.TH public_key 3erl "public_key 1.3" "Ericsson AB" "Erlang Module Definition"
.SH NAME
public_key \- API module for public-key infrastructure.
.SH DESCRIPTION
.LP
Provides functions to handle public-key infrastructure, for details see \fBpublic_key(7)\fR\&\&.
.SH "DATA TYPES"

.LP

.RS -4
.B
Note:
.RE
All records used in this Reference Manual are generated from ASN\&.1 specifications and are documented in the User\&'s Guide\&. See \fBPublic-key Records\fR\&\&.

.LP
Use the following include directive to get access to the records and constant macros described here and in the User\&'s Guide:
.LP
.nf
 -include_lib("public_key/include/public_key.hrl").
.fi
.LP
The following data types are used in the functions for \fIpublic_key\fR\&:
.RS 2
.TP 2
.B
\fIoid()\fR\&:
Object identifier, a tuple of integers as generated by the \fIASN\&.1\fR\& compiler\&.
.TP 2
.B
\fIboolean() =\fR\&:
\fItrue | false\fR\&
.TP 2
.B
\fIstring() =\fR\&:
\fI[bytes()]\fR\&
.TP 2
.B
\fIder_encoded() =\fR\&:
\fIbinary()\fR\&
.TP 2
.B
\fIpki_asn1_type() =\fR\&:
\fI\&'Certificate\&'\fR\&
.RS 2
.LP
\fI| \&'RSAPrivateKey\&'\fR\&
.RE

.RS 2
.LP
\fI| \&'RSAPublicKey\&'\fR\&
.RE

.RS 2
.LP
\fI| \&'DSAPrivateKey\&'\fR\&
.RE

.RS 2
.LP
\fI| \&'DSAPublicKey\&'\fR\&
.RE

.RS 2
.LP
\fI| \&'DHParameter\&'\fR\&
.RE

.RS 2
.LP
\fI| \&'SubjectPublicKeyInfo\&'\fR\&
.RE

.RS 2
.LP
\fI| \&'PrivateKeyInfo\&'\fR\&
.RE

.RS 2
.LP
\fI| \&'CertificationRequest\&'\fR\&
.RE

.RS 2
.LP
\fI| \&'CertificateList\&'\fR\&
.RE

.RS 2
.LP
\fI| \&'ECPrivateKey\&'\fR\&
.RE

.RS 2
.LP
\fI| \&'EcpkParameters\&'\fR\&
.RE

.TP 2
.B
\fIpem_entry () =\fR\&:
\fI{pki_asn1_type(), binary(), %% DER or encrypted DER\fR\&
.RS 2
.LP
\fI not_encrypted | cipher_info()}\fR\&
.RE

.TP 2
.B
\fIcipher_info() = \fR\&:
\fI{"RC2-CBC" | "DES-CBC" | "DES-EDE3-CBC", crypto:strong_rand_bytes(8)\fR\&
.RS 2
.LP
\fI| {#\&'PBEParameter{}, digest_type()} | #\&'PBES2-params\&'{}}\fR\&
.RE

.TP 2
.B
\fIpublic_key() =\fR\&:
\fIrsa_public_key() | dsa_public_key() | ec_public_key()\fR\&
.TP 2
.B
\fIprivate_key() =\fR\&:
\fIrsa_private_key() | dsa_private_key() | ec_private_key()\fR\&
.TP 2
.B
\fIrsa_public_key() =\fR\&:
\fI#\&'RSAPublicKey\&'{}\fR\&
.TP 2
.B
\fIrsa_private_key() =\fR\&:
\fI#\&'RSAPrivateKey\&'{}\fR\&
.TP 2
.B
\fIdsa_public_key() =\fR\&:
\fI{integer(), #\&'Dss-Parms\&'{}}\fR\&
.TP 2
.B
\fIdsa_private_key() =\fR\&:
\fI#\&'DSAPrivateKey\&'{}\fR\&
.TP 2
.B
\fIec_public_key()\fR\&:
= \fI{#\&'ECPoint\&'{}, #\&'ECParameters\&'{} | {namedCurve, oid()}}\fR\&
.TP 2
.B
\fIec_private_key() =\fR\&:
\fI#\&'ECPrivateKey\&'{}\fR\&
.TP 2
.B
\fIpublic_crypt_options() =\fR\&:
\fI[{rsa_pad, rsa_padding()}]\fR\&
.TP 2
.B
\fIrsa_padding() =\fR\&:
\fI\&'rsa_pkcs1_padding\&'\fR\&
.RS 2
.LP
\fI| \&'rsa_pkcs1_oaep_padding\&'\fR\&
.RE

