document in its entirety -and consider disabling ssh2 support (by adding "Protocol 1" to -sshd_config and ssh_config). +tell you if this is the case), then read this document in its entirety. Please also request that your OS vendor provides a kernel-based random number collector (/dev/random) in future versions of your operating -systems. +systems by default. On to the description... @@ -40,9 +38,10 @@ the specified program. The random number code will also read and save a seed file to ~/.ssh/prng_seed. This contents of this file are added to the random -number generator at startup. +number generator at startup. The goal here is to maintain as much +randomness between sessions as possible. -This approach presents two problems: +The entropy collection code has two main problems: 1. It is slow. |