NAME

oldauth: certtostr, pktostr, sktostr, strtocert, strtopk, strtosk, sign, verify, readauthinfo, writeauthinfo - encoding for original Inferno authentication protocol

SYNOPSIS

include "ipints.m";
include "crypt.m";
include "oldauth.m";
oldauth := load Oldauth Oldauth->PATH;

Certificate: adt
{
    sa:     string;
    ha:     string;
    signer: string;
    exp:    int;
    sig:    ref Crypt->PKsig;
};

Authinfo: adt
{
    mysk:   ref Crypt->SK;
    mypk:   ref Crypt->PK;
    owner:  string;
    cert:   ref Certificate;
    spk:    ref Crypt->PK;
    alpha:  ref IPints->IPint;
    p:      ref IPints->IPint;
};

sign:   fn (sk: ref Crypt->SK, signer: string, exp: int,
          state: ref Crypt->DigestState, ha: string): ref Certificate;
verify: fn (pk: ref Crypt->PK, cert: ref Certificate,
          state: ref Crypt->DigestState): int;

strtocert: fn(s: string): ref Certificate;
certtostr: fn(c: ref Certificate): string;
strtopk:   fn(s: string): (ref Crypt->PK, string);
pktostr:   fn(pk: ref Crypt->PK, owner: string): string;
strtosk:   fn(s: string): (ref Crypt->SK, string);
sktostr:   fn(sk: ref Crypt->SK, owner: string): string;

readauthinfo:   fn(filename: string): ref Authinfo;
writeauthinfo:  fn(filename: string, info: ref Authinfo): int;

DESCRIPTION

Certificates, public keys, and private keys are passed over networks and between applications using a Unicode representation. This collection of functions provide a means to convert adts supplied by the system to and from their portable textual representation. These routines are used by login(2) and factotum(4) to implement the Inferno authentication protocol.

Public and private keys are represented by Crypt->PK and Crypt->SK (see keyring-intro(2)). An authentication domain is represented by the public key of the domain's signer, typically in control of a keyfs(4) and running a logind(8). Two adts associate a public/private key pair with a user name within a specific authentication domain:

Authinfo

The Authinfo adt contains an individual user's private and public key, a human-readable name for the key (eg, a user name), the signer's certificate and the signer's public key, and the Diffie-Hellman parameters. The signer's certificate binds the user's public key to the given key name in the signer's domain.

Certificate

The Certificate adt contains a digital signature with the certification of the trusted authority (CA). The signature covers not only the user's public key, but the key's name, the signer's name and the expiration time of the certificate. Both the key's name and the signer's name are local to the signer's domain.

Init must be called before using any other operation in the module.

Sign returns a Certificate containing the digital signature using secret key sk of a digest's state, which is the output of the hash algorithm named ha, combined with the hash of the signer's name, and the certificate's expiration time (in seconds from the Epoch). Valid hash algorithms are sha1 and md5. The expiry time should be zero if the certificate does not expire. Typically the state is the result of hashing

array of byte pktostr(pk, username)

for a given public key pk that is associated with the given username by the signer.

Verify checks that the given Certificate is the result of signing the given state using the secret (private) key corresponding to public key pk. It returns true (non-zero) if the certificate is valid, including the signer's name, and the expiration time; the caller must enforce the expiration time if desired. It returns false (zero) if the certificate is invalid.

Sign creates a digital signature of a digest from the concatenation of: a message, the name of the signer, and an expiration time. State is the digest state after running sha1, md4 or md5 over the message. Ha is a string specifying the hash algorithm to use: "sha", "sha1", "md4" or "md5". Sign extends the digest to cover the signer's name (taken from the private key, sk) and the expiration time. It returns a certificate containing the digital signature of the digest, signer name, hash algorithm and signature algorithm. If any parameter is invalid, sign returns nil. The signature algorithm is implied by the type of the private key.

Verify uses public key pk to verify a certificate. It returns non-zero (true) if the certificate is valid; zero (false) otherwise. State is the digest state after running the chosen digest algorithm over the message.

The remaining operations fetch and store those values and convert to and from text representations for use in protocols and for storage.

Strtocert takes a string argument containing a varying number of newline-separated fields: a signature algorithm, a hash algorithm, a signer's name, an expiration time, and values representing a digital signature. It returns the corresponding Certificate. If the string is of improper format, the result is nil.

Certtostr performs the inverse operation: takes the Certificate c and produces a text string suitable for communication over a network. Note that the string will contain newline characters.

Strtopk and strtosk take as their arguments a string s representing the public and private keys respectively. S contains an algorithm name, a user name and values representing the key. Each returns a tuple (k, s), where k is the resulting key value (ie, Crypt->PK or Crypt->SK) and s is a string giving the name associated with the key, typically a user name. If the format of s is invalid, k is nil, and s contains a diagnostic.

Pktostr and sktostr perform the inverse operations: they take a public key (secret key) pk or sk, the owner name to be associated with that key, and produce a printable representation as a string. The owner names the user that owns the key; in the case of a public key, the user is expected to possess the corresponding private key.

Readauthinfo reads a representation of an Authinfo from a file. It returns nil if there is a read error or a conversion error; it returns a reference to the Authinfo otherwise.

Writeauthinfo writes a representation of info to a file. It returns -1 if the write operation fails, 0 otherwise.

SOURCE

/appl/lib/oldauth.b

SEE ALSO

crypt-intro(2), ipints(2), security-intro(2)

SECURITY-OLDAUTH(2 )

Rev:  Tue Mar 31 02:42:39 GMT 2015