[PR #7] HMAC based One Time Password #34

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opened 2026-02-25 22:30:50 +03:00 by kerem · 0 comments

kerem commented

2026-02-25 22:30:50 +03:00

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Original Pull Request: https://github.com/evgeny-gridasov/openvpn-otp/pull/7

State: closed
Merged: Yes

This pull request implements support for HMAC based One Time Password (hotp)

HOTP tokens needs to store the value of the current counter somewhere, in order to keep in sync with the client. As stated in the README; for each HOTP entry in the otp-secrets files, we compute the sha1 checksum of the secret key, and we use the result as the filename.

The diff is huge because this pull request is built on top of #6. Together, these two features allows an administrator to create backups codes for users, by precomputing them and using a small counter value.

**Original Pull Request:** https://github.com/evgeny-gridasov/openvpn-otp/pull/7 **State:** closed **Merged:** Yes --- This pull request implements support for [HMAC based One Time Password (hotp)](https://tools.ietf.org/html/rfc4226) HOTP tokens needs to store the value of the current counter somewhere, in order to keep in sync with the client. As stated in the README; for each HOTP entry in the `otp-secrets` files, we compute the sha1 checksum of the secret key, and we use the result as the filename. The diff is huge because this pull request is built on top of #6. Together, these two features allows an administrator to create backups codes for users, by precomputing them and using a small counter value.