Abstract: The present invention provides a novel configuration which allows devices capable of processing different signature algorithms to mutually verify public key certificates. In this configuration, public key certificates storing plural signatures based on different signature algorithms such as RSA and ECC are issued and each device selects a signature which can be processed (namely, verified) by itself and verifies the selected signature.

Abstract: A public key certificate issuing system is disclosed which comprises a certificate authority for issuing a public key certificate used by an entity, and a registration authority which, on receiving a public key certificate issuance request from any one of entities under jurisdiction thereof, transmits the received request to the certificate authority. The certificate authority, having a plurality of signature modules each executing a different signature algorithm, selects at least one of the plurality of signature modules in accordance with the public key certificate issuance request from the registration authority, and causes the selected signature module to attach a digital signature to message data constituting a public key certificate.

Abstract: In a content delivery system, delivery of a content and charging for the fee of the content are performed and managed in a highly secure and effective fashion. If a content-purchasing request is transmitted from a user device to a shop server, a charging process is performed. If the charging process is successfully completed, the shop server transmits, to the user device, an encrypted content key in a form which can be decrypted by a key stored in the user device. A user device authentication server, which manages content delivery, converts an encrypted content key KpDAS(Kc) encrypted using a public key of the user device authentication server (DAS) into an encrypted content key KpDEV(Kc) encrypted using a public key KpDEV of the user device. Provided that the charging process has been successfully completed in response to the content-purchasing request, the shop server transmits the key-converted content key to the user device.

Abstract: 2-Aryl-8-oxodihydropurine derivative of the following formula (I): wherein W is H, lower alkyl, halogen, lower alkoxy, amino, mono- or di-lower alkylamino, or substituted or unsubstituted phenyl; X is H, lower alkyl, cycloalkyl-lower alkyl, substituted or unsubstituted phenyl-lower alkyl, lower alkenyl, carbamoyl, di-lower alkylcarbamoyl, or a group of the formula (Q): —CH(R3)CON(R1)(R2); Y is H, lower alkyl, cycloalkyl, cycloalkyl-lower alkyl, lower alkenyl, substituted or unsubstituted phenyl-lower alkyl, or a group of the formula (Q): —CH(R3)CON(R1)(R2); A is substituted or unsubstituted phenyl, or substituted or unsubstituted heteroaryl; provided that when one of X and Y of the above formula (I) is the group of the formula (Q), then the other is the same groups for X or Y as described above except for the group of the formula (Q), or a pharmaceutically acceptable acid addition salt thereof.

Abstract: A 5-substituted-3-oxadiazolyl-1,6-naphthyridin-2(1H)-one derivative of the formula (I): wherein Het is oxadiazolyl, R1 is H, lower alkyl, cyclo-lower alkyl, trifluoromethyl, lower alkenyl, lower alkynyl, lower alkoxy, lower alkoxy-lower alkyl, hydroxy-lower alkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaromatic group, and R2 is H, lower alkyl, cyclo-lower alkyl, cyclo-lower alkylmethyl, lower alkenyl, cyclo-lower alkenyl, lower alkynyl, substituted or unsubstituted aryl, or substituted or unsubstituted hetero-aromatic group, or a pharmaceutically acceptable acid addition salt thereof, which has high selective affinity to benzodiazepine receptor and is useful particularly as a benzodiazepine inverse agonist, for example, as psychoanaleptic drug or a drug for the treatment of dysmnesia in senile dementia or Alzheimer's disease.

Abstract: A 5-substituted-3-oxadiazolyl-1,6-naphthyridin-2(1H)-one derivative of the formula (I): wherein Het is oxadiazolyl, R1 is H, lower alkyl, cyclo-lower alkyl, trifluoromethyl, lower alkenyl, lower alkynyl, lower alkoxy, lower alkoxy-lower alkyl, hydroxy-lower alkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaromatic group, and R2 is H, lower alkyl, cyclo-lower alkyl, cyclo-lower alkylmethyl, lower alkenyl, cyclo-lower alkenyl, lower alkynyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaromatic group, or a pharmaceutically acceptable acid addition salt thereof, which has high selective affinity to benzodiazepine receptor and is useful particularly as a benzodiazepine inverse agonist, for example, as psychoanaleptic drug or a drug for the treatment of dysmnesia in senile dementia or Alzheimer's disease.

