Message Digest 2


Message Digest 2, or MD2, is a cryptographic hash function that was developed by Ronald Rivest in 1989. Primarily designed for 8-bit processors, MD2 produces a fixed-size, 128-bit hash value from an input message of variable length. While it is no longer considered secure due to advancements in computational capabilities, MD2 historically served as a widely-used method for ensuring data integrity in digital communication.

Key Takeaways

  1. Message Digest 2 (MD2) is an early cryptographic hash function that was developed in 1989 by Ronald Rivest, designed to create a fixed-size, unique hash output from inputted data for the purpose of verifying data integrity.
  2. MD2 is considered relatively slow as compared to other hashing algorithms and is not suitable for modern applications due to its vulnerability to various attacks, such as pre-image, collision, and second-pre-image attacks.
  3. Although MD2 has been declared obsolete and has been succeeded by more secure and efficient hashing algorithms like MD5, SHA-1, and SHA-256, it has historical significance as being one of the pioneer cryptographic hash functions in the field of data security.


Message Digest 2 (MD2) is an important technology term because it represents an early cryptographic hash function, designed by Ronald L.

Rivest in 1989.

As a one-way hashing algorithm, MD2 was primarily used for ensuring data integrity and security, and verifying that digital files or messages have not been altered or tampered with.

It converts an input message into a fixed-size, 128-bit hash value, making it difficult to recover the original message from the hash or create a different message with the same hash.

Although MD2 has been considered vulnerable to attacks and deprecated in favor of more secure algorithms like MD5 or SHA, it played a crucial role in the evolution of cryptographic techniques and contributed to the development of modern security and authentication systems.


Message Digest 2 (MD2), developed by Ronald Rivest in 1989, serves a vital role in the realm of data security and integrity assurance. The primary purpose of MD2 is to generate fixed-size hash values from input data, which is typically text or binary files. This cryptographic hash function is particularly suitable for applications where the security of digital data is paramount, such as confirming the integrity of files transmitted over the internet or validating digital signatures.

By producing unique fingerprints for the input data, MD2 helps detect any unauthorized tampering or modifications to the original information, thereby ensuring the security and authenticity of the data in question. While MD2 has largely been superseded by more advanced cryptographic hash functions such as MD5 and SHA-256, its significance in the evolution of data security cannot be understated. The algorithm works by processing the input data in blocks and utilizes a complex series of mathematical operations to generate the hash value.

This output, often represented as a string of alphanumeric characters, is then analyzed by the receiving party to confirm the data’s integrity. If the hash values match, it implies the transmitted data is genuine and unaltered, providing a layer of trust in digital transactions and communications. MD2 continues to hold relevance in the field of cryptography and serves as a testament to the ongoing advancements in data security and integrity assurance.

Examples of Message Digest 2

Message Digest 2 (MD2) is a cryptographic hash function developed in 1989 by Ronald Rivest. It’s an older and less secure method for creating a fixed-size, unique representation (hash) of input data. Here are three real world examples of its application:

Email Verification: In the early days of email communications, MD2 could have been used as a checksum mechanism to verify that emails were not tampered with during transmission. By computing the MD2 hash of the original email message and checking it against the MD2 hash of the email received by the recipient, one could ensure that the content had not been altered.

File Integrity Checking: MD2 might have been used in early file transfer protocols to check the integrity of files. When downloading a file from a server, the client could compare the file’s original MD2 hash with the hash of the downloaded file to make sure it was not corrupted or altered during the transfer process.

Password Storage: When users create password-protected accounts in older systems, those passwords can be hashed using the MD2 function before being stored in the database. While not as common or secure today, in the past, upon future login attempts, the system would hash the entered password to check if it matches the stored hashed password, granting or denying access accordingly.Nowadays, MD2 is considered outdated and insecure due to advances in technology and cryptography. As a result, it is no longer widely used in practice. More secure cryptographic hash functions like SHA-2 and SHA-3 have since replaced MD

Message Digest 2 FAQ

1. What is Message Digest 2 (MD2)?

Message Digest 2 (MD2) is a cryptographic hash function developed by Ronald Rivest in 1989. It produces a fixed-size hash value (128 bits) from an arbitrary-length input message. MD2 was designed to provide a secure and efficient way to verify the integrity of digital data.

2. Is MD2 still considered secure?

MD2 is no longer considered secure due to its slow performance and a number of discovered vulnerabilities. It has been surpassed by newer, more secure, and faster hash algorithms like SHA-256 and SHA-3. As a result, it’s not recommended to use MD2 for any security-related applications.

3. What are some common use cases for MD2?

Although MD2 is no longer considered secure, it was historically used for various applications, including data integrity verification, digital signatures, password storage, and message authentication codes. However, newer, more secure hash functions have since replaced MD2 in these use cases.

4. How does MD2 work?

MD2 processes the input message in 16-byte blocks, adding padding to ensure that the final block is full. After processing each block, it updates an internal state using a non-linear function and a table derived from the input data. Finally, the internal state is used to generate a 128-bit hash value representing the input message.

5. What are the main vulnerabilities of MD2?

Some of the main vulnerabilities of MD2 include its slow performance and susceptibility to various attacks, such as preimage attacks, second preimage attacks, and collision attacks. Over the years, multiple research papers have demonstrated successful attacks against MD2, which has led to it being considered insecure.

Related Technology Terms

  • Hash Function
  • Checksum
  • Data Integrity
  • Cryptographic Hash
  • MD2 Algorithm

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