A method of generating at least one encryption key (130) for encrypting data (142), a method of 5 data transmission between at least two communication systems (136, 138), a method of encrypting data (142) and a method of decrypting encrypted data (144) are disclosed. Further disclosed are an encryption key generating device (110), a system (134), a data encryption system (148) and a data decryption system (150). The method of generating at least one encryption key (130) for encrypting data (142), specifically for data transmission over an insecure channel, comprises: i. blending at least two materials (114) according to at least one item of blending in-formation by using a blending device (112), thereby generating at least one blend (120); ii. detecting at least one material property (124) of the blend (120) by using at least one detector (126); and iii. transforming the material property (124) into the encryption key (130) by using at least one data processing device (132) configured for applying at least one trans-formation algorithm to the material property (124).