* guix/pk-crypto.scm (gcrypt-version): New procedure.
* guix/scripts/archive.scm (%key-generation-parameters): New variable.
(%options) <generate-key>: Use it.
* tests/pk-crypto.scm ("sign + verify, Ed25519"): Skip if using gcrypt < 1.6.0.
* guix/pk-crypto.scm (bytevector->hash-data): Add #:key-type parameter.
Use the 'pkcs1' flag when KEY-TYPE is 'rsa', and 'rfc6979' when
KEY-TYPE is 'ecc' or 'dsa'.
(key-type): New procedure.
* guix/scripts/authenticate.scm (read-hash-data): Add 'key-type'
parameter. Pass it to 'bytevector->hash-data'. Adjust caller
accordingly.
* tests/pk-crypto.scm (%ecc-key-pair): New variable.
("key-type"): New test.
("sign + verify"): Pass #:key-type to 'bytevector->hash-data'.
("sign + verify, Ed25519"): New test.
* guix/pk-crypto.scm (token-string?): New procedure.
(canonical-sexp-nth-data): Return a symbol when the element is a
"token", and a bytevector otherwise.
(latin1-string->bytevector): Remove.
(hash-data->bytevector): Adjust accordingly.
* tests/pk-crypto.scm ("canonical-sexp-nth"): Adjust accordingly. Add
octet string example.
* guix/pk-crypto.scm: Rename procedures, variables, etc. from
'gcry-sexp' to 'canonical-sexp'. Add comment with references.
* guix/scripts/authenticate.scm, tests/pk-crypto.scm: Adjust
accordingly.
Ludovic Courtès