OpenVPN Auth Digest Algorithm list contains entries that are functionally identical and thus redundant
The way "openvpn --show-digests" works it ends up listing several algorithms that are functionally equivalent but some of the duplicate options do not work on other clients, which can be confusing for users.
For example, both RSA-SHA256 and SHA256 are in the list, but in this context openvpn only uses the SHA256 portion. Some clients can't use "RSA-SHA256" but can instead use "SHA256" and it works for both ends.
#1 Updated by Jim Pingle about 2 years ago
This also appears to be confirmed by
openssl list-message-digest-algorithms, which lists which names/aliases map to underlying digests.
DSA DSA-SHA DSA-SHA1 => DSA DSA-SHA1-old => DSA-SHA1 DSS1 => DSA-SHA1 MD4 MD5 MDC2 RIPEMD160 RSA-MD4 => MD4 RSA-MD5 => MD5 RSA-MDC2 => MDC2 RSA-RIPEMD160 => RIPEMD160 RSA-SHA => SHA RSA-SHA1 => SHA1 RSA-SHA1-2 => RSA-SHA1 RSA-SHA224 => SHA224 RSA-SHA256 => SHA256 RSA-SHA384 => SHA384 RSA-SHA512 => SHA512 SHA SHA1 SHA224 SHA256 SHA384 SHA512 DSA DSA-SHA dsaWithSHA1 => DSA dss1 => DSA-SHA1 ecdsa-with-SHA1 MD4 md4WithRSAEncryption => MD4 MD5 md5WithRSAEncryption => MD5 MDC2 mdc2WithRSA => MDC2 ripemd => RIPEMD160 RIPEMD160 ripemd160WithRSA => RIPEMD160 rmd160 => RIPEMD160 SHA SHA1 sha1WithRSAEncryption => SHA1 SHA224 sha224WithRSAEncryption => SHA224 SHA256 sha256WithRSAEncryption => SHA256 SHA384 sha384WithRSAEncryption => SHA384 SHA512 sha512WithRSAEncryption => SHA512 shaWithRSAEncryption => SHA ssl2-md5 => MD5 ssl3-md5 => MD5 ssl3-sha1 => SHA1 whirlpool
#2 Updated by Jim Pingle about 2 years ago
- Status changed from Assigned to Feedback
I pushed a fix for this in f49ef559060ec8cad5c7a3a548d509cf08b5549b but forgot to put this ticket number on the commit so it would automatically set to feedback.
It should be all OK now, and existing settings that used the aliased names will be corrected to the actual underlying names on upgrade.
If someone has issues with exporting or other functional problems because of the value on 2.3.x or other versions, simply edit the server or client and choose the correct digest algorithm (e.g. the one without RSA- or other prefixes in front, in most cases).