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eddsa_verify/4

Module​

This predicate is provided by crypto.pl.

Load this module before using the predicate:

:- consult('/v1/lib/crypto.pl').

Description​

Succeeds when Signature is a valid EdDSA signature for Data and PubKey.

PubKey and Signature are lists of bytes.

Options may be a single option term or a list of option terms:

  • type(+Algorithm) selects ed25519 (default);
  • encoding(+Encoding) selects how Data is interpreted, defaulting to hex.

Supported encodings are hex, octet, utf8, and text.

Signature​

eddsa_verify(+PubKey, +Data, +Signature, +Options) is semidet

Examples​

Verify an Ed25519 signature with default options​

This scenario demonstrates how to verify an Ed25519 signature over hexadecimal data.

Here are the steps of the scenario:

  • Given the program:
valid_ed25519(Verified) :-
  hex_bytes('53167ac3fc4b720daa45b04fc73fe752578fa23a10048422d6904b7f4f7bba5a', PubKey),
  hex_bytes('889bcfd331e8e43b5ebf430301dffb6ac9e2fce69f6227b43552fe3dc8cc1ee00c1cc53452a8712e9d5f80086dff8cf4999c1b93ed6c6e403c09334cb61ddd0b', Signature),
  eddsa_verify(PubKey, '9b038f8ef6918cbb56040dfda401b56bb1ce79c472e7736e8677758c83367a9d', Signature, []),
  Verified = true.
  • Given the query:
consult('/v1/lib/crypto.pl'),
valid_ed25519(Verified).
  • When the query is run
  • Then the answer we get is:
height: 42
gas_used: 235381
answer:
  has_more: false
  variables: ["Verified"]
  results:
  - substitutions:
    - variable: Verified
      expression: true

Reject an invalid Ed25519 signature​

This scenario demonstrates that eddsa_verify/4 fails when the signature does not match the data.

Here are the steps of the scenario:

  • Given the program:
invalid_ed25519 :-
  hex_bytes('53167ac3fc4b720daa45b04fc73fe752578fa23a10048422d6904b7f4f7bba5a', PubKey),
  hex_bytes('889bcfd331e8e43b5ebf430301dffb6ac9e2fce69f6227b43552fe3dc8cc1ee00c1cc53452a8712e9d5f80086dff8cf4999c1b93ed6c6e403c09334cb61ddd0b', Signature),
  eddsa_verify(PubKey, '9b038f8ef6918cbb56040dfda401b56bb1ce79c472e7736e8677758c83367a9e', Signature, []).
  • Given the query:
consult('/v1/lib/crypto.pl'),
invalid_ed25519.
  • When the query is run
  • Then the answer we get is:
height: 42
gas_used: 235349
answer:
  has_more: false
  variables:
  results:

Reject an unsupported EdDSA algorithm​

This scenario demonstrates that eddsa_verify/4 rejects algorithms outside the EdDSA family.

Here are the steps of the scenario:

  • Given the program:
unsupported_eddsa :-
  eddsa_verify([], '', [], [type(secp256k1)]).
  • Given the query:
consult('/v1/lib/crypto.pl'),
unsupported_eddsa.
  • When the query is run
  • Then the answer we get is:
height: 42
gas_used: 4809
answer:
  has_more: false
  variables:
  results:
  - error: "error(type_error(cryptographic_algorithm,secp256k1),eddsa_verify/4)"
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