智能仪表适应新的欧洲标准

　　智能仪表适应新的欧洲标准

　　欧盟智能电网计划阐明了智能电表的技术规范，这些标准现在正在成为法定任务。严格的时间、安全和电源要求提出了具有挑战性的设计问题。新的MCU简化迁移路径。

　　欧洲联盟国家最近制定了将欧盟智能电网倡议纳入国家立法的法律。在德国，政府已决定改用智能计量2014，从而使能源供应商和电表制造商面临压力。能源经济法（“energiewirtschaftsgesetz，”EnWG）要求米必须反映实际能耗和实际使用时间，“从2010年1月开始（§21b）。能源供应商有义务创造每月，每季度或半年的总数，“他们也有提供“负荷变化或白天依赖关税”直到2010年12月（§40）。如果没有某种数据传输工具，这些法律义务很难满足。在这样的背景下，VDE最近发布计量装置两种规格。规格系列EDL（edl21和edl40）涵盖了德国4300万家持有米近似，而对称²（“同步模块表”）在商业和工业领域的目标。

　　Both specifications employ elliptic curve cryptography （ECC） for creating digital signatures on consumption measurement values. In particular， the Elliptic Curve Digital Signature Algorithm （ECDSA） guarantees the authenticity of remote meter readings. Compared to other algorithms， like RSA， ECC provides the same level of security with shorter keys， or more security when the key-length is kept equal. For instance， an ECDSA signature with a key-length of 192 bits is slightly more secure than 1024-bit RSA. This is of particular importance in the context of embedded systems， since shorter keys require less memory and less computational power， resulting in a significant performance and energy-efficiency gain. This is why the ANSI-standardized curve p192r1 serves as the base curve for digitally signing measurements on SyM² and EDL meters. However， SyM² meters face stringent timing requirements， as they need to perform two consumption measurements per second， sign and transmit them. In contrast， EDL meters have to meet rather relaxed timing requirements， a signature might take nearly three minutes to complete without raising any issues.

　　Therefore， ubisys® technologies has extended its C++ template class library CompactECC™ with a dedicated implementation of the p192r1 curve. This particular implementation allows for an optimal blend of code size， memory footprint， and execution time， depending on individual application requirements. The library can generally be used with all 8-， 16- and 32-bit controllers for which a C++ or embedded C++ compiler with template support exists. Integration with plain C projects is also possible.