.. index:: single: ed25519 .. _ed25519/0:

.. rst-class:: right

category

ed25519

Ed25519 (RFC 8032) public-key signature implementation. Requires exact, unbounded integer arithmetic for arithmetic modulo the 255-bit field prime and modulo the group order.

| Availability: | logtalk_load(crypto(loader))

| Author: Paulo Moura | Version: 1:0:0 | Date: 2026-08-02

| Compilation flags: | static

| Complements: | :ref:`crypto <crypto/0>` | Uses: | :ref:`list <list/0>` | :ref:`sha512 <sha512/0>` | :ref:`type <type/0>`

| Remarks: | (none)

| Inherited public predicates: | (none)

.. contents:: :local: :backlinks: top

Public predicates

.. index:: ed25519_keypair/2 .. _ed25519/0::ed25519_keypair/2:

ed25519_keypair/2 ^^^^^^^^^^^^^^^^^^^^^

Generates a fresh random 32-byte Seed and derives the corresponding 32-byte PublicKey. The seed is the value to keep secret and to pass to ed25519_sign/3; it is also sometimes called the "secret key". Available only on backends with unbounded integer arithmetic.

| Compilation flags: | static

| Template: | ed25519_keypair(Seed,PublicKey) | Mode and number of proofs: | ed25519_keypair(-list(byte),-list(byte)) - one

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.. index:: ed25519_public_key/2 .. _ed25519/0::ed25519_public_key/2:

ed25519_public_key/2 ^^^^^^^^^^^^^^^^^^^^^^^^

Derives the 32-byte PublicKey corresponding to a 32-byte Seed. Available only on backends with unbounded integer arithmetic.

| Compilation flags: | static

| Template: | ed25519_public_key(Seed,PublicKey) | Mode and number of proofs: | ed25519_public_key(+list(byte),-list(byte)) - one_or_error

| Exceptions: | Seed is a partial list or a list with an element which is a variable: | instantiation_error | Seed is neither a variable nor a list of 32 bytes: | type_error(list(byte,32),Seed) | Seed contains a non-integer byte: | type_error(integer,Byte) | Seed contains an integer outside the byte range: | domain_error(byte,Byte)

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.. index:: ed25519_sign/3 .. _ed25519/0::ed25519_sign/3:

ed25519_sign/3 ^^^^^^^^^^^^^^^^^^

Computes the 64-byte Ed25519 Signature of Message using Seed. Not constant-time; see the module-level note on this section. Available only on backends with unbounded integer arithmetic.

| Compilation flags: | static

| Template: | ed25519_sign(Seed,Message,Signature) | Mode and number of proofs: | ed25519_sign(+list(byte),+list(byte),-list(byte)) - one_or_error

| Exceptions: | Seed is a partial list or a list with an element which is a variable: | instantiation_error | Seed is neither a variable nor a list of 32 bytes: | type_error(list(byte,32),Seed) | Seed contains a non-integer byte: | type_error(integer,Byte) | Seed contains an integer outside the byte range: | domain_error(byte,Byte) | Message is a partial list or a list with an element which is a variable: | instantiation_error | Message is neither a variable nor a list of bytes: | type_error(list(byte),Message) | Message contains a non-integer byte: | type_error(integer,Byte) | Message contains an integer outside the byte range: | domain_error(byte,Byte)

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.. index:: ed25519_verify/3 .. _ed25519/0::ed25519_verify/3:

ed25519_verify/3 ^^^^^^^^^^^^^^^^^^^^

Succeeds if Signature is a valid Ed25519 signature of Message under PublicKey, and fails otherwise (invalid signature, non-canonical S, non-canonical or small-order PublicKey or R component, or malformed input lengths); see the module-level note on this section for the exact verification policy. Available only on backends with unbounded integer arithmetic.

| Compilation flags: | static

| Template: | ed25519_verify(PublicKey,Message,Signature) | Mode and number of proofs: | ed25519_verify(+list(byte),+list(byte),+list(byte)) - zero_or_one

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Protected predicates

(no local declarations; see entity ancestors if any)

Private predicates

(no local declarations; see entity ancestors if any)

Operators

(none)