Cryptography refers to the process of converting plain text into different forms only recognizable and retrievable by intended recipients. It involves the use of encryption, which makes use of algorithms that either lock or unlock the scrambled message or data. Cryptography enables individuals to communicate publicly without fear of interference by third-parties who may want to mess with the integrity of the information in transit. The process makes use of a key, only available to the sender and recipient of the data, to encrypt data on one end, and, decrypt it on the other.
Blockchain, on the other hand, is a pile of records in the form of blocks, which is continually growing and impossible to alter, unless the alteration involves the whole chain. The structure, made to resist modification of any kind, consists of transactions that are easily retrievable and reliable, as they also include timestamps. Blockchains used as ledgers are under the control of a network formed by two computers in communication (Nofer et al., 2017). This system functions to validate the authenticity and integrity of newly added blocks into the already existing chain.
Blockchains differ significantly to cryptography although the two intersect in their functionalities. Blockchains is the technology that makes use of distributed ledgers. Every chain has a string of blocks that contain data. On the other hand, cryptography is the method used to ensure that the message in the single blocks remains difficult to alter unless there seems to be an agreement throughout the network which will grant modification. Cryptography uses a key, whether public or private that can change information into a form only the intended person can understand. It is a method of making the information useless to adversaries. Blockchains highly depend on cryptography to secure the integrity and confidentiality of Blockchains which are to remain retrievable and confidential.
Nofer, M., Gomber, P., Hinz, O., & Schiereck, D. (2017). Blockchain. Business & Information Systems Engineering, 59(3), 183-187.