diff options
Diffstat (limited to 'lib/public_key/src')
-rw-r--r-- | lib/public_key/src/pubkey_cert_records.erl | 90 | ||||
-rw-r--r-- | lib/public_key/src/pubkey_pem.erl | 18 | ||||
-rw-r--r-- | lib/public_key/src/public_key.erl | 185 |
3 files changed, 218 insertions, 75 deletions
diff --git a/lib/public_key/src/pubkey_cert_records.erl b/lib/public_key/src/pubkey_cert_records.erl index 98004c71a3..3226aacb3f 100644 --- a/lib/public_key/src/pubkey_cert_records.erl +++ b/lib/public_key/src/pubkey_cert_records.erl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 2008-2012. All Rights Reserved. +%% Copyright Ericsson AB 2008-2013. All Rights Reserved. %% %% The contents of this file are subject to the Erlang Public License, %% Version 1.1, (the "License"); you may not use this file except in @@ -23,7 +23,8 @@ -include("public_key.hrl"). --export([decode_cert/1, transform/2, supportedPublicKeyAlgorithms/1]). +-export([decode_cert/1, transform/2, supportedPublicKeyAlgorithms/1, + supportedCurvesTypes/1, namedCurves/1]). %%==================================================================== %% Internal application API @@ -101,6 +102,77 @@ supportedPublicKeyAlgorithms(?'dhpublicnumber') -> 'DHPublicKey'; supportedPublicKeyAlgorithms(?'id-keyExchangeAlgorithm') -> 'KEA-PublicKey'; supportedPublicKeyAlgorithms(?'id-ecPublicKey') -> 'ECPoint'. +supportedCurvesTypes(?'characteristic-two-field') -> characteristic_two_field; +supportedCurvesTypes(?'prime-field') -> prime_field. + +namedCurves(?'sect571r1') -> sect571r1; +namedCurves(?'sect571k1') -> sect571k1; +namedCurves(?'sect409r1') -> sect409r1; +namedCurves(?'sect409k1') -> sect409k1; +namedCurves(?'secp521r1') -> secp521r1; +namedCurves(?'secp384r1') -> secp384r1; +namedCurves(?'secp224r1') -> secp224r1; +namedCurves(?'secp224k1') -> secp224k1; +namedCurves(?'secp192k1') -> secp192k1; +namedCurves(?'secp160r2') -> secp160r2; +namedCurves(?'secp128r2') -> secp128r2; +namedCurves(?'secp128r1') -> secp128r1; +namedCurves(?'sect233r1') -> sect233r1; +namedCurves(?'sect233k1') -> sect233k1; +namedCurves(?'sect193r2') -> sect193r2; +namedCurves(?'sect193r1') -> sect193r1; +namedCurves(?'sect131r2') -> sect131r2; +namedCurves(?'sect131r1') -> sect131r1; +namedCurves(?'sect283r1') -> sect283r1; +namedCurves(?'sect283k1') -> sect283k1; +namedCurves(?'sect163r2') -> sect163r2; +namedCurves(?'secp256k1') -> secp256k1; +namedCurves(?'secp160k1') -> secp160k1; +namedCurves(?'secp160r1') -> secp160r1; +namedCurves(?'secp112r2') -> secp112r2; +namedCurves(?'secp112r1') -> secp112r1; +namedCurves(?'sect113r2') -> sect113r2; +namedCurves(?'sect113r1') -> sect113r1; +namedCurves(?'sect239k1') -> sect239k1; +namedCurves(?'sect163r1') -> sect163r1; +namedCurves(?'sect163k1') -> sect163k1; +namedCurves(?'secp256r1') -> secp256r1; +namedCurves(?'secp192r1') -> secp192r1; + +namedCurves(sect571r1) -> ?'sect571r1'; +namedCurves(sect571k1) -> ?'sect571k1'; +namedCurves(sect409r1) -> ?'sect409r1'; +namedCurves(sect409k1) -> ?'sect409k1'; +namedCurves(secp521r1) -> ?'secp521r1'; +namedCurves(secp384r1) -> ?'secp384r1'; +namedCurves(secp224r1) -> ?'secp224r1'; +namedCurves(secp224k1) -> ?'secp224k1'; +namedCurves(secp192k1) -> ?'secp192k1'; +namedCurves(secp160r2) -> ?'secp160r2'; +namedCurves