.RS 2
.LP
\fI| \&'rsa_no_padding\&'\fR\&
.RE

.TP 2
.B
\fIdigest_type() = \fR\&:
Union of \fIrsa_digest_type()\fR\&, \fIdss_digest_type()\fR\&, and \fIecdsa_digest_type()\fR\&\&.
.TP 2
.B
\fIrsa_digest_type() = \fR\&:
\fI\&'md5\&' | \&'sha\&' | \&'sha224\&' | \&'sha256\&' | \&'sha384\&' | \&'sha512\&'\fR\&
.TP 2
.B
\fIdss_digest_type() = \fR\&:
\fI\&'sha\&'\fR\&
.TP 2
.B
\fIecdsa_digest_type() = \fR\&:
\fI\&'sha\&'| \&'sha224\&' | \&'sha256\&' | \&'sha384\&' | \&'sha512\&'\fR\&
.TP 2
.B
\fIcrl_reason() = \fR\&:
\fIunspecified\fR\&
.RS 2
.LP
\fI| keyCompromise\fR\&
.RE

.RS 2
.LP
\fI| cACompromise\fR\&
.RE

.RS 2
.LP
\fI| affiliationChanged\fR\&
.RE

.RS 2
.LP
\fI| superseded\fR\&
.RE

.RS 2
.LP
\fI| cessationOfOperation\fR\&
.RE

.RS 2
.LP
\fI| certificateHold\fR\&
.RE

.RS 2
.LP
\fI| privilegeWithdrawn\fR\&
.RE

.RS 2
.LP
\fI| aACompromise\fR\&
.RE

.TP 2
.B
\fIissuer_name() =\fR\&:
\fI{rdnSequence,[#\&'AttributeTypeAndValue\&'{}]}\fR\&
.TP 2
.B
\fIssh_file() =\fR\&:
\fIopenssh_public_key\fR\&
.RS 2
.LP
\fI| rfc4716_public_key\fR\&
.RE

.RS 2
.LP
\fI| known_hosts\fR\&
.RE

.RS 2
.LP
\fI| auth_keys\fR\&
.RE

.RE
.SH EXPORTS
.LP
.B
compute_key(OthersKey, MyKey)->
.br
.B
compute_key(OthersKey, MyKey, Params)->
.br
.RS
.LP
Types:

.RS 3
OthersKey = #\&'ECPoint\&'{} | binary(), MyKey = #\&'ECPrivateKey\&'{} | binary()
.br
Params = #\&'DHParameter\&'{}
.br
.RE
.RE
.RS
.LP
Computes shared secret\&.
.RE

.LP
.B
decrypt_private(CipherText, Key) -> binary()
.br
.B
decrypt_private(CipherText, Key, Options) -> binary()
.br
.RS
.LP
Types:

.RS 3
CipherText = binary()
.br
Key = rsa_private_key()
.br
Options = public_crypt_options()
.br
.RE
.RE
.RS
.LP
Public-key decryption using the private key\&. See also \fBcrypto:private_decrypt/4\fR\&
.RE

.LP
.B
decrypt_public(CipherText, Key) - > binary()
.br
.B
decrypt_public(CipherText, Key, Options) - > binary()
.br
.RS
.LP
Types:

