Real-time geospatial data protection requires efficient, collision-resistant cryptographic algorithms tailored to constraints of streaming data transmission. The authors present a novel stream cipher scheme built upon group-theoretic constructions. The proposed approach leverages the combinatorial group theory, employing a pair of non-commuting elements from the amalgamated subgroup of a free product of groups as the key. One element acts as a multiplier, while the second one yields an inner automorphism of the amalgamated subgroups. To encode the plaintext, the alphabet is formed from representative elements of the right cosets that lie outside the said subgroups. The practical viability of utilizing group amalgams as a platform is guaranteed by existence of a canonical normal form in a free product with amalgamation. We provide a complete mathematical formulation of the cipher`s operation. To demonstrate the practical implementation of the encryption and decryption mechanisms, a comprehensive example is provided using an amalgam of alternating groups with amalgamated subgroups of permutation ones. The scientific novelty is in the original method of alphabet formation, the key space design based on free products of groups with an amalgamated subgroup, and a unique one-way function. The one-way property of the encryption function stems from the high computational complexity of restoring the plaintext written in normal form not knowing the secret key