Analysis of Smart Card-Based Remote User Authentication Schemes

There are prepared 7-azabenzimidazoles of the formula where R1 and R2 are the same or different and are hydrogen, C1-C6-alkyl or C2-C6-alkanol or -NR1R2 is a 5 to 7 membered saturated heterocyclic ring having either one nitrogen atom, one nitrogen atom and one oxygen atom or two nitrogen atoms, R3 is hydroxy, an amino group, a mono C1-C6-Alkylamino group, a di-C1-C6-alkylamino group, or a C2-C6-alkylamino, di-C1-C6-alkylamino, mercapto, C1-C6-alkylmercapto, hydroxy or C1-C6-alkoxy, R5 is hydrogen or halogen and A is a C2-C6-alkylene group or a salt of such compound. Preferably R1 and R2 are two equal C1-C6-alkyl groups or -NR1R2 is piperidino, pyrrolidino, morpholino, homopiperidino, piperazino or homopiperazino, R3 is hydroxy, mercapto, C1-C4-alkoxy, C1-C4-alkylmercapto or C1-C6-alkylmino, mercapto, C1-C6-alkylmercapto, hydroxy or C1-C6-alkoxy and R5 is hydrogen and salts thereof. The compounds are useful in treating ulcers and gastritis.