@CanIgnoreReturnValue
    public Builder setPrimes(SecretBigInteger p, SecretBigInteger q) {
      this.p = p;
      this.q = q;
      return this;
    }
Sets the prime factors p and q.

<p>This is required.
java_src/src/main/java/com/google/crypto/tink/signature/RsaSsaPkcs1PrivateKey.java