Ethereum: Why Use DER Encoding for Signatures?

When it comes to signing messages on Ethereum, the choice of encoding scheme is crucial. One of the most common options is DER encoding, also known as Edward Reynolds Derivation (DER). However, using DER encoding for signatures can have significant implications.

In this article, we’ll look at why using DER encoding for signatures may not be necessary and what alternatives are available.

What is a Signature?

A signature in Ethereum is two 32-byte numbers: the message and its hash. This signature is used to prove that the sender of the transaction has control over all of the transaction data.

DER Encoding: A Brief History

DER encoding was introduced by Edward Reynolds as a more efficient alternative to traditional hexadecimal encoding schemes like PEM or Base64. However, it was not widely adopted until recently, and its use in Ethereum transactions is still relatively rare.

In the early days of Ethereum, signatures were encoded using the Public-Key Cryptography Mails (PEM) format, which was later replaced by DER encoding. While this change did not completely eliminate the need for DER encoding, it did make the transition easier.

Why Use DER Encoding for Signatures?

DER encoding offers several benefits over traditional hexadecimal encoding schemes:

• Efficiency: DER encoding is more compact than PEM or Base64 encoding, making it suitable for large transactions.

• Security: By using a single, concatenated signature (message and digest), the risk of a single component being compromised is reduced.

• Interoperability: DER encoding can be easily converted to other formats, such as PEM or Base64.

Disadvantages of Using DER Encoding for Signatures

While DER encoding offers advantages, it also has some significant disadvantages:

• Complexity: Using DER encoding adds an additional layer of complexity when signing transactions.

• Transparency: In the transaction format, the message and digest are already clearly presented. Adding another 6-7 bytes of DER encoded data may not be immediately obvious to other parties.

• Interoperability Limitations: DER encoding is specific to the Ethereum private key format and may not be compatible with other platforms or networks.

Alternatives to DER Encoding for Signatures

If you are having difficulty using DER encoding, consider the following alternatives:

• Base64: PEM or Base64 encoding can be used as an intermediate step, followed by DER encoding.

• PEM: The Public-Key Cryptography Mails (PEM) format is widely supported and offers a more traditional encoding scheme.

• JSON Web Tokens (JWT): JSON Web Tokens (JWT) is another popular alternative for signing messages on Ethereum.

Conclusion

While DER encoding offers some benefits, it is not the only option available. By understanding the trade-offs between DER encoding and other alternatives, you can make an informed decision about how to sign messages on Ethereum.

In this article, we explored why using DER encoding for signatures may not be necessary and what options are available. Whether you prefer PEM or Base64 encoding, or JWT as a more modern alternative, there is no need to sacrifice security and performance for convenience.