Abstract: An acetamide derivative of the formula (I): ##STR1## wherein X is --0-- or --NR.sub.4 --, R.sub.1 is H, lower alkyl, lower alkenyl or cyclolalkyl-lower-alkyl, R.sub.2 is lower alkyl, cycloalkyl, substituted or unsubstituted phenyl, etc., R.sub.3 is H, lower alkyl or hydroxy-lower alkyl, R.sub.4 is H, lower alkyl, etc., R.sub.5 is H, lower alkyl, lower alkenyl, hydroxy-lower alkyl, etc., R.sub.6 is H, lower alkyl, CF.sub.3, substituted or unsubstituted phenyl, or R.sub.5 and R.sub.6 may optionally combine to form --(CH.sub.2)n--, R.sub.7 is H, halogen, lower alkyl, lower alkoxy, CF.sub.3, OH, NH.sub.2, etc., R.sub.8 is H, halogen, lower alkyl or lower alkoxy, or a pharmaceutically acceptable acid addition salt thereof. The compounds of the present invention selectively act on the peripheral-type BZ.omega..sub.

Abstract: 3-Oxadiazolyl-5,6,7,8-tetrahydro-1,6-naphthyridine derivative of the formula (I): ##STR1## wherein Het is an oxadiazole ring, R.sub.1 is hydrogen atom, an acyl group, a lower alkyl group or a group of the formula: --CH.sub.2 R.sub.1 ' (in which R.sub.1 ' is a cyclo-lower alkyl group, a lower alkenyl group, a lower alkynyl group, benzyl group, aryl group or a heteroaromatic group), R.sub.2 is a lower alkyl group, a cyclo-lower alkyl group, a lower alkenyl group, a lower alkynyl group, aryl group, a heteroaromatic group, a halogeno-lower alkyl group, a lower alkoxy-lower alkyl group, a lower alkoxy group, a lower alkenyloxy group, a phenoxy group or a lower alkylthio group, or a pharmaceutically acceptable acid addition salt thereof, which are useful as benzodiazepine receptor agonist.

Abstract: 3-Oxadiazolyl-5,6,7,8-tetrahydro-1,6-naphthyridine derivative of the formula (I): ##STR1## wherein Het is an oxadiazole ring, R.sub.1 is hydrogen atom, an acyl group, a lower alkyl group or a group of the formula: --CH.sub.2 R.sub.1' (in which R.sub.1' is a cyclo-lower alkyl group, a lower alkenyl group, a lower alkynyl group, benzyl group, aryl group or a heteroaromatic group), R.sub.2 is a lower alkyl group, a cyclo-lower alkyl group, a lower alkenyl group, a lower alkynyl group, aryl group, a heteroaromatic group, a halogeno-lower alkyl group, a lower alkoxy-lower alkyl group, a lower alkoxy group, a lower alkenyloxy group, a phenoxy group or a lower alkylthio group, or a pharmaceutically acceptable acid addition salt thereof, which are useful as benzodiazepine receptor agonist.

Abstract: 3-Oxadiazolyl-5,6,7,8-tetrahydro-1,6-naphthyridine derivative of the formula (I): ##STR1## wherein Het is an oxadiazole ring, R.sub.1 is hydrogen atom, an acyl group, a lower alkyl group or a group of the formula: --CH.sub.2 R.sub.1 ' (in which R.sub.1 ' is a cyclo-lower alkyl group, a lower alkenyl group, a lower alkynyl group, benzyl group, aryl group or a heteroaromatic groups), R.sub.2 is a lower alkyl group, a cyclo-lower alkyl group, a lower alkenyl group, a lower alkynyl group, aryl group, a heteroaromatic group, a halogeno-lower alkyl group, a lower alkoxy-lower alkyl group, a lower alkoxy group, a lower alkenyloxy group, a phenoxy group, or a lower alkylthio group, or a pharmaceutically acceptable acid addition salt thereof, which are useful as benzodiazedine receptor agonist.

