The invention provides an information safety coprocessor for performing relevant operation by using a specific instruction set. The information safety coprocessor comprises a plurality of register files, an instruction processing unit, an operation unit, a direct memory access (DMA) engine, a local memory, a key memory and a context memory. The specific instruction set comprises a cryptographic algorithm execution instruction, a context operation instruction, a key access instruction, a data transmission instruction, a logical operation instruction and a register write instruction. Therefore, the information safety coprocessor has the advantages of function flexibility, low cost, high performance, multitask support and usability, and can meet complicated multifunction and multitask requirements with low cost.