.RS 3
CipherText = binary()
.br
Key = rsa_public_key()
.br
Options = public_crypt_options()
.br
.RE
.RE
.RS
.LP
Public-key decryption using the public key\&. See also \fBcrypto:public_decrypt/4\fR\&
.RE

.LP
.B
der_decode(Asn1type, Der) -> term()
.br
.RS
.LP
Types:

.RS 3
Asn1Type = atom()
.br
.RS 2
ASN\&.1 type present in the Public Key applications ASN\&.1 specifications\&.
.RE
Der = der_encoded()
.br
.RE
.RE
.RS
.LP
Decodes a public-key ASN\&.1 DER encoded entity\&.
.RE

.LP
.B
der_encode(Asn1Type, Entity) -> der_encoded()
.br
.RS
.LP
Types:

.RS 3
Asn1Type = atom()
.br
.RS 2
ASN\&.1 type present in the Public Key applications ASN\&.1 specifications\&.
.RE
Entity = term()
.br
.RS 2
Erlang representation of \fIAsn1Type\fR\&
.RE
.RE
.RE
.RS
.LP
Encodes a public-key entity with ASN\&.1 DER encoding\&.
.RE

.LP
.B
dh_gex_group(MinSize, SuggestedSize, MaxSize, Groups) -> {ok, {Size,Group}} | {error,Error}
.br
.RS
.LP
Types:

.RS 3
MinSize = positive_integer()
.br
SuggestedSize = positive_integer()
.br
MaxSize = positive_integer()
.br
Groups = undefined | [{Size,[{G,P}]}]
.br
Size = positive_integer()
.br
Group = {G,P}
.br
G = positive_integer()
.br
P = positive_integer()
.br
.RE
.RE
.RS
.LP
Selects a group for Diffie-Hellman key exchange with the key size in the range \fIMinSize\&.\&.\&.MaxSize\fR\& and as close to \fISuggestedSize\fR\& as possible\&. If \fIGroups == undefined\fR\& a default set will be used, otherwise the group is selected from \fIGroups\fR\&\&.
.LP
First a size, as close as possible to SuggestedSize, is selected\&. Then one group with that key size is randomly selected from the specified set of groups\&. If no size within the limits of \fIMinSize\fR\& and \fIMaxSize\fR\& is available, \fI{error,no_group_found}\fR\& is returned\&.
.LP
The default set of groups is listed in \fIlib/public_key/priv/moduli\fR\&\&. This file may be regenerated like this:
.LP
.nf

	$> cd $ERL_TOP/lib/public_key/priv/
	$> generate
         ---- wait until all background jobs has finished. It may take several days !
	$> cat moduli-* > moduli
	$> cd ..; make 
      
.fi
.RE

.LP
.B
encrypt_private(PlainText, Key) -> binary()
.br
.RS
.LP
Types:

.RS 3
PlainText = binary()
.br
Key = rsa_private_key()
.br
.RE
.RE
.RS
.LP
Public-key encryption using the private key\&. See also \fBcrypto:private_encrypt/4\fR\&\&.
.RE

.LP
.B
encrypt_public(PlainText, Key) -> binary()
.br
.RS
.LP
Types:

.RS 3
PlainText = binary()
.br
Key = rsa_public_key()
.br
.RE
.RE
.RS
.LP
Public-key encryption using the public key\&. See also \fBcrypto:public_encrypt/4\fR\&\&.
.RE

.LP
.B
generate_key(Params) -> {Public::binary(), Private::binary()} | #\&'ECPrivateKey\&'{} 
.br
.RS
.LP
Types:

.RS 3
Params = #\&'DHParameter\&'{} | {namedCurve, oid()} | #\&'ECParameters\&'{}
.br
.RE
.RE
.RS
.LP
Generates a new keypair\&.
.RE

.LP
.B
pem_decode(PemBin) -> [pem_entry()]
.br
.RS
.LP
Types:

