137 lines
2.9 KiB
Plaintext
137 lines
2.9 KiB
Plaintext
.TH EC 2
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.SH NAME
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ecassign,
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ecadd,
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ecmul,
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strtoec,
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ecgen,
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ecverify,
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ecpubverify,
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ecdsasign,
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ecdsaverify \- elliptic curve cryptography
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.SH SYNOPSIS
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.B #include <u.h>
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.br
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.B #include <libc.h>
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.br
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.B #include <mp.h>
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.br
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.B #include <libsec.h>
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.PP
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.B
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void ecdominit(ECdomain *dom, void (*init)(mpint *p, mpint *a, mpint *b, mpint *x, mpint *y, mpint *n, mpint *h));
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.PP
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.B
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void ecdomfree(ECdomain *dom);
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.PP
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.B
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void ecassign(ECdomain *dom, ECpoint *old, ECpoint *new);
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.PP
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.B
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void ecadd(ECdomain *dom, ECpoint *a, ECpoint *b, ECpoint *s);
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.PP
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.B
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void ecmul(ECdomain *dom, ECpoint *a, mpint *k, ECpoint *s);
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.PP
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.B
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ECpoint* strtoec(ECdomain *dom, char *s, char **rptr, ECpoint *p);
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.PP
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.B
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ECpriv* ecgen(ECdomain *dom, ECpriv *p);
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.PP
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.B
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int ecverify(ECdomain *dom, ECpoint *p);
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.PP
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.B
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int ecpubverify(ECdomain *dom, ECpub *p);
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.PP
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.B
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void ecdsasign(ECdomain *dom, ECpriv *priv, uchar *dig, int dlen, mpint *r, mpint *s);
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.PP
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.B
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int ecdsaverify(ECdomain *dom, ECpub *pub, uchar *dig, int dlen, mpint *r, mpint *s);
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.DT
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.SH DESCRIPTION
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These functions implement elliptic curve cryptography.
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An elliptic curve together with cryptographic parameters are specified using an
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.B ECdomain
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struct.
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Points on the curve are represented by
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.B ECpoint
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structs.
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.PP
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.B ecdominit
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initializes a
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.B ECdomain
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struct and calls the
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.B init
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function such as
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.B secp256r1
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which fills in the parameters of the curve.
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.PP
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.B ecdomfree
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frees the parameters of the curve and zeros the struct. It does
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not free the memory of the struct itself.
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.PP
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.BR ecassign ", " ecadd " and " ecmul
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are analogous to their counterparts in
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.IR mp (2).
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.PP
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.B strtoec
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converts a hex string representing an octet string as specified in
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.I Standards for Efficient Cryptography (SEC) 1
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to an
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.B ECpoint
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struct. Both uncompressed and compressed formats are supported.
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If
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.B rptr
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is not
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.BR nil ,
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it is used to return the position in the string where the parser stopped.
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If
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.BR p " is " nil
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space is allocated automatically, else the given struct is used.
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.PP
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.B ecverify
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and
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.B ecpubverify
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verify that the given point or public key, respectively, is valid.
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.PP
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.B ecgen
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generates a keypair and returns a pointer to it.
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If
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.BR p " is " nil
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space is allocated automatically, else the given struct is used.
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.PP
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.B ecdsasign
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and
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.B ecdsaverify
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create or verify, respectively, a signature using the ECDSA scheme specified in
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.I SEC 1.
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It is absolutely vital that
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.B dig
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is a cryptographic hash to the message.
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.B ecdsasign
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writes the signature to
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.BR r " and " s
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which are assumed to be allocated properly.
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.SH RETURN VALUE
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.B *verify
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functions return
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.B 1
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for a positive result.
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Functions returning pointers may return
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.B nil
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in case of error
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.I (e.g.
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failing
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.IR malloc (2)).
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.SH SOURCE
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.B /sys/src/libsec/port/ecc.c
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.SH SEE ALSO
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.I
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Standards for Efficient Cryptography (SEC) 1: Elliptic Curve Cryptography
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- Certicom Research, 2009
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.SH HISTORY
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This implementation of elliptic curve cryptography first appeared in 9front (June, 2012).
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