Module: SelfCrypto::Util

Defined in:
lib/self_crypto/utility.rb,
ext/self_crypto/utility.c

Class Method Summary collapse

Class Method Details

.ed25519_pk_to_curve25519(ed25519_pk) ⇒ Object



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# File 'ext/self_crypto/utility.c', line 27

static VALUE ed25519_pk_to_curve25519(VALUE self, VALUE ed25519_pk)
{
    VALUE curve25519_sk;
    void  *pk_ptr, *dec_ptr, *enc_ptr;
    size_t pk_sz, dec_sz, enc_sz, success;

    if(rb_obj_is_kind_of(ed25519_pk, rb_eval_string("String")) != Qtrue){
        rb_raise(rb_eTypeError, "ed25519_pk must be kind of String");
    }

    pk_sz = crypto_sign_publickeybytes();

    if((dec_ptr = malloc(pk_sz)) == NULL){
        rb_raise(rb_eNoMemError, "%s()", __FUNCTION__);
    }

    success = sodium_base642bin(
        dec_ptr,
        pk_sz,
        RSTRING_PTR(ed25519_pk),
        RSTRING_LEN(ed25519_pk),
        NULL,
        &dec_sz,
        NULL,
        sodium_base64_VARIANT_ORIGINAL_NO_PADDING
    );

    if(success != 0) {
        free(dec_ptr);
        rb_raise(rb_eTypeError, "could not convert ed25519 public key");
    }

    if((pk_ptr = malloc(pk_sz)) == NULL){
        rb_raise(rb_eNoMemError, "%s()", __FUNCTION__);
    }

    success = crypto_sign_ed25519_pk_to_curve25519(
        pk_ptr,
        dec_ptr
    );

    free(dec_ptr);

    if(success != 0) {
        free(pk_ptr);
        rb_raise(rb_eTypeError, "could not convert ed25519 public key");
    }

    enc_sz = sodium_base64_ENCODED_LEN(pk_sz, sodium_base64_VARIANT_ORIGINAL_NO_PADDING);

    if((enc_ptr = malloc(enc_sz)) == NULL){
        rb_raise(rb_eNoMemError, "%s()", __FUNCTION__);
    }

    sodium_bin2base64(
        enc_ptr,
        enc_sz,
        pk_ptr,
        pk_sz,
        sodium_base64_VARIANT_ORIGINAL_NO_PADDING
    );

    free(pk_ptr);

    curve25519_sk = rb_str_new(enc_ptr, 44);

    free(enc_ptr);

    return curve25519_sk;
}