(secp128r2) -> ?'secp128r2'; +namedCurves(secp128r1) -> ?'secp128r1'; +namedCurves(sect233r1) -> ?'sect233r1'; +namedCurves(sect233k1) -> ?'sect233k1'; +namedCurves(sect193r2) -> ?'sect193r2'; +namedCurves(sect193r1) -> ?'sect193r1'; +namedCurves(sect131r2) -> ?'sect131r2'; +namedCurves(sect131r1) -> ?'sect131r1'; +namedCurves(sect283r1) -> ?'sect283r1'; +namedCurves(sect283k1) -> ?'sect283k1'; +namedCurves(sect163r2) -> ?'sect163r2'; +namedCurves(secp256k1) -> ?'secp256k1'; +namedCurves(secp160k1) -> ?'secp160k1'; +namedCurves(secp160r1) -> ?'secp160r1'; +namedCurves(secp112r2) -> ?'secp112r2'; +namedCurves(secp112r1) -> ?'secp112r1'; +namedCurves(sect113r2) -> ?'sect113r2'; +namedCurves(sect113r1) -> ?'sect113r1'; +namedCurves(sect239k1) -> ?'sect239k1'; +namedCurves(sect163r1) -> ?'sect163r1'; +namedCurves(sect163k1) -> ?'sect163k1'; +namedCurves(secp256r1) -> ?'secp256r1'; +namedCurves(secp192r1) -> ?'secp192r1'. + %%-------------------------------------------------------------------- %%% Internal functions %%-------------------------------------------------------------------- @@ -111,14 +183,24 @@ decode_supportedPublicKey(#'OTPSubjectPublicKeyInfo'{algorithm= PA = #'PublicKeyAlgorithm'{algorithm=Algo}, subjectPublicKey = {0,SPK0}}) -> Type = supportedPublicKeyAlgorithms(Algo), - {ok, SPK} = 'OTP-PUB-KEY':decode(Type, SPK0), + SPK = case Type of + 'ECPoint' -> #'ECPoint'{point = SPK0}; + _ -> {ok, SPK1} = 'OTP-PUB-KEY':decode(Type, SPK0), + SPK1 + end, #'OTPSubjectPublicKeyInfo'{subjectPublicKey = SPK, algorithm=PA}. encode_supportedPublicKey(#'OTPSubjectPublicKeyInfo'{algorithm= PA = #'PublicKeyAlgorithm'{algorithm=Algo}, subjectPublicKey = SPK0}) -> Type = supportedPublicKeyAlgorithms(Algo), - {ok, SPK} = 'OTP-PUB-KEY':encode(Type, SPK0), + SPK = case Type of + 'ECPoint' -> + SPK0#'ECPoint'.point; + _ -> + {ok, SPK1} = 'OTP-PUB-KEY':encode(Type, SPK0), + SPK1 + end, #'OTPSubjectPublicKeyInfo'{subjectPublicKey = {0,SPK}, algorithm=PA}. %%% Extensions diff --git a/lib/public_key/src/pubkey_pem.erl b/lib/public_key/src/pubkey_pem.erl index 6bdc35fb79..c0a0de815b 100644 --- a/lib/public_key/src/pubkey_pem.erl +++ b/lib/public_key/src/pubkey_pem.erl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 2008-2012. All Rights Reserved. +%% Copyright Ericsson AB 2008-2013. All Rights Reserved. %% %% The contents of this file are subject to the Erlang Public License, %% Version 1.1, (the "License"); you may not use this file except in @@ -202,7 +202,11 @@ pem_start('CertificationRequest') -> pem_start('ContentInfo') -> <<"-----BEGIN PKCS7-----">>; pem_start('CertificateList') -> - <<"-----BEGIN X509 CRL-----">>. + <<"-----BEGIN X509 CRL-----">>; +pem_start('OTPEcpkParameters') -> + <<"-----BEGIN EC PARAMETERS-----">>; +pem_start('ECPrivateKey') -> + <<"-----BEGIN EC PRIVATE KEY-----">>. pem_end(<<"-----BEGIN CERTIFICATE-----">>) -> <<"-----END CERTIFICATE-----">>; @@ -226,6 +230,10 @@ pem_end(<<"-----BEGIN PKCS7-----">>) -> <<"-----END PKCS7-----">>; pem_end(<<"-----BEGIN X509 CRL-----">>) -> <<"-----END X509 CRL-----">>; +pem_end(<<"-----BEGIN EC PARAMETERS-----">>) -> + <<"-----END EC PARAMETERS-----">>; +pem_end(<<"-----BEGIN EC PRIVATE KEY-----">>) -> + <<"-----END EC PRIVATE KEY-----">>; pem_end(_) -> undefined. @@ -250,7 +258,11 @@ asn1_type(<<"-----BEGIN CERTIFICATE REQUEST-----">>) -> asn1_type(<<"-----BEGIN PKCS7-----">>) -> 'ContentInfo'; asn1_type(<<"-----BEGIN X509 CRL-----">>) -> - 'CertificateList'. + 'CertificateList'; +asn1_type(<<"-----BEGIN EC PARAMETERS-----">>) -> + 'OTPEcpkParameters'; +asn1_type(<<"-----BEGIN EC PRIVATE KEY-----">>) -> + 'ECPrivateKey'. pem_decrypt() -> <<"Proc-Type: 4,ENCRYPTED">>. diff --git a/lib/public_key/src/public_key.erl b/lib/public_key/src/public_key.erl index 736c18cdd4..648dba3d5a 100644 --- a/lib/public_key/src/public_key.erl +++ b/lib/public_key/src/public_key.erl @@ -35,6 +35,8 @@ encrypt_public/2, encrypt_public/3, decrypt_public/2, decrypt_public/3, sign/3, verify/4, + generate_key/1, + compute_key/2, compute_key/3, pkix_sign/2, pkix_verify/2, pkix_sign_types/1, pkix_is_self_signed/1, @@ -52,6 +54,7 @@ -type public_crypt_options() :: [{rsa_pad, rsa_padding()}]. -type rsa_digest_type() :: 'md5' | 'sha'| 'sha224' | 'sha256' | 'sha384' | 'sha512'. -type dss_digest_type() :: 'none' | 'sha'. %% None is for backwards compatibility +-type ecdsa_digest_type() :: 'sha'| 'sha224' | 'sha256' | 'sha384' | 'sha512'. -type crl_reason() :: unspecified | keyCompromise | cACompromise | affiliationChanged | superseded | cessationOfOperation | certificateHold | privilegeWithdrawn | aACompromise. -type oid() :: tuple(). @@ -94,7 +97,9 @@ pem_entry_decode({'SubjectPublicKeyInfo', Der, _}) -> der_decode(KeyType, Key0); 'DSAPublicKey' -> {params, DssParams} = der_decode('DSAParams', Params), - {der_decode(KeyType, Key0), DssParams} + {der_decode(KeyType, Key0), DssParams}; + 'ECPoint' -> + der_decode(KeyType, Key0) end; pem_entry_decode({Asn1Type, Der, not_encrypted}) when is_atom(Asn1Type), is_binary(Der) -> @@ -251,10 +256,9 @@ decrypt_private(CipherText, privateExponent = D} = Key, Options) when is_binary(CipherText), - is_integer(N), is_integer(E), is_integer(D), is_list(Options) -> Padding = proplists:get_value(rsa_pad, Options, rsa_pkcs1_padding), - crypto:rsa_private_decrypt(CipherText, format_rsa_private_key(Key), Padding). + crypto:private_decrypt(rsa, CipherText, format_rsa_private_key(Key), Padding). %%-------------------------------------------------------------------- -spec decrypt_public(CipherText :: binary(), rsa_public_key() | rsa_private_key()) -> @@ -318,30 +322,41 @@ encrypt_private(PlainText, Options) when is_binary(PlainText), is_integer(N), is_integer(E), is_integer(D), - is_list(Options) -> + is_list(Options) -> Padding = proplists:get_value(rsa_pad, Options, rsa_pkcs1_padding), - crypto:rsa_private_encrypt(PlainText, format_rsa_private_key(Key), Padding). + crypto:private_encrypt(rsa, PlainText, format_rsa_private_key(Key), Padding). +%%-------------------------------------------------------------------- +-spec generate_key(#'DHParameter'{} | {namedCurve, Name ::atom()} | + #'ECParameters'{}) -> {Public::binary(), Private::binary()} | + #'ECPrivateKey'{}. +%% Description: Generates a new keypair +%%-------------------------------------------------------------------- +generate_key(#'DHParameter'{prime = P, base = G}) -> + crypto:generate_key(dh, [P, G]); +generate_key({namedCurve, _} = Params) -> + ec_generate_key(Params); +generate_key(#'ECParameters'{} = Params) -> + ec_generate_key(Params). -format_rsa_private_key(#'RSAPrivateKey'{modulus = N, publicExponent = E, - privateExponent = D, - prime1 = P1, prime2 = P2, - exponent1 = E1, exponent2 = E2, - coefficient = C}) - when is_integer(P1), is_integer(P2), - is_integer(E1), is_integer(E2), is_integer(C) -> - [crypto:mpint(K) || K <- [E, N, D, P1, P2, E1, E2, C]]; +%%-------------------------------------------------------------------- +-spec compute_key(#'ECPoint'{} , #'ECPrivateKey'{}) -> binary(). +-spec compute_key(OthersKey ::binary(), MyKey::binary(), #'DHParameter'{}) -> binary(). +%% Description: Compute shared secret +%%-------------------------------------------------------------------- +compute_key(#'ECPoint'{point = Point}, #'ECPrivateKey'{privateKey = PrivKey, + parameters = Param}) -> + ECCurve = ec_curve_spec(Param), + crypto:compute_key(ecdh, Point, list2int(PrivKey), ECCurve). -format_rsa_private_key(#'RSAPrivateKey'{modulus = N, publicExponent = E, - privateExponent = D}) -> - [crypto:mpint(K) || K <- [E, N, D]]. +compute_key(PubKey, PrivKey, #'DHParameter'{prime = P, base = G}) -> + crypto:compute_key(dh, PubKey, PrivKey, [P, G]). %%-------------------------------------------------------------------- - -spec pkix_sign_types(SignatureAlg::oid()) -> %% Relevant dsa digest type is subpart of rsa digest type { DigestType :: rsa_digest_type(), - SignatureType :: rsa | dsa + SignatureType :: rsa | dsa | ecdsa }. %% Description: %%-------------------------------------------------------------------- @@ -362,68 +377,60 @@ pkix_sign_types(?md5WithRSAEncryption) -> pkix_sign_types(?'id-dsa-with-sha1') -> {sha, dsa}; pkix_sign_types(?'id-dsaWithSHA1') -> - {sha, dsa}. + {sha, dsa}; +pkix_sign_types(?'ecdsa-with-SHA1') -> + {sha, ecdsa}; +pkix_sign_types(?'ecdsa-with-SHA256') -> + {sha256, ecdsa}; +pkix_sign_types(?'ecdsa-with-SHA384') -> + {sha384, ecdsa}; +pkix_sign_types(?'ecdsa-with-SHA512') -> + {sha512, ecdsa}. %%-------------------------------------------------------------------- --spec sign(binary() | {digest, binary()}, rsa_digest_type() | dss_digest_type(), +-spec sign(binary() | {digest, binary()}, rsa_digest_type() | dss_digest_type() | ecdsa_digest_type(), rsa_private_key() | - dsa_private_key()) -> Signature :: binary(). + dsa_private_key() | ec_private_key()) -> Signature :: binary(). %% Description: Create digital signature. %%-------------------------------------------------------------------- -sign({digest,_}=Digest, DigestType, Key = #'RSAPrivateKey'{}) -> - crypto:rsa_sign(DigestType, Digest, format_rsa_private_key(Key)); +sign(DigestOrPlainText, DigestType, Key = #'RSAPrivateKey'{}) -> + crypto:sign(rsa, DigestType, DigestOrPlainText, format_rsa_private_key(Key)); -sign(PlainText, DigestType, Key = #'RSAPrivateKey'{}) -> - crypto:rsa_sign(DigestType, sized_binary(PlainText), format_rsa_private_key(Key)); +sign(DigestOrPlainText, sha, #'DSAPrivateKey'{p = P, q = Q, g = G, x = X}) -> + crypto:sign(dss, sha, DigestOrPlainText, [P, Q, G, X]); -sign({digest,_}=Digest, sha, #'DSAPrivateKey'{p = P, q = Q, g = G, x = X}) -> - crypto:dss_sign(Digest, - [crypto:mpint(P), crypto:mpint(Q), - crypto:mpint(G), crypto:mpint(X)]); - -sign(PlainText, sha, #'DSAPrivateKey'{p = P, q = Q, g = G, x = X}) -> - crypto:dss_sign(sized_binary(PlainText), - [crypto:mpint(P), crypto:mpint(Q), - crypto:mpint(G), crypto:mpint(X)]); +sign(DigestOrPlainText, DigestType, #'ECPrivateKey'{privateKey = PrivKey, + parameters = Param}) -> + ECCurve = ec_curve_spec(Param), + crypto:sign(ecdsa, DigestType, DigestOrPlainText, [list2int(PrivKey), ECCurve]); %% Backwards compatible sign(Digest, none, #'DSAPrivateKey'{} = Key) -> sign({digest,Digest}, sha, Key). %%-------------------------------------------------------------------- --spec verify(binary() | {digest, binary()}, rsa_digest_type() | dss_digest_type(), +-spec verify(binary() | {digest, binary()}, rsa_digest_type() | dss_digest_type() | ecdsa_digest_type(), Signature :: binary(), rsa_public_key() - | dsa_public_key()) -> boolean(). + | dsa_public_key() | ec_public_key()) -> boolean(). %% Description: Verifies a digital signature. %%-------------------------------------------------------------------- -verify({digest,_}=Digest, DigestType, Signature, +verify(DigestOrPlainText, DigestType, Signature, #'RSAPublicKey'{modulus = Mod, publicExponent = Exp}) -> - crypto:rsa_verify(DigestType, Digest, - sized_binary(Signature), - [crypto:mpint(Exp), crypto:mpint(Mod)]); + crypto:verify(rsa, DigestType, DigestOrPlainText, Signature, + [Exp, Mod]); -verify(PlainText, DigestType, Signature, - #'RSAPublicKey'{modulus = Mod, publicExponent = Exp}) -> - crypto:rsa_verify(DigestType, - sized_binary(PlainText), - sized_binary(Signature), - [crypto:mpint(Exp), crypto:mpint(Mod)]); +verify(DigestOrPlaintext, DigestType, Signature, {#'ECPoint'{point = Point}, Param}) -> + ECCurve = ec_curve_spec(Param), + crypto:verify(ecdsa, DigestType, DigestOrPlaintext, Signature, [Point, ECCurve]); -verify({digest,_}=Digest, sha, Signature, {Key, #'Dss-Parms'{p = P, q = Q, g = G}}) - when is_integer(Key), is_binary(Signature) -> - crypto:dss_verify(Digest, sized_binary(Signature), - [crypto:mpint(P), crypto:mpint(Q), - crypto:mpint(G), crypto:mpint(Key)]); %% Backwards compatibility verify(Digest, none, Signature, {_, #'Dss-Parms'{}} = Key ) -> verify({digest,Digest}, sha, Signature, Key); -verify(PlainText, sha, Signature, {Key, #'Dss-Parms'{p = P, q = Q, g = G}}) - when is_integer(Key), is_binary(PlainText), is_binary(Signature) -> - crypto:dss_verify(sized_binary(PlainText), - sized_binary(Signature), - [crypto:mpint(P), crypto:mpint(Q), - crypto:mpint(G), crypto:mpint(Key)]). +verify(DigestOrPlainText, sha = DigestType, Signature, {Key, #'Dss-Parms'{p = P, q = Q, g = G}}) + when is_integer(Key), is_binary(Signature) -> + crypto:verify(dss, DigestType, DigestOrPlainText, Signature, [P, Q, G, Key]). + %%-------------------------------------------------------------------- -spec pkix_sign(#'OTPTBSCertificate'{}, rsa_private_key() | dsa_private_key()) -> Der::binary(). @@ -446,7 +453,7 @@ pkix_sign(#'OTPTBSCertificate'{signature = %%-------------------------------------------------------------------- -spec pkix_verify(Cert::binary(), rsa_public_key()| - dsa_public_key()) -> boolean(). + dsa_public_key() | ec_public_key()) -> boolean(). %% %% Description: Verify pkix x.509 certificate signature. %%-------------------------------------------------------------------- @@ -458,7 +465,12 @@ pkix_verify(DerCert, {Key, #'Dss-Parms'{}} = DSAKey) pkix_verify(DerCert, #'RSAPublicKey'{} = RSAKey) when is_binary(DerCert) -> {DigestType, PlainText, Signature} = pubkey_cert:verify_data(DerCert), - verify(PlainText, DigestType, Signature, RSAKey). + verify(PlainText, DigestType, Signature, RSAKey); + +pkix_verify(DerCert, Key = {#'ECPoint'{}, _}) + when is_binary(DerCert) -> + {DigestType, PlainText, Signature} = pubkey_cert:verify_data(DerCert), + verify(PlainText, DigestType, Signature, Key). %%-------------------------------------------------------------------- -spec pkix_is_issuer(Cert :: der_encoded()| #'OTPCertificate'{} | #'CertificateList'{}, @@ -640,13 +652,11 @@ do_pem_entry_decode({Asn1Type,_, _} = PemEntry, Password) -> encrypt_public(PlainText, N, E, Options)-> Padding = proplists:get_value(rsa_pad, Options, rsa_pkcs1_padding), - crypto:rsa_public_encrypt(PlainText, [crypto:mpint(E),crypto:mpint(N)], - Padding). + crypto:public_encrypt(rsa, PlainText, [E,N], Padding). -decrypt_public(CipherText, N,E, Options) -> +decrypt_public(CipherText, N,E, Options) -> Padding = proplists:get_value(rsa_pad, Options, rsa_pkcs1_padding), - crypto:rsa_public_decrypt(CipherText,[crypto:mpint(E), crypto:mpint(N)], - Padding). + crypto:public_decrypt(rsa, CipherText,[E, N], Padding). path_validation([], #path_validation_state{working_public_key_algorithm = Algorithm, @@ -732,10 +742,6 @@ validate(Cert, #path_validation_state{working_issuer_name = Issuer, pubkey_cert:prepare_for_next_cert(OtpCert, ValidationState). -sized_binary(Binary) -> - Size = size(Binary), - <<?UINT32(Size), Binary/binary>>. - otp_cert(Der) when is_binary(Der) -> pkix_decode_cert(Der, otp); otp_cert(#'OTPCertificate'{} =Cert) -> @@ -842,3 +848,46 @@ combine(CRL, DeltaCRLs) -> end, lists:foldl(Fun, hd(Deltas), tl(Deltas)) end. + +format_rsa_private_key(#'RSAPrivateKey'{modulus = N, publicExponent = E, + privateExponent = D, + prime1 = P1, prime2 = P2, + exponent1 = E1, exponent2 = E2, + coefficient = C}) + when is_integer(N), is_integer(E), is_integer(D), + is_integer(P1), is_integer(P2), + is_integer(E1), is_integer(E2), is_integer(C) -> + [E, N, D, P1, P2, E1, E2, C]; + +format_rsa_private_key(#'RSAPrivateKey'{modulus = N, publicExponent = E, + privateExponent = D}) when is_integer(N), + is_integer(E), + is_integer(D) -> + [E, N, D]. + +ec_generate_key(Params) -> + Curve = ec_curve_spec(Params), + Term = crypto:generate_key(ecdh, Curve), + ec_key(Term, Params). + +ec_curve_spec( #'ECParameters'{fieldID = FieldId, curve = PCurve, base = Base, order = Order, cofactor = CoFactor }) -> + Field = {pubkey_cert_records:supportedCurvesTypes(FieldId#'FieldID'.fieldType), + FieldId#'FieldID'.parameters}, + Curve = {erlang:list_to_binary(PCurve#'Curve'.a), erlang:list_to_binary(PCurve#'Curve'.b), none}, + {Field, Curve, erlang:list_to_binary(Base), Order, CoFactor}; +ec_curve_spec({namedCurve, OID}) -> + pubkey_cert_records:namedCurves(OID). + +ec_key({PrivateKey, PubKey}, Params) -> + #'ECPrivateKey'{version = 1, + privateKey = int2list(PrivateKey), + parameters = Params, + publicKey = {0, PubKey}}. + +list2int(L) -> + S = length(L) * 8, + <<R:S/integer>> = erlang:iolist_to_binary(L), + R. +int2list(I) -> + L = (length(integer_to_list(I, 16)) + 1) div 2, + binary_to_list(<<I:(L*8)>>). |