.RS 3
PemBin = binary()
.br
.RS 2
Example {ok, PemBin} = file:read_file("cert\&.pem")\&.
.RE
.RE
.RE
.RS
.LP
Decodes PEM binary data and returns entries as ASN\&.1 DER encoded entities\&.
.RE

.LP
.B
pem_encode(PemEntries) -> binary()
.br
.RS
.LP
Types:

.RS 3
 PemEntries = [pem_entry()] 
.br
.RE
.RE
.RS
.LP
Creates a PEM binary\&.
.RE

.LP
.B
pem_entry_decode(PemEntry) -> term()
.br
.B
pem_entry_decode(PemEntry, Password) -> term()
.br
.RS
.LP
Types:

.RS 3
PemEntry = pem_entry()
.br
Password = string()
.br
.RE
.RE
.RS
.LP
Decodes a PEM entry\&. \fIpem_decode/1\fR\& returns a list of PEM entries\&. Notice that if the PEM entry is of type \&'SubjectPublickeyInfo\&', it is further decoded to an \fIrsa_public_key()\fR\& or \fIdsa_public_key()\fR\&\&.
.RE

.LP
.B
pem_entry_encode(Asn1Type, Entity) -> pem_entry()
.br
.B
pem_entry_encode(Asn1Type, Entity, {CipherInfo, Password}) -> pem_entry()
.br
.RS
.LP
Types:

.RS 3
Asn1Type = pki_asn1_type()
.br
Entity = term()
.br
.RS 2
Erlang representation of \fIAsn1Type\fR\&\&. If \fIAsn1Type\fR\& is \&'SubjectPublicKeyInfo\&', \fIEntity\fR\& must be either an \fIrsa_public_key()\fR\&, \fIdsa_public_key()\fR\& or an \fIec_public_key()\fR\& and this function creates the appropriate \&'SubjectPublicKeyInfo\&' entry\&. 
.RE
CipherInfo = cipher_info()
.br
Password = string()
.br
.RE
.RE
.RS
.LP
Creates a PEM entry that can be feed to \fIpem_encode/1\fR\&\&.
.RE

.LP
.B
pkix_decode_cert(Cert, otp|plain) -> #\&'Certificate\&'{} | #\&'OTPCertificate\&'{}
.br
.RS
.LP
Types:

.RS 3
Cert = der_encoded()
.br
.RE
.RE
.RS
.LP
Decodes an ASN\&.1 DER-encoded PKIX certificate\&. Option \fIotp\fR\& uses the customized ASN\&.1 specification OTP-PKIX\&.asn1 for decoding and also recursively decode most of the standard parts\&.
.RE

.LP
.B
pkix_encode(Asn1Type, Entity, otp | plain) -> der_encoded()
.br
.RS
.LP
Types:

.RS 3
Asn1Type = atom()
.br
.RS 2
The ASN\&.1 type can be \&'Certificate\&', \&'OTPCertificate\&' or a subtype of either\&.
.RE
Entity = #\&'Certificate\&'{} | #\&'OTPCertificate\&'{} | a valid subtype
.br
.RE
.RE
.RS
.LP
DER encodes a PKIX x509 certificate or part of such a certificate\&. This function must be used for encoding certificates or parts of certificates that are decoded/created in the \fIotp\fR\& format, whereas for the plain format this function directly calls \fIder_encode/2\fR\&\&.
.RE

.LP
.B
pkix_is_issuer(Cert, IssuerCert) -> boolean()
.br
.RS
.LP
Types:

.RS 3
Cert = der_encoded() | #\&'OTPCertificate\&'{} | #\&'CertificateList\&'{}
.br
IssuerCert = der_encoded() | #\&'OTPCertificate\&'{}
.br
.RE
.RE
.RS
.LP
Checks if \fIIssuerCert\fR\& issued \fICert\fR\&\&.
.RE

.LP
.B
pkix_is_fixed_dh_cert(Cert) -> boolean()
.br
.RS
.LP
Types:

