And we have an answer from the provider-

Before a round starts we form a stack of cards, this is Result, then we generate random Secret and calculate Hash from Result+Secret, which is shown to the player before he places a bet.  From the player we receive his bet and Client Seed, check Result and in the end we have Final Result.
To check the round we offer Verify Service. The player sends Result+Secret and Seed and receives  Hash + Final Result.

'secret={"deck":"AD:8D:KS:TS:4H:2D:8H:TS:TS:JD:4C:7S:AC:3S:6D:QD:JD:QS:JS:QS:3D:2D:2D:8D:TS:3S:7D:JS:TS:6D:JH:AH:6H:8D:6C:8H:5S:4H:8C:6H:9C:4D:7H:QC:JS:AS:2H:6S:AS:4S:4H:7H:2S:6S:3H:2C:JC:4C:QD:9C:QC:JC:JH:8S:TD:JS:2H:9S:5C:7D:3D:3C:AC:JD:QC:KS:2S:5D:2S:4D:2C:6S:3C:AS:6S:TS:3S:4D:KD:5H:JC:QD:8H:9H:7S:KD:5C:5D:TC:5H:TD:7C:KH:9H:3D:QC:JD:8D:KS:9C:7S:KC:KC:TD:7S:KC:KD:2D:AH:3H:6D:3H:7D:2C:7C:TH:AD:KD:5C:KC:3S:JS:7S:8S:TC:JH:4H:AC:KD:5H:3D:KS:5H:AC:2S:3D:7H:4S:3C:QC:6D:8C:6S:QH:7C:TH:JH:9S:4C:4D:AD:QS:9C:3C:QS:7D:TC:8C:TD:5H:AD:AH:4S:4D:QH:5C:9D:9S:9H:8C:2S:4H:5H:8H:TD:KD:9D:2D:AS:AD:7C:4C:6C:KS:8C:5S:5C:3D:5S:9H:TD:2H:JS:4D:8D:QH:TH:JC:AS:KH:JD:7D:3S:JH:6H:5D:6H:QH:7H:9S:6C:8S:7H:9D:AH:2H:QD:QC:KH:3S:KH:6H:2H:AH:AC:2D:6H:2C:5C:9D:4S:2S:9D:4C:QS:8S:9C:7H:JH:KC:4S:8H:6D:TH:8H:3H:3H:QD:KS:7D:TC:6D:8C:TC:QH:3C:6C:TH:6C:AC:QH:9H:5D:4C:2C:2C:4H:7C:JC:7C:6C:8S:9C:5S:5S:JD:8S:2H:9D:KH:6S:TC:TH:KH:AD:5S:5D:QD:AH:4S:5D:QS:AS:3C:9S:9S:JC:3H:7S:KC:9H:8D","game":"MultihandBlackjack","secret":"e0cddc60ac48a3b940be78c9e73ceea3"}&client_seed=86'

