The goal of the paper is to discuss some possibilities of effective implementing cryptographic algorithms in software development. There are concerned two aspects of the term “effectiveness”: efficacy (i.e., meeting a goal of using cryptographic algorithms – providing a protection of information) and efficiency (i.e., implementing cryptographic algorithms in an economical way; as well as implementing cryptographic algorithms to the effect that they execute in an economical way). In the paper, there are defined and classified errors which are the causes of possible vulnerabilities in implementation of cryptographic algorithms on a computer. There are given general recommendations, how to escape from these vulnerabilities. There is also considered implementation of cryptographic algorithms in software development by using software libraries and frameworks. Several widespread software frameworks which provide cryptographic functionality are compared with each other by the speed of execution of algorithms. Finally, there are discussed some possibilities of maximising the speed of execution of cryptographic algorithms, emphasising the importance of parallelisation of algorithms. For block ciphers, possible parallelisation is discussed especially deeply, referencing the results obtained in practical experiments that demonstrate and estimate the benefits of parallelising block ciphers.