Difference between revisions of "Talk:EVP Signing and Verifying"
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Why is | Why is | ||
if(1 != EVP_DigestSignFinal(mdctx, *sig, slen)) goto err; | if(1 != EVP_DigestSignFinal(mdctx, *sig, slen)) goto err; | ||
| − | done two times? | + | done two times?--[[User:Doru001|Doru001]] 13:04, 16 June 2013 (UTC) |
---- | ---- | ||
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--[[User:Matt|Matt]] 21:16, 15 June 2013 (UTC) | --[[User:Matt|Matt]] 21:16, 15 June 2013 (UTC) | ||
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| + | ---- | ||
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| + | Thank you, now it is clear. [[User:Doru001|Doru001]] 13:04, 16 June 2013 (UTC) | ||
Latest revision as of 13:04, 16 June 2013
Clarification required[edit]
Why is
if(1 != EVP_DigestSignFinal(mdctx, *sig, slen)) goto err;
done two times?--Doru001 13:04, 16 June 2013 (UTC)
Good question! I've added some extra code comments to explain it. Basically the first call has a NULL sig parameter to obtain the length of the signature. Memory is then allocated sufficient to hold the sig, and then the sig is obtained in the second call to EVP_DigestSignFinal.
--Matt 21:16, 15 June 2013 (UTC)
Thank you, now it is clear. Doru001 13:04, 16 June 2013 (UTC)
