4.1 Public Key Algorithms

Public key algorithms are used for encryption, decryption, signing and verification of signatures.

Data type: enum gpgme_pubkey_algo_t

The gpgme_pubkey_algo_t type specifies the set of all public key algorithms that are supported by GPGME. Possible values are:

GPGME_PK_RSA

This value indicates the RSA (Rivest, Shamir, Adleman) algorithm.

GPGME_PK_RSA_E

Deprecated. This value indicates the RSA (Rivest, Shamir, Adleman) algorithm for encryption and decryption only.

GPGME_PK_RSA_S

Deprecated. This value indicates the RSA (Rivest, Shamir, Adleman) algorithm for signing and verification only.

GPGME_PK_DSA

This value indicates DSA, the Digital Signature Algorithm.

GPGME_PK_ELG

This value indicates ElGamal.

GPGME_PK_ELG_E

This value also indicates ElGamal and is used specifically in GnuPG.

GPGME_PK_ECC

SINCE: 1.5.0

This value is a generic indicator for ellipic curve algorithms.

GPGME_PK_ECDSA

SINCE: 1.3.0

This value indicates ECDSA, the Elliptic Curve Digital Signature Algorithm as defined by FIPS 186-2 and RFC-6637.

GPGME_PK_ECDH

SINCE: 1.3.0

This value indicates ECDH, the Eliptic Curve Diffie-Hellmann encryption algorithm as defined by RFC-6637.

GPGME_PK_EDDSA

SINCE: 1.7.0

This value indicates the EdDSA algorithm.

Function: const char * gpgme_pubkey_algo_name (gpgme_pubkey_algo_t algo)

The function gpgme_pubkey_algo_name returns a pointer to a statically allocated string containing a description of the public key algorithm algo. This string can be used to output the name of the public key algorithm to the user.

If algo is not a valid public key algorithm, NULL is returned.

Function: char * gpgme_pubkey_algo_string (gpgme_subkey_t key)

SINCE: 1.7.0

The function gpgme_pubkey_algo_string is a convenience function to build and return an algorithm string in the same way GnuPG does (e.g. “rsa2048” or “ed25519”). The caller must free the result using gpgme_free. On error (e.g. invalid argument or memory exhausted), the function returns NULL and sets ERRNO.