.RS 3
Cert = der_encoded() | #\&'OTPCertificate\&'{}
.br
.RE
.RE
.RS
.LP
Checks if a certificate is a fixed Diffie-Hellman certificate\&.
.RE

.LP
.B
pkix_is_self_signed(Cert) -> boolean()
.br
.RS
.LP
Types:

.RS 3
Cert = der_encoded() | #\&'OTPCertificate\&'{}
.br
.RE
.RE
.RS
.LP
Checks if a certificate is self-signed\&.
.RE

.LP
.B
pkix_issuer_id(Cert, IssuedBy) -> {ok, IssuerID} | {error, Reason}
.br
.RS
.LP
Types:

.RS 3
Cert = der_encoded() | #\&'OTPCertificate\&'{}
.br
IssuedBy = self | other
.br
IssuerID = {integer(), issuer_name()}
.br
.RS 2
The issuer id consists of the serial number and the issuers name\&.
.RE
Reason = term()
.br
.RE
.RE
.RS
.LP
Returns the issuer id\&.
.RE

.LP
.B
pkix_normalize_name(Issuer) -> Normalized
.br
.RS
.LP
Types:

.RS 3
Issuer = issuer_name()
.br
Normalized = issuer_name()
.br
.RE
.RE
.RS
.LP
Normalizes an issuer name so that it can be easily compared to another issuer name\&.
.RE

.LP
.B
pkix_path_validation(TrustedCert, CertChain, Options) -> {ok, {PublicKeyInfo, PolicyTree}} | {error, {bad_cert, Reason}} 
.br
.RS
.LP
Types:

.RS 3
TrustedCert = #\&'OTPCertificate\&'{} | der_encoded() | atom()
.br
.RS 2
Normally a trusted certificate, but it can also be a path-validation error that can be discovered while constructing the input to this function and that is to be run through the \fIverify_fun\fR\&\&. Examples are \fIunknown_ca\fR\& and \fIselfsigned_peer\&.\fR\&
.RE
CertChain = [der_encoded()]
.br
.RS 2
A list of DER-encoded certificates in trust order ending with the peer certificate\&.
.RE
Options = proplists:proplist()
.br
PublicKeyInfo = {?\&'rsaEncryption\&' | ?\&'id-dsa\&', rsa_public_key() | integer(), \&'NULL\&' | \&'Dss-Parms\&'{}}
.br
PolicyTree = term()
.br
.RS 2
At the moment this is always an empty list as policies are not currently supported\&.
.RE
Reason = cert_expired | invalid_issuer | invalid_signature | name_not_permitted | missing_basic_constraint | invalid_key_usage | {revoked, crl_reason()} | atom() 
.br
.RE
.RE
.RS
.LP
Performs a basic path validation according to RFC 5280\&. However, CRL validation is done separately by \fBpkix_crls_validate/3 \fR\& and is to be called from the supplied \fIverify_fun\fR\&\&.
.LP
Available options:
.RS 2
.TP 2
.B
{verify_fun, fun()}:
The fun must be defined as:
.LP
.nf

fun(OtpCert :: #'OTPCertificate'{},
    Event :: {bad_cert, Reason :: atom() | {revoked, atom()}} |
             {extension, #'Extension'{}},
    InitialUserState :: term()) ->
	{valid, UserState :: term()} |
	{valid_peer, UserState :: term()} |
	{fail, Reason :: term()} |
	{unknown, UserState :: term()}.
	  
