基于数字签名和数字水印技术的电子签章算法研究

将数字签名技术、数字水印技术和时间戳技术相结合提出了一种电子签章的实现算法。该算法在数字签名中添加时间戳信息，进一步提高了签章的安全性和抗攻击性。在签章算法中设计了一个基于小波分解信号的局部极大值的数字水印嵌入算法，可以将签名信息作为水印嵌入到签章图片中，增强了签章信息的隐蔽性。经过仿真实验，该方案能够较好地完成电子商务交易中的合同签章应用，实现身份认证和保证合同文本的完整性和不可篡改性。

Electronic signature algorithm based on digital signature and digital watermarking technology

An electronic signature algorithm, using a combined technology of digital signature, digital watermarking and time stamp, is presented. In this algorithm time, stamp information is added to digital signature data for improving the signature safety and anti-offensive. A digital watermark embedding algorithm based on wavelets transform module maximum is designed. By using this algorithm the signature information can be embedded into the signature image as a watermark, thus enhancing the imperceptibility. The experiment shows that the algorithm can meet the requirements of contract signature in e-commerce transactions, implements the identity authentication, and ensures the integrity and non-tampering of the contract.