eddsa_verify/4

Description

eddsa_verify/4 determines if a given signature is valid as per the EdDSA algorithm for the provided data, using the specified public key.

The signature is as follows:

eddsa_verify(+PubKey, +Data, +Signature, +Options) is semi-det

Where:

• PubKey is the encoded public key as a list of bytes.
• Data is the message to verify, represented as either a hexadecimal atom or a list of bytes. It's important that the message isn't pre-hashed since the Ed25519 algorithm processes messages in two passes when signing.
• Signature represents the signature corresponding to the data, provided as a list of bytes.
• Options are additional configurations for the verification process. Supported options include: encoding(+Format) which specifies the encoding used for the Data, and type(+Alg) which chooses the algorithm within the EdDSA family (see below for details).

For Format, the supported encodings are:

• hex (default), the hexadecimal encoding represented as an atom.
• octet, the plain byte encoding depicted as a list of integers ranging from 0 to 255.
• text, the plain text encoding represented as an atom.
• utf8 (default), the UTF-8 encoding represented as an atom.

For Alg, the supported algorithms are:

• ed25519 (default): The EdDSA signature scheme using SHA-512 (SHA-2) and Curve25519.

Examples

# Verify a signature for a given hexadecimal data.
- eddsa_verify([127, ...], '9b038f8ef6918cbb56040dfda401b56b...', [23, 56, ...], [encoding(hex), type(ed25519)])

# Verify a signature for binary data.
- eddsa_verify([127, ...], [56, 90, ..], [23, 56, ...], [encoding(octet), type(ed25519)])