.fi
.RS 2
.LP
If the verify callback fun returns \fI{fail, Reason}\fR\&, the verification process is immediately stopped\&. If the verify callback fun returns \fI{valid, UserState}\fR\&, the verification process is continued\&. This can be used to accept specific path validation errors, such as \fIselfsigned_peer\fR\&, as well as verifying application-specific extensions\&. If called with an extension unknown to the user application, the return value \fI{unknown, UserState}\fR\& is to be used\&.
.RE

.TP 2
.B
{max_path_length, integer()}:
 The \fImax_path_length\fR\& is the maximum number of non-self-issued intermediate certificates that can follow the peer certificate in a valid certification path\&. So, if \fImax_path_length\fR\& is 0, the PEER must be signed by the trusted ROOT-CA directly, if it is 1, the path can be PEER, CA, ROOT-CA, if it is 2, the path can be PEER, CA, CA, ROOT-CA, and so on\&. 
.RE
.LP
Possible reasons for a bad certificate:
.RS 2
.TP 2
.B
cert_expired:
Certificate is no longer valid as its expiration date has passed\&.
.TP 2
.B
invalid_issuer:
Certificate issuer name does not match the name of the issuer certificate in the chain\&.
.TP 2
.B
invalid_signature:
Certificate was not signed by its issuer certificate in the chain\&.
.TP 2
.B
name_not_permitted:
Invalid Subject Alternative Name extension\&.
.TP 2
.B
missing_basic_constraint:
Certificate, required to have the basic constraints extension, does not have a basic constraints extension\&.
.TP 2
.B
invalid_key_usage:
Certificate key is used in an invalid way according to the key-usage extension\&.
.TP 2
.B
{revoked, crl_reason()}:
Certificate has been revoked\&.
.TP 2
.B
atom():
Application-specific error reason that is to be checked by the \fIverify_fun\fR\&\&.
.RE
.RE

.LP
.B
pkix_crl_issuer(CRL) -> issuer_name()
.br
.RS
.LP
Types:

.RS 3
CRL = der_encoded() | #\&'CertificateList\&'{} 
.br
.RE
.RE
.RS
.LP
Returns the issuer of the \fICRL\fR\&\&.
.RE

.LP
.B
pkix_crls_validate(OTPCertificate, DPAndCRLs, Options) -> CRLStatus()
.br
.RS
.LP
Types:

.RS 3
OTPCertificate = #\&'OTPCertificate\&'{}
.br
DPAndCRLs = [{DP::#\&'DistributionPoint\&'{}, {DerCRL::der_encoded(), CRL::#\&'CertificateList\&'{}}}] 
.br
Options = proplists:proplist()
.br
CRLStatus() = valid | {bad_cert, revocation_status_undetermined} | {bad_cert, {revoked, crl_reason()}}
.br
.RE
.RE
.RS
.LP
Performs CRL validation\&. It is intended to be called from the verify fun of \fB pkix_path_validation/3 \fR\&\&.
.LP
Available options:
.RS 2
.TP 2
.B
{update_crl, fun()}:
The fun has the following type specification:
.LP
.nf
 fun(#'DistributionPoint'{}, #'CertificateList'{}) ->
        #'CertificateList'{}
.fi
.RS 2
.LP
The fun uses the information in the distribution point to access the latest possible version of the CRL\&. If this fun is not specified, Public Key uses the default implementation:
.RE

.LP
.nf
 fun(_DP, CRL) -> CRL end
.fi
.TP 2
.B
{issuer_fun, fun()}:
The fun has the following type specification:
.LP
.nf

fun(#'DistributionPoint'{}, #'CertificateList'{},
    {rdnSequence,[#'AttributeTypeAndValue'{}]}, term()) ->
	{ok, #'OTPCertificate'{}, [der_encoded]}
.fi
.RS 2
.LP
The fun returns the root certificate and certificate chain that has signed the CRL\&.
.RE

.LP
.nf
 fun(DP, CRL, Issuer, UserState) -> {ok, RootCert, CertChain}
.fi
.RE
.RE

.LP
.B
pkix_crl_verify(CRL, Cert) -> boolean()
.br
.RS
.LP
Types:

.RS 3
CRL = der_encoded() | #\&'CertificateList\&'{} 
.br
Cert = der_encoded() | #\&'OTPCertificate\&'{} 
.br
.RE
.RE
.RS
.LP
Verify that \fICert\fR\& is the \fICRL\fR\& signer\&.
.RE

