Can merchants use encryption solutions not listed on the PCI Council's website to reduce their PCI DSS validation effort?
Yes, however, PCI SSC recommends the use of PCI-listed P2PE solutions. Reference to What effect does the use of a PCI-listed P2PE solution have on a merchant's PCI DSS validation? Merchants using encryption solutions that are not included on PCI SSC's list of Validated P2PE Solutions should consult with their acquirer or the payment brands about the use of these solutions. See How do I contact the payment card brands? for information regarding contacting the payment brands.