{"hash":"b229956571f88ac0acf4410cffd23a36dd5e34986d63d9827215131a0fb64571","result":"3S:4D:KD:5H:JC:QD:8H:9H:7S:KD:5C:5D:TC:5H:TD:7C:KH:9H:3D:QC:JD:8D:KS:9C:7S:KC:KC:TD:7S:KC:KD:2D:AH:3H:6D:3H:7D:2C:7C:TH:AD:KD:5C:KC:3S:JS:7S:8S:TC:JH:4H:AC:KD:5H:3D:KS:5H:AC:2S:3D:7H:4S:3C:QC:6D:8C:6S:QH:7C:TH:JH:9S:4C:4D:AD:QS:9C:3C:QS:7D:TC:8C:TD:5H:AD:AH:4S:4D:QH:5C:9D:9S:9H:8C:2S:4H:5H:8H:TD:KD:9D:2D:AS:AD:7C:4C:6C:KS:8C:5S:5C:3D:5S:9H:TD:2H:JS:4D:8D:QH:TH:JC:AS:KH:JD:7D:3S:JH:6H:5D:6H:QH:7H:9S:6C:8S:7H:9D:AH:2H:QD:QC:KH:3S:KH:6H:2H:AH:AC:2D:6H:2C:5C:9D:4S:2S:9D:4C:QS:8S:9C:7H:JH:KC:4S:8H:6D:TH:8H:3H:3H:QD:KS:7D:TC:6D:8C:TC:QH:3C:6C:TH:6C:AC:QH:9H:5D:4C:2C:2C:4H:7C:JC:7C:6C:8S:9C:5S:5S:JD:8S:2H:9D:KH:6S:TC:TH:KH:AD:5S:5D:QD:AH:4S:5D:QS:AS:3C:9S:9S:JC:3H:7S:KC:9H:8D:AD:8D:KS:TS:4H:2D:8H:TS:TS:JD:4C:7S:AC:3S:6D:QD:JD:QS:JS:QS:3D:2D:2D:8D:TS:3S:7D:JS:TS:6D:JH:AH:6H:8D:6C:8H:5S:4H:8C:6H:9C:4D:7H:QC:JS:AS:2H:6S:AS:4S:4H:7H:2S:6S:3H:2C:JC:4C:QD:9C:QC:JC:JH:8S:TD:JS:2H:9S:5C:7D:3D:3C:AC:JD:QC:KS:2S:5D:2S:4D:2C:6S:3C:AS:6S:TS"}

The player calculated hash from The Final Result
 'secret=3S:4D:KD:5H:JC:QD:8H:9H:7S:KD:5C:5D:TC:5H:TD:7C:KH:9H:3D:QC:JD:8D:KS:9C:7S:KC:KC:TD:7S:KC:KD:2D:AH:3H:6D:3H:7D:2C:7C:TH:AD:KD:5C:KC:3S:JS:7S:8S:TC:JH:4H:AC:KD:5H:3D:KS:5H:AC:2S:3D:7H:4S:3C:QC:6D:8C:6S:QH:7C:TH:JH:9S:4C:4D:AD:QS:9C:3C:QS:7D:TC:8C:TD:5H:AD:AH:4S:4D:QH:5C:9D:9S:9H:8C:2S:4H:5H:8H:TD:KD:9D:2D:AS:AD:7C:4C:6C:KS:8C:5S:5C:3D:5S:9H:TD:2H:JS:4D:8D:QH:TH:JC:AS:KH:JD:7D:3S:JH:6H:5D:6H:QH:7H:9S:6C:8S:7H:9D:AH:2H:QD:QC:KH:3S:KH:6H:2H:AH:AC:2D:6H:2C:5C:9D:4S:2S:9D:4C:QS:8S:9C:7H:JH:KC:4S:8H:6D:TH:8H:3H:3H:QD:KS:7D:TC:6D:8C:TC:QH:3C:6C:TH:6C:AC:QH:9H:5D:4C:2C:2C:4H:7C:JC:7C:6C:8S:9C:5S:5S:JD:8S:2H:9D:KH:6S:TC:TH:KH:AD:5S:5D:QD:AH:4S:5D:QS:AS:3C:9S:9S:JC:3H:7S:KC:9H:8D:AD:8D:KS:TS:4H:2D:8H:TS:TS:JD:4C:7S:AC:3S:6D:QD:JD:QS:JS:QS:3D:2D:2D:8D:TS:3S:7D:JS:TS:6D:JH:AH:6H:8D:6C:8H:5S:4H:8C:6H:9C:4D:7H:QC:JS:AS:2H:6S:AS:4S:4H:7H:2S:6S:3H:2C:JC:4C:QD:9C:QC:JC:JH:8S:TD:JS:2H:9S:5C:7D:3D:3C:AC:JD:QC:KS:2S:5D:2S:4D:2C:6S:3C:AS:6S:TS'
{"hash":"29c4f53a178f85f7c35479e662f1724fd554f1e35672fbc5a47f1f217b0fc5bf","result":""}

In this case the player was incorrect with verifying his round.