Here’s a draft article on “Ethereum: PEM format for ECDSA”:

Ethereum: PEM Format for ECDSA

When working with cryptographic keys, including those for the Ethereum network, it’s essential to understand how to format them securely. One important aspect of key formatting is the use of Public Key Encryption (PKE) algorithms such as Elliptic Curve Digital Signature Algorithm (ECDSA).

In this article, we’ll take a closer look at PEM format and its application in ECDSA for Ethereum.

What is PEM Format?

PEM (Pretty Easy Mail) format is a widely used standard for encoding public-private key pairs. It’s based on the ASCII character set and uses simple text-based syntax to represent cryptographic keys.

ECDSA Key Formats

ECDSA keys are typically represented as a pair of bytes, which can be encoded in PEM format using the following format:

-----BEGIN ECDSA PRIVATE KEY-----

MIIBIjANBgkqhkiG9w0BAQEFAASCAFgTwJL6U4yZz/...

-----END ECDSA PRIVATE KEY-----

Here’s a breakdown of each part:

• -----BEGIN indicates the start of a public key block.

• ECDSA is the name of the PKE algorithm being used (in this case, Elliptic Curve Digital Signature Algorithm).

• PRIVATE KEY encodes the private key in PEM format. The bytes are prefixed with - to indicate they are part of an ECDSA signature.

• The following line is a checksum that confirms the integrity of the data.

Private Key Format

The private key is typically represented as a string, which can be encoded in PEM format using:

-----BEGIN ECDSA PRIVATE KEY-----

MIIBIjANBgkqhkiG9w0BAQEFAASCAFgTwJL6U4yZz/...

This format includes the following elements:

• -----BEGIN indicates the start of a public key block.

• -ECDSA- is the name of the PKE algorithm being used (in this case, ECDSA).

• PRIVATE KEY encodes the private key in PEM format.

Public Key Format

The public key is typically represented as:

-----BEGIN PUBLIC KEY-----

...

-----END PUBLIC KEY-----

This format includes:

• -----BEGIN indicates the start of a public key block.

• - separates the public and private keys.

• The following line is the public key itself, which can be encoded in PEM format using:

...public_key_here...

Working with PEM Format in Python-ecdsa

When working with ECDSA for Ethereum, you’ll need to import the ecdsa library and use its functions to work with private and public keys. Here’s an example code snippet that demonstrates how to encode a private key in PEM format:

from ecdsa import signing

from cryptography.hazmat.primitives import serialization



Generate a new private key

private_key = signing.SigningKey.generate()



Encode the private key in PEM format

pem_private_key = private_key.to_string().encode()

print(pem_private_key)



Load the private key from a file (in PEM format)

private_key_from_file = serialization.load_pem_private_key(

    pem_private_key,

    password=None,

    backend='secrets'

)



Decode the loaded private key in PEM format

loaded_private_key = private_key_from_file.to_string().decode()


print(loaded_private_key)

This code snippet generates a new private key, encodes it in PEM format using to_string() and prints the output. It then loads the private key from a file (in PEM format) using load_pem_private_key() and decodes the loaded private key to display.

Conclusion

In this article, we explored PEM format and its application in ECDSA for Ethereum. By understanding how to encode private and public keys in PEM format, you can securely store and transmit cryptographic keys for your Ethereum projects. Remember to always use a secure password or authentication mechanism when working with private keys to prevent unauthorized access.

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