Abstract: Medicament for the treatment of cerebral insufficiency diseases comprising as an active ingredient a compound of the formula: ##STR1## wherein n is 3, 4, 5 or 6; R.sup.1 is hydrogen atom, C.sub.1 -C.sub.6 alkyl, C.sub.3 -C.sub.8 cycloalkyl, hydroxy-C.sub.2 -C.sub.6) alkyl, unsubstituted or substituted aryl, heteroaryl, unsubstituted or substituted aryl-(C.sub.1 -C.sub.6) alkyl, unsubstituted or substituted aryl-carbonyl-(C.sub.1 -C.sub.6) alkyl, or acyl; R.sup.2 is hydrogen atom, halogen atom, C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkoxy, or trifluoromethyl; and R.sup.3 is hydrogen atom or C.sub.1 -C.sub.6 alkyl, or an acid addition salt thereof, novel 2-(1-piperazinyl)-4-phenyl-cycloalkanopyrimidine derivatives having excellent cerebral function improving activity, processes for the preparation thereof.

Abstract: Medicament for the treatment of cerebral insufficiency diseases comprising as an active ingredient a compound of the formula: ##STR1## wherein n is 3, 4, 5 or 6; R.sup.1 is hydrogen atom, C.sub.1 -C.sub.6 alkyl, C.sub.3 -C.sub.8 cycloalkyl, hydroxy-(C.sub.2 -C.sub.6) alkyl, unsubstituted or substituted aryl, heteroaryl, unsubstituted or substituted aryl-(C.sub.1 -C.sub.6) alkyl, unsubstituted or substituted arylcarbonyl-(C.sub.1 -C.sub.6) alkyl, or acyl; R.sup.2 is hydrogen atom, halogen atom, C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkoxy, or trifluoromethyl; and R.sup.3 is hydrogen atom or C.sub.1 -C.sub.6 alkyl, or an acid addition salt thereof, novel 2-(1-piperazinyl)-4-phenyl-cycloalkanopyrimidine derivatives having excellent cerebral function improving activity, processes for the preparation thereof.

Abstract: Novel 2-(1-piperazinyl)-4-phenyl-cycloalkanopyridine derivatives of the formula (I): ##STR1## wherein n is 3, 4, 5, 6 or 7; R.sup.1 is a hydrogen atom, C.sub.1 -C.sub.10 alkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, C.sub.3 -C.sub.8 cycloalkyl, C.sub.3 -C.sub.6 cycloalkyl-(C.sub.1 -C.sub.4) alkyl, hydroxy-(C.sub.2 -C.sub.6) alkyl, C.sub.1 -C.sub.3 alkoxy-(C.sub.2 -C.sub.6) alkyl, acyloxy-(C.sub.2 -C.sub.6), alkyl, unsubstituted or substituted aroyl-(C.sub.1 -C.sub.6) alkyl, unsubstituted or substituted aryl, heteroaryl, or acyl; R.sup.2 and R.sup.3 are the same or different and are each a hydrogen atom, a halogen atom, C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkoxy, trifluoromethyl, or hydroxy; R.sup.4, R.sup.5 and R.sup.6 are the same or different and are each a hydrogen atom, C.sub.1 -C.sub.6 alkyl, or phenyl, or two of R.sup.4, R.sup.5 and R.sup.6 combine to form a single bond or C.sub.1 -C.sub.3 alkylene; R.sup.7 and R.sup.8 are the same or different and are each a hydrogen atom or C.sub.