This paper proposes practical non-interactive public key systems that allow organizations to use a single public key while ensuring that a threshold of participants must collaborate to decrypt messages. The system is based on the ElGamal cryptosystem and modified threshold schemes. In this approach, each organization has a single public key, and any individual within the company must obtain enough participants with the appropriate number of shadows to calculate the message. The system ensures that the secret key is not revealed to insiders or outsiders, making it more secure than traditional threshold schemes. The paper discusses two threshold schemes: one based on Lagrange interpolation and another based on geometry. The Lagrange interpolation method involves generating modified shadows that allow participants to compute partial results, which are then combined to decrypt the message. The geometric approach uses planes with public slopes to determine a secret point, where the intersection of t planes reveals the secret. The system is designed to be non-interactive, with each participant calculating their partial result and sending it to a designated individual. This individual then combines the partial results to decrypt the message. The paper also addresses security concerns, such as anonymity and the use of pseudonyms to prevent collusion among shadowholders. The paper also discusses enhancements to the system, including avoiding the use of Galois fields and ensuring anonymity. It concludes that the proposed system is secure and practical, allowing organizations to use a public key system while requiring a threshold of participants to decrypt messages. The system is based on the ElGamal cryptosystem and modified threshold schemes, and it is partially inspired by previous work in the field.This paper proposes practical non-interactive public key systems that allow organizations to use a single public key while ensuring that a threshold of participants must collaborate to decrypt messages. The system is based on the ElGamal cryptosystem and modified threshold schemes. In this approach, each organization has a single public key, and any individual within the company must obtain enough participants with the appropriate number of shadows to calculate the message. The system ensures that the secret key is not revealed to insiders or outsiders, making it more secure than traditional threshold schemes. The paper discusses two threshold schemes: one based on Lagrange interpolation and another based on geometry. The Lagrange interpolation method involves generating modified shadows that allow participants to compute partial results, which are then combined to decrypt the message. The geometric approach uses planes with public slopes to determine a secret point, where the intersection of t planes reveals the secret. The system is designed to be non-interactive, with each participant calculating their partial result and sending it to a designated individual. This individual then combines the partial results to decrypt the message. The paper also addresses security concerns, such as anonymity and the use of pseudonyms to prevent collusion among shadowholders. The paper also discusses enhancements to the system, including avoiding the use of Galois fields and ensuring anonymity. It concludes that the proposed system is secure and practical, allowing organizations to use a public key system while requiring a threshold of participants to decrypt messages. The system is based on the ElGamal cryptosystem and modified threshold schemes, and it is partially inspired by previous work in the field.