A secure magnetic stripe card stripe reader (MSR) module and software system capable of encrypting the magnetic stripe data to CPI, SDP and CISP standards for use in point of sale (POS) and other applications requiring data security using non secure networks and computing devices. Additionally, when incorporated within an attachment for conventional personal digital assistant (PDA) or cell phone or stationary terminal, provides encrypted data from the magnetic head assembly providing compliance with Federal Information Processing Standards Publication Series FIPS 140 covering security and tampering standards. Moreover, this module and software system includes the capability of providing secure POS transactions to legacy transaction processing systems and POS terminals transparently to the existing infrastructure. Furthermore, this module and software system includes the capability of transparently providing detection of fraudulently copied magnetic stripe cards.