The OATH Toolkit makes it easy to build one-time password authentication systems. It contains shared libraries, commandline tools, and a PAM module. Supported technologies include the event-based HOTP algorithm (RFC4226) and the time-based TOTP algorithm (RFC6238). OATH stands for Open AuTHentication, which is the organization which specifies the algorithms. For managing secret key files, the Portable Symmetric Key Container (PSKC) format described in RFC6030 is supported.
dynalogin is a distributed two-factor authentication suite that combines a secure UNIX server and API with an Android soft token. Open standards (HOTP, TOTP, and soon OCRA) are used for one-time passwords. A C library is provided for inclusion in existing software and Web sites. OpenID (using SimpleID) is supported for Web applications and single sign on. PAM is supported for easy UNIX and LDAP integration (SASL, RADIUS, and JAAS in development). It works with Google Authenticator or the dynalogin Android application.