.LP
.B
pkix_dist_point(Cert) -> DistPoint
.br
.RS
.LP
Types:

.RS 3
 Cert = der_encoded() | #\&'OTPCertificate\&'{} 
.br
 DistPoint = #\&'DistributionPoint\&'{}
.br
.RE
.RE
.RS
.LP
Creates a distribution point for CRLs issued by the same issuer as \fICert\fR\&\&. Can be used as input to \fBpkix_crls_validate/3 \fR\& 
.RE

.LP
.B
pkix_dist_points(Cert) -> DistPoints
.br
.RS
.LP
Types:

.RS 3
 Cert = der_encoded() | #\&'OTPCertificate\&'{} 
.br
 DistPoints = [#\&'DistributionPoint\&'{}]
.br
.RE
.RE
.RS
.LP
Extracts distribution points from the certificates extensions\&.
.RE

.LP
.B
pkix_match_dist_point(CRL, DistPoint) -> boolean()
.br
.RS
.LP
Types:

.RS 3
CRL = der_encoded() | #\&'CertificateList\&'{} 
.br
DistPoint = #\&'DistributionPoint\&'{}
.br
.RE
.RE
.RS
.LP
Checks whether the given distribution point matches the Issuing Distribution Point of the CRL, as described in RFC 5280\&. If the CRL doesn\&'t have an Issuing Distribution Point extension, the distribution point always matches\&.
.RE

.LP
.B
pkix_sign(#\&'OTPTBSCertificate\&'{}, Key) -> der_encoded()
.br
.RS
.LP
Types:

.RS 3
Key = rsa_private_key() | dsa_private_key()
.br
.RE
.RE
.RS
.LP
Signs an \&'OTPTBSCertificate\&'\&. Returns the corresponding DER-encoded certificate\&.
.RE

.LP
.B
pkix_sign_types(AlgorithmId) -> {DigestType, SignatureType}
.br
.RS
.LP
Types:

.RS 3
AlgorithmId = oid()
.br
.RS 2
Signature OID from a certificate or a certificate revocation list\&.
.RE
DigestType = rsa_digest_type() | dss_digest_type()
.br
SignatureType = rsa | dsa | ecdsa
.br
.RE
.RE
.RS
.LP
Translates signature algorithm OID to Erlang digest and signature types\&.
.RE

.LP
.B
pkix_verify(Cert, Key) -> boolean()
.br
.RS
.LP
Types:

.RS 3
Cert = der_encoded()
.br
Key = rsa_public_key() | dsa_public_key() | ec_public_key()
.br
.RE
.RE
.RS
.LP
Verifies PKIX x\&.509 certificate signature\&.
.RE

.LP
.B
sign(Msg, DigestType, Key) -> binary()
.br
.RS
.LP
Types:

.RS 3
Msg = binary() | {digest,binary()}
.br
.RS 2
The \fIMsg\fR\& is either the binary "plain text" data to be signed or it is the hashed value of "plain text", that is, the digest\&.
.RE
DigestType = rsa_digest_type() | dss_digest_type() | ecdsa_digest_type()
.br
Key = rsa_private_key() | dsa_private_key() | ec_private_key()
.br
.RE
.RE
.RS
.LP
Creates a digital signature\&.
.RE

.LP
.B
ssh_decode(SshBin, Type) -> [{public_key(), Attributes::list()}]
.br
.RS
.LP
Types:

.RS 3
SshBin = binary()
.br
.RS 2
Example \fI{ok, SshBin} = file:read_file("known_hosts")\fR\&\&.
.RE
Type = public_key | ssh_file()
.br
.RS 2
If \fIType\fR\& is \fIpublic_key\fR\& the binary can be either an RFC4716 public key or an OpenSSH public key\&.
.RE
.RE
.RE
.RS
.LP
Decodes an SSH file-binary\&. In the case of \fIknown_hosts\fR\& or \fIauth_keys\fR\&, the binary can include one or more lines of the file\&. Returns a list of public keys and their attributes, possible attribute values depends on the file type represented by the binary\&.
.RS 2
.TP 2
.B
RFC4716 attributes - see RFC 4716\&.:
{headers, [{string(), utf8_string()}]}
.TP 2
.B
auth_key attributes - see manual page for sshd\&.:
{comment, string()}{options, [string()]}{bits, integer()} - In SSH version 1 files\&.
.TP 2
.B
known_host attributes - see manual page for sshd\&.:
{hostnames, [string()]}{comment, string()}{bits, integer()} - In SSH version 1 files\&.
.RE
.RE

.LP
.B
ssh_encode([{Key, Attributes}], Type) -> binary()
.br
.RS
.LP
Types:

.RS 3
Key = public_key()
.br
Attributes = list()
.br
Type = ssh_file()
.br
.RE
.RE
.RS
.LP
Encodes a list of SSH file entries (public keys and attributes) to a binary\&. Possible attributes depend on the file type, see \fB ssh_decode/2 \fR\&\&.
.RE

.LP
.B
ssh_hostkey_fingerprint(HostKey) -> string()
.br
.B
ssh_hostkey_fingerprint(DigestType, HostKey) -> string()
.br
.RS
.LP
Types:

.RS 3
Key = public_key()
.br
DigestType = digest_type()
.br
.RE
.RE
.RS
.LP
Calculates a ssh fingerprint from a public host key as openssh does\&.
.LP
The algorithm in \fIssh_hostkey_fingerprint/1\fR\& is md5 to be compatible with older ssh-keygen commands\&. The string from the second variant is prepended by the algorithm name in uppercase as in newer ssh-keygen commands\&.
.LP
Examples:
.LP
.nf

 2> public_key:ssh_hostkey_fingerprint(Key).    
 "f5:64:a6:c1:5a:cb:9f:0a:10:46:a2:5c:3e:2f:57:84"

 3> public_key:ssh_hostkey_fingerprint(md5,Key).
 "MD5:f5:64:a6:c1:5a:cb:9f:0a:10:46:a2:5c:3e:2f:57:84"

 4> public_key:ssh_hostkey_fingerprint(sha,Key).
 "SHA1:bSLY/C4QXLDL/Iwmhyg0PGW9UbY"

 5> public_key:ssh_hostkey_fingerprint(sha256,Key).
 "SHA256:aZGXhabfbf4oxglxltItWeHU7ub3Dc31NcNw2cMJePQ"
    
.fi
.RE

.LP
.B
verify(Msg, DigestType, Signature, Key) -> boolean()
.br
.RS
.LP
Types:

.RS 3
Msg = binary() | {digest,binary()}
.br
.RS 2
The \fIMsg\fR\& is either the binary "plain text" data or it is the hashed value of "plain text", that is, the digest\&.
.RE
DigestType = rsa_digest_type() | dss_digest_type() | ecdsa_digest_type()
.br
Signature = binary()
.br
Key = rsa_public_key() | dsa_public_key() | ec_public_key()
.br
.RE
.RE
.RS
.LP
Verifies a digital signature\&.
.RE

.LP
.B
short_name_hash(Name) -> string()
.br
.RS
.LP
Types:

.RS 3
Name = issuer_name()
.br
.RE
.RE
.RS
.LP
Generates a short hash of an issuer name\&. The hash is returned as a string containing eight hexadecimal digits\&.
.LP
The return value of this function is the same as the result of the commands \fIopenssl crl -hash\fR\& and \fIopenssl x509 -issuer_hash\fR\&, when passed the issuer name of a CRL or a certificate, respectively\&. This hash is used by the \fIc_rehash\fR\& tool to maintain a directory of symlinks to CRL files, in order to facilitate looking up a CRL by its issuer name\&.
.RE