* cipher/Makefile.am: Add 'cipher-poly1305.c'.
* cipher/cipher-internal.h (gcry_cipher_handle): Add 'u_mode.poly1305'.
(_gcry_cipher_poly1305_encrypt, _gcry_cipher_poly1305_decrypt)
(_gcry_cipher_poly1305_setiv, _gcry_cipher_poly1305_authenticate)
(_gcry_cipher_poly1305_get_tag, _gcry_cipher_poly1305_check_tag): New.
* cipher/cipher-poly1305.c: New.
* cipher/cipher.c (_gcry_cipher_open_internal, cipher_setkey)
(cipher_reset, cipher_encrypt, cipher_decrypt, _gcry_cipher_setiv)
(_gcry_cipher_authenticate, _gcry_cipher_gettag)
(_gcry_cipher_checktag): Handle 'GCRY_CIPHER_MODE_POLY1305'.
(cipher_setiv): Move handling of 'GCRY_CIPHER_MODE_GCM' to ...
(_gcry_cipher_setiv): ... here, as with other modes.
* src/gcrypt.h.in: Add 'GCRY_CIPHER_MODE_POLY1305'.
* tests/basic.c (_check_poly1305_cipher, check_poly1305_cipher): New.
(check_ciphers): Add Poly1305 check.
(check_cipher_modes): Call 'check_poly1305_cipher'.
* tests/bench-slope.c (bench_gcm_encrypt_do_bench): Rename to
bench_aead_... and take nonce as argument.
(bench_gcm_decrypt_do_bench, bench_gcm_authenticate_do_bench): Ditto.
(bench_gcm_encrypt_do_bench, bench_gcm_decrypt_do_bench)
(bench_gcm_authenticate_do_bench, bench_poly1305_encrypt_do_bench)
(bench_poly1305_decrypt_do_bench)
(bench_poly1305_authenticate_do_bench, poly1305_encrypt_ops)
(poly1305_decrypt_ops, poly1305_authenticate_ops): New.
(cipher_modes): Add Poly1305.
(cipher_bench_one): Add special handling for Poly1305.