| CPC H04L 63/0861 (2013.01) [H04L 43/04 (2013.01); H04L 63/083 (2013.01); H04L 63/0876 (2013.01); H04L 63/105 (2013.01); H04L 63/1433 (2013.01); H04L 63/1408 (2013.01); H04L 2463/082 (2013.01)] | 30 Claims | 

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               1. A computer system configured to execute software instructions stored on nontransitory machine-readable storage media, wherein the software instructions comprise instructions that: 
            receive a request to authenticate a client, wherein the request comprises a first identifier and a password, 
                store, in a multidimensional time-series database, information about the request, 
                determine whether the password corresponds to a first user account identified by the first identifier, 
                determine whether an additional verification is required to grant access, 
                wherein determining whether the additional verification is required to grant access comprises: 
                retrieving, from the multidimensional time-series database, historical information about previous access requests associated with the first user account, and 
                    determining, based at least on the historical information, whether the first user account is associated with a previous request to authenticate, wherein the previous request to authenticate comprised a second identifier not associated with the first user account; and, 
                  based on the additional verification being required to grant access: 
              select an additional verification method from a plurality of verification methods, 
                  cause the client to be prompted to complete the additional verification method, and 
                  determine whether the additional verification method has